CA2287797A1 - Anchoring overhangs to walls to strengthen roofs against hurricanes - Google Patents
Anchoring overhangs to walls to strengthen roofs against hurricanes Download PDFInfo
- Publication number
- CA2287797A1 CA2287797A1 CA002287797A CA2287797A CA2287797A1 CA 2287797 A1 CA2287797 A1 CA 2287797A1 CA 002287797 A CA002287797 A CA 002287797A CA 2287797 A CA2287797 A CA 2287797A CA 2287797 A1 CA2287797 A1 CA 2287797A1
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- Prior art keywords
- roof
- wall
- clasp
- anchor
- frames
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Classifications
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B7/00—Roofs; Roof construction with regard to insulation
- E04B7/02—Roofs; Roof construction with regard to insulation with plane sloping surfaces, e.g. saddle roofs
- E04B7/04—Roofs; Roof construction with regard to insulation with plane sloping surfaces, e.g. saddle roofs supported by horizontal beams or the equivalent resting on the walls
- E04B7/045—Roofs; Roof construction with regard to insulation with plane sloping surfaces, e.g. saddle roofs supported by horizontal beams or the equivalent resting on the walls with connectors made of sheet metal for connecting the roof structure to the supporting wall
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H9/00—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate
- E04H9/14—Buildings, groups of buildings or shelters adapted to withstand or provide protection against abnormal external influences, e.g. war-like action, earthquake or extreme climate against other dangerous influences, e.g. tornadoes, floods
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
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- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Working Measures On Existing Buildindgs (AREA)
Abstract
This invention comprises ways and means of strengthening roofs to withstand hurricane winds using widely spaced anchor assemblies consisting of clasps and tension members to hold down the overhanging eave portion of the roof to strong anchors in existing structural members in the wall below. The wide spacing exploits the roof's bending strength and folded plate action along its length (in the direction across the framing members in the roof plane); the invention includes means of reinforcing that strength by means of beams where suitably strong anchorage points occur too far apart.
Alternatively, the invention includes means of strengthening a framed wall to receive and secure anchors where no framing exists at the desired point. The invention minimizes disruption of building and occupants, entailing little make-good, and the number of anchor assemblies, all serving to minimize costs. Where the underside of the eave is not closed in, ie. there's no soffit closure, then "U" clasps grip certain of the protruding rafters or truss extensions and are tied to the wall anchors. An alternative yoke type of clasp is described. Where the roof overhang is itself too weak against wind uplift the clasp points can be located suitably outboard of the exterior wall, toward the fascia, thereby reducing the cantilever span of the overhang while also tying down the roof proper. Where, on the other hand, soffit closures prevent access to the rafters, flanged clasps are fixed to the fascia and edge portions of the roof and tied to the wall anchors.
That also strengthens the overhangs, effectively removing their cantilever condition. The wall anchors are inserted into window or door bucks or frames or wall junctions to exploit the embedded load-spreader capability presented by such frames and junctions.
Preferred materials for the anchorage assemblies are non-corrosive steels, which may be blackened or otherwise coloured for appearance.
Alternatively, the invention includes means of strengthening a framed wall to receive and secure anchors where no framing exists at the desired point. The invention minimizes disruption of building and occupants, entailing little make-good, and the number of anchor assemblies, all serving to minimize costs. Where the underside of the eave is not closed in, ie. there's no soffit closure, then "U" clasps grip certain of the protruding rafters or truss extensions and are tied to the wall anchors. An alternative yoke type of clasp is described. Where the roof overhang is itself too weak against wind uplift the clasp points can be located suitably outboard of the exterior wall, toward the fascia, thereby reducing the cantilever span of the overhang while also tying down the roof proper. Where, on the other hand, soffit closures prevent access to the rafters, flanged clasps are fixed to the fascia and edge portions of the roof and tied to the wall anchors.
That also strengthens the overhangs, effectively removing their cantilever condition. The wall anchors are inserted into window or door bucks or frames or wall junctions to exploit the embedded load-spreader capability presented by such frames and junctions.
Preferred materials for the anchorage assemblies are non-corrosive steels, which may be blackened or otherwise coloured for appearance.
Description
BACKGROUND OF THE INVENTION
The apparently increasing frequency of Category 4 and 5 hurricanes portends more widespread destruction of houses and other buildings - and much of the destruction is needless. True, there may be little that can be done to safeguard existing communities against storm surge, downpours and mudslides, but the loss of roofs - often with "collateral damage" to life and limb and surrounding property - can be preventable.
Many, perhaps most, houses and other small buildings in the Caribbean and Central American "hurricane belt" can lose their roofs to Category 4 storms; much of such stock at risk in the USA might be little better built. Florida, followed by some Caribbean Islands and Bermuda, now requires resistance to Category 5 storms for new construction.
The intent here is to devise low cost retrofits of existing roofs to that level.
Recently designing a new house for Cayman Brac, I began to ponder the need to reinforce the existing stock, and to conceive affordable methods and gear. My structural engineering tasks included some monitoring of the builder's care with rugged but simple ties and diaphragms to meet Category 5 loads. That afforded opportunity to inspect Cayman buildings and talk to engineering colleagues there on the widespread inadequacies of the existing stock, even in these richest of the Caribbean islands. The design was finished and approved, and then came Category 5 Mitch in the fall of 1998.
It veered away from the Caymans at the last moment, missing them by 200 miles and stalling disastrously over the Bay Islands off Honduras. Studying photos of wind damage there, discussing weak points with the engineers pressed into better preparing the Caymans, and drawing upon decades of engineering work with many forms of house structures, I turned fully to the question of how to strengthen existing stock.
In the prior art as still practiced, hurricane-resisting retrofits remain uncommon, and favour only expensive houses. Designers approach each case as a one-off challenge. Until 1996 and later, patent files disclose very little focus on retrofit needs.
(The few so focused are mainly variations of steel cables, straps or nets deployed over the roof and anchored to the ground or foundation until the storm is over. One, US 5257483, 11/1993, Netek, expired, laboriously ties the lower end of each rafter to the wall by a strap screw-installed for the storm period.) In the absence of a practicable retrofit school of thought, or methods or gear, designers naturally think in terms of the galvanized steel straps that are well developed for new construction. First, however, soffits or ceilings have to be removed and, often, the exterior stucco or other cladding is stripped away to allow access to the roof rafters/trusses and the wall, respectively. The latter is often cut into to allow tying into the framing, or the reinforcing bars, ignoring the presence of "rough opening"
framings which intrinsically comprise embedded load-spreaders. All of this surgery is then covered over; the idea seems to be to hide all retrofits rather than leave them as "badges" of quality. Conventional hold-down straps are applied to each rafter, whereas wider spacing can work because of certain lengthwise spanning properties in most roofs.
Costs are high, with little market among "people's housing" despite the great need, and apparently little incentive to the busy engineers to develop that market and fill that need.
The apparently increasing frequency of Category 4 and 5 hurricanes portends more widespread destruction of houses and other buildings - and much of the destruction is needless. True, there may be little that can be done to safeguard existing communities against storm surge, downpours and mudslides, but the loss of roofs - often with "collateral damage" to life and limb and surrounding property - can be preventable.
Many, perhaps most, houses and other small buildings in the Caribbean and Central American "hurricane belt" can lose their roofs to Category 4 storms; much of such stock at risk in the USA might be little better built. Florida, followed by some Caribbean Islands and Bermuda, now requires resistance to Category 5 storms for new construction.
The intent here is to devise low cost retrofits of existing roofs to that level.
Recently designing a new house for Cayman Brac, I began to ponder the need to reinforce the existing stock, and to conceive affordable methods and gear. My structural engineering tasks included some monitoring of the builder's care with rugged but simple ties and diaphragms to meet Category 5 loads. That afforded opportunity to inspect Cayman buildings and talk to engineering colleagues there on the widespread inadequacies of the existing stock, even in these richest of the Caribbean islands. The design was finished and approved, and then came Category 5 Mitch in the fall of 1998.
It veered away from the Caymans at the last moment, missing them by 200 miles and stalling disastrously over the Bay Islands off Honduras. Studying photos of wind damage there, discussing weak points with the engineers pressed into better preparing the Caymans, and drawing upon decades of engineering work with many forms of house structures, I turned fully to the question of how to strengthen existing stock.
In the prior art as still practiced, hurricane-resisting retrofits remain uncommon, and favour only expensive houses. Designers approach each case as a one-off challenge. Until 1996 and later, patent files disclose very little focus on retrofit needs.
(The few so focused are mainly variations of steel cables, straps or nets deployed over the roof and anchored to the ground or foundation until the storm is over. One, US 5257483, 11/1993, Netek, expired, laboriously ties the lower end of each rafter to the wall by a strap screw-installed for the storm period.) In the absence of a practicable retrofit school of thought, or methods or gear, designers naturally think in terms of the galvanized steel straps that are well developed for new construction. First, however, soffits or ceilings have to be removed and, often, the exterior stucco or other cladding is stripped away to allow access to the roof rafters/trusses and the wall, respectively. The latter is often cut into to allow tying into the framing, or the reinforcing bars, ignoring the presence of "rough opening"
framings which intrinsically comprise embedded load-spreaders. All of this surgery is then covered over; the idea seems to be to hide all retrofits rather than leave them as "badges" of quality. Conventional hold-down straps are applied to each rafter, whereas wider spacing can work because of certain lengthwise spanning properties in most roofs.
Costs are high, with little market among "people's housing" despite the great need, and apparently little incentive to the busy engineers to develop that market and fill that need.
SPECIFICATION
This invention is a means of strengthening roofs against wind uplift forces.
It is conceived primarily for "retrofit" improvement of existing houses and other low-rise buildings. The need for such invention, and the drawbacks of the prior art that it avoids or overcomes, have been noted under Background. In particular, unlike current practices, the invention is conceived so that its permanent application entails little disruption of building or occupants, with little or no laborious "make good", and it employs a small number of anchors rather than many closely spaced ones to reduce labour still more and to present acceptable appearance. On the other hand the wide spacing entails greater loads requiring greater strengths than found in most conventional tie-down hardware; the invention considers and provides for such strength in its variations for differing roof wall types.
The invention comprises the widely spaced installation of anchor assemblies to hold down roofs, each anchor assembly consisting of a clasp affixed to the roof's overhang, from which a tension member extends down to a strong wall anchor set into the window surround structure or other suitably strong framing or structure in the exterior wall; that anchor completes the anchor assembly. The wide spacing of the anchor assemblies exploits the roof's bending strength and folded plate action along its length (in the direction transverse to the framing members in the roof plane), enabling each anchor assembly to hold down an area of roof considerably beyond the framing member or members directly clasped by the anchor assembly. The invention employs differing clasps and positions to accommodate the commonly encountered configurations and conditions of roof overhangs, as next specified.
In cases where the underside of the eave is not irreversibly closed in, ie.
there's no soffit closure or none that's difficult to remove and replace, then toothed "U"
clasps are pressed into certain of the roof framing members (normally rafters or trusses, hereinafter called "roof frames") where these extend to form the overhang (normally rafters or truss extensions) and are tied to the wall anchorages. Each U Clasp is preferentially formed of one-piece steel plate having two opposing side arms, each side arm extending upward and set sufficiently apart from the other to allow the pair of side arms to be pushed up over the opposing vertical sides of a protruding roof frame, loosely clasping it.
Each side arm is formed with a multitude of nail-like teeth punched out of the steel to point toward the opposing side arm, in the manner of conventional "truss plate" manufacture.
Mechanical pressure is applied to the positioned U Clasp, simultaneously forcing each side arm towards the roof frame, which drives the nail-like teeth into each vertical face of the roof frame and thereby strongly and very speedily clasps it. The established art includes hydraulic or pneumatic vise gear ideal for this purpose or readily adapted to it.
As an alternative form of U Clasp, the two side arms are made according to the invention with pre-punched holes (akin to an older form of truss plate) to receive nails or screws driven in situ, thereby reducing cost in manufacture and especially shipping (by allowing compact nesting), and serving do-it-yourself and other situations where labour time and costs are not paramount or specialized vise gear is not available.
This invention is a means of strengthening roofs against wind uplift forces.
It is conceived primarily for "retrofit" improvement of existing houses and other low-rise buildings. The need for such invention, and the drawbacks of the prior art that it avoids or overcomes, have been noted under Background. In particular, unlike current practices, the invention is conceived so that its permanent application entails little disruption of building or occupants, with little or no laborious "make good", and it employs a small number of anchors rather than many closely spaced ones to reduce labour still more and to present acceptable appearance. On the other hand the wide spacing entails greater loads requiring greater strengths than found in most conventional tie-down hardware; the invention considers and provides for such strength in its variations for differing roof wall types.
The invention comprises the widely spaced installation of anchor assemblies to hold down roofs, each anchor assembly consisting of a clasp affixed to the roof's overhang, from which a tension member extends down to a strong wall anchor set into the window surround structure or other suitably strong framing or structure in the exterior wall; that anchor completes the anchor assembly. The wide spacing of the anchor assemblies exploits the roof's bending strength and folded plate action along its length (in the direction transverse to the framing members in the roof plane), enabling each anchor assembly to hold down an area of roof considerably beyond the framing member or members directly clasped by the anchor assembly. The invention employs differing clasps and positions to accommodate the commonly encountered configurations and conditions of roof overhangs, as next specified.
In cases where the underside of the eave is not irreversibly closed in, ie.
there's no soffit closure or none that's difficult to remove and replace, then toothed "U"
clasps are pressed into certain of the roof framing members (normally rafters or trusses, hereinafter called "roof frames") where these extend to form the overhang (normally rafters or truss extensions) and are tied to the wall anchorages. Each U Clasp is preferentially formed of one-piece steel plate having two opposing side arms, each side arm extending upward and set sufficiently apart from the other to allow the pair of side arms to be pushed up over the opposing vertical sides of a protruding roof frame, loosely clasping it.
Each side arm is formed with a multitude of nail-like teeth punched out of the steel to point toward the opposing side arm, in the manner of conventional "truss plate" manufacture.
Mechanical pressure is applied to the positioned U Clasp, simultaneously forcing each side arm towards the roof frame, which drives the nail-like teeth into each vertical face of the roof frame and thereby strongly and very speedily clasps it. The established art includes hydraulic or pneumatic vise gear ideal for this purpose or readily adapted to it.
As an alternative form of U Clasp, the two side arms are made according to the invention with pre-punched holes (akin to an older form of truss plate) to receive nails or screws driven in situ, thereby reducing cost in manufacture and especially shipping (by allowing compact nesting), and serving do-it-yourself and other situations where labour time and costs are not paramount or specialized vise gear is not available.
The bottom of the U clasp, positioned under the bottom edge of the roof frame and connecting side arm to side arm, presents a space under said edge which comprises a grab receptacle for the tension member ( described below).
As an alternative means of securing the roof frames, especially to allow the clasp point (grab receptacle) to be adjusted to a point vertically over a suitable anchorage point in the wall below, and/or to allow each anchor's force to be shared between two roof frames, a yoke type of clasp can be installed according to the invention by drilling horizontally through the two roof frames to form two holes aligned with each other and inserting a strong bar or pipe to span between said frames, each end of the bar passing securely through one hole, and fitting or pre-fitting on the bar a ring or other suitable grab receptacle to which the tension member can be secured.
Normally, for reasons of strength, simplicity, economy and neatness of appearance, the U
Clasp or Yoke is positioned on the roof frame a little outboard of a point vertically above the exterior face of the wall, ie. where the roof begins to overhang the building proper.
However, especially for the purpose of strengthening a weak roof overhang against upward bending forces as well as tying down the roof proper, the U Clasp or Yoke can be positioned according to the invention at a point on the roof frame outboard of the exterior wall, toward the fascia, thereby reducing the cantilever span of the overhang as much as desired.
Especially in cases where the roof frames are not accessible from the underside of the overhang, anchoring the overhang can be accomplished according to the invention by grasping the roof fascia and abutting roof structure by means of a Flanged Clasp, comprising a metal plate folded to form an angle, one side becoming a face piece which is fitted down over the exterior of the fascia, the fold aligned at the edge of the roof, while the other side extends from the fold to form a flange which is inserted inward from the roof edge over the roof sheathing (normally under the shingles or tiles; the angle can be bent to suit the roof slope). The flange thereby presents a suitable area strongly nailed or screwed into the roof sheathing and normally into any roof frame thereunder; the face piece is similarly fastened to the fascia and normally through it into the end of a any roof frame abutting the fascia. The face piece contains a hole or hook-like device near its bottom edge suitably reinforced to form a grab receptacle for linking the Flanged Clasp and thereby a substantial area of the roof to anchorage in the wall below. The roof edge can be reinforced where deemed necessary by insertion of a metal load-spreader bar under the flange along the roof edge to strengthen the edge against crushing and help provide the order-of magnitude mechanical advantage of such a sharp corner in resisting the downward pull on the Flanged Clasp. Anchoring the overhang at the fascia is also a solution to the case where a weak overhang could be broken upward by wind uplift.
The wall anchor, the terminus of the anchor assembly, is normally set according to the invention into one of the structural members comprising the "rough opening"
surrounding and supporting a window or door: a vertical "buck" at either side of the opening, or horizontal "lintel" or "header" spanning across the top, or horizontal "sill"
As an alternative means of securing the roof frames, especially to allow the clasp point (grab receptacle) to be adjusted to a point vertically over a suitable anchorage point in the wall below, and/or to allow each anchor's force to be shared between two roof frames, a yoke type of clasp can be installed according to the invention by drilling horizontally through the two roof frames to form two holes aligned with each other and inserting a strong bar or pipe to span between said frames, each end of the bar passing securely through one hole, and fitting or pre-fitting on the bar a ring or other suitable grab receptacle to which the tension member can be secured.
Normally, for reasons of strength, simplicity, economy and neatness of appearance, the U
Clasp or Yoke is positioned on the roof frame a little outboard of a point vertically above the exterior face of the wall, ie. where the roof begins to overhang the building proper.
However, especially for the purpose of strengthening a weak roof overhang against upward bending forces as well as tying down the roof proper, the U Clasp or Yoke can be positioned according to the invention at a point on the roof frame outboard of the exterior wall, toward the fascia, thereby reducing the cantilever span of the overhang as much as desired.
Especially in cases where the roof frames are not accessible from the underside of the overhang, anchoring the overhang can be accomplished according to the invention by grasping the roof fascia and abutting roof structure by means of a Flanged Clasp, comprising a metal plate folded to form an angle, one side becoming a face piece which is fitted down over the exterior of the fascia, the fold aligned at the edge of the roof, while the other side extends from the fold to form a flange which is inserted inward from the roof edge over the roof sheathing (normally under the shingles or tiles; the angle can be bent to suit the roof slope). The flange thereby presents a suitable area strongly nailed or screwed into the roof sheathing and normally into any roof frame thereunder; the face piece is similarly fastened to the fascia and normally through it into the end of a any roof frame abutting the fascia. The face piece contains a hole or hook-like device near its bottom edge suitably reinforced to form a grab receptacle for linking the Flanged Clasp and thereby a substantial area of the roof to anchorage in the wall below. The roof edge can be reinforced where deemed necessary by insertion of a metal load-spreader bar under the flange along the roof edge to strengthen the edge against crushing and help provide the order-of magnitude mechanical advantage of such a sharp corner in resisting the downward pull on the Flanged Clasp. Anchoring the overhang at the fascia is also a solution to the case where a weak overhang could be broken upward by wind uplift.
The wall anchor, the terminus of the anchor assembly, is normally set according to the invention into one of the structural members comprising the "rough opening"
surrounding and supporting a window or door: a vertical "buck" at either side of the opening, or horizontal "lintel" or "header" spanning across the top, or horizontal "sill"
framing across the bottom of the opening. This setting firstly exploits the fact that each such structural member acts by itself and with its secured window or door to form a large load-spreader embedded in the wall, capable of resisting large forces acting vertically upward and also those acting upward and outward; secondly, that each such structural member normally presents an ample area into which the wall anchor can be set;
and thirdly that most exterior walls supporting roof frames are fitted with several such openings, spaced suitably close together to provide most or all of the anchorage points for the roof according to the invention. Further, an interior wall rather commonly joins to an exterior wall just where the windows are farther apart, and that junction offers another strengthened frame ready to accept a wall anchor. All of these or equivalent structures occur in walls framed in wood or light steel and in unit masonry walls and other common wall constructions. (Solutions for cases where the roof needs anchorage at points having no such opening or junction structure below them are described later.) The wall anchors themselves can be of conventional "off the shelf' hardware suitable for the wall material and the design load. Lag screw, toggle bolt, through bolt and expanding plug designs are some of the options. In the general case, the anchors may be set to strongest effect by drilling into the wall at a downward angle of 45 degrees or so, rather than horizontally inward normal to the wall plane, so that the axis of the wall anchor is more closely aligned with the tension member joining the clasp to the anchor, as next specified. The end of the anchor outboard of the wall is preferentially made or fitted with an "eye" or hook to serve as a grab receptacle for linking anchor to the clasp or yoke in the roof overhang above it.
The link between roof overhang and wall anchor is a tension member, which can be a rod or cable or other such slender structural member of high tensile capability fitted with a hook, angle or other such grab device at its top and bottom ends. The top grab device is inserted into the grab receptacle of the clasp or yoke which secures the roof overhang and the bottom grab device is inserted into the grab receptacle of the anchor set in the wall below. The grab devices or receptacles are made or fitted with clips or other closures to secure the linkage.
The grab devices, grab receptacles or closures can be designed for easy installation and removal of the tension members, according to the invention, allowing the tension members to be permanent fixtures or just temporarily installed to strengthen the roof for the duration of a storm.
Especially for the case where existing structures in the wall are too far apart to provide anchor points consistent with the roof s bending resisting capability to span between said anchor points under design wind uplift forces, said bending resistance can be augmented according to the invention by installing a roof reinforcing beam spanning between said anchor points or between the roof frames anchored at those points, which beam is restrained against uplift by said anchors or the anchored roof frames and is itself made fast to the roof structure along its length so that the roof structure is held down in turn by the beam.
The roof reinforcing beam can be formed by making the roof edge and fascia into a "T"
beam, in effect, by suitably nailing, screwing and/or gluing the roof sheathing to the fascia to become a "top flange" acting integrally with the fascia; or by further making the roof edge and fascia into a still stronger "C" (channel) beam by making the "T" as just stated and also securing a wood member along the fascia on the underside of the roof framing and providing shear connection between the wood member and the fascia, the fascia then becoming the web of the "C" beam and the wood member becoming its bottom flange.
The reinforcing beam can alternatively be a separate member mounted under the roof frames (under the overhang) and secured to them, or mounted along and against the exterior side of the fascia and fastened to it as well as through it to the abutting ends of the roof frames.
As a further alternative the reinforcing beam can be a separate member installed inside the roof space, aligned parallel to the fascia and placed as close to the exterior wall as the working room in the roof space will permit, and bearing down upon the ceiling joists to thereby hold down the roof frames and/or tied to the roof frames above.
Another solution for the case where the roof needs anchorage at a point where no strengthened opening or junction is located in a framed wall thereunder, is to install an intermediate anchor exploiting the wall's exterior sheathing's axial strength to restrain the anchor against vertically upward forces. The intermediate anchor comprises a stiff metal bar bent into a "J", the bottom part of which is inserted through a horizontal slot cut through the sheathing (cladding having been removed as necessary) into the wall cavity.
Said bottom part, hooking slightly upward along the interior surface of the sheathing, is pushed upward to bear snugly against the underside of the top edge of the slot cut in the sheathing. The J's upright piece remains outside the sheathing and is nailed or screwed to it, and is made or fitted with a grab receptacle to complete the wall anchor.
In the case where said intermediate anchor must resist a significant outward component of force as well as the substantial vertically upward component (as in the configurations where the clasp is at the fascia or otherwise well outboard of the exterior wall), said J
anchor remains as described to transfer the vertically upward component of force into the sheathing, while being supplemented to transfer the outward component of force by means of a tie such as a long lag screw or bolt which extends through the wall and fastens into a lateral beam positioned indoors against the interior finish.
The lateral beam is sized and positioned to transfer the outward component of force from the tie into the two nearest studs (in the case of a framed wall ) or into a structurally sufficient area of wall (in the case of unit masonry construction, for example). The lateral beam can be an existing mantel, counter, shelf or stair stringer or the like, or can be a shelf or wainscot piece or the like installed for the purpose.
Notwithstanding the invention's first orientation toward the anchoring of a roof by securing its eave or overhang, an alternative orientation according to the invention is especially useful where the roof frames are exposed to the indoor space below (as sometimes occurs with flat roofs and cathedral ceilings): a U Clasp grasps a roof frame inboard of a point vertically above the indoor surface plane of the wall bearing the roof frame; the wall anchor below is set into a strengthened frame or strong wall structure such as a window lintel (just as described above but penetrating the wall from the indoor surface outward); the tension member links clasp to anchor. The advantages of widely spaced anchor assemblies are exploited, with the further advantage that all the work can be done indoors. (If and where roof reinforcing beams are needed as described above, they would be installed in the overhang or fascia area where needed, requiring ladder or scaffold work outdoors.) Notwithstanding the invention's first orientation toward anchorage in the exterior wall structure, an alternative according to the invention can be useful where balcony or deck structures are present below the roof overhang: the tension members extend essentially vertically downward from clasp positions on the roof frame or fascia suitably outboard of the exterior wall, and are anchored into suitably strong points on said balcony or deck structures or their railings.
In drawings illustrating embodiments of the invention: Figure 1 is an exterior wall elevation extending up as a section through the roof frames bearing thereon, serving to suggest generalities of the invention including the wide spacing of the anchor assemblies;
Figures 2, 3 and 4 are vertical sections through roof overhangs and adjoining wall thereunder, at or within wall openings, illustrating preferred anchor assemblies and their normal placement; Figure 5 is a perspective sketch looking up at a portion of a roof overhang to show the preferred roof clasps in more detail; Figure 6 is a vertical section of wall suggesting alternative wall anchorages; Figure 7 is a vertical section through a wall-overhang illustrating an alternative indoor placement of the whole anchor assembly.
In all drawings, like numbers denote like objects. 1 denotes a U Clasp securing an individual roof framing member while 1 (y) denotes a Yoke type of clasp securing two; 2 denotes a tension member securing the clasp to 3, the wall anchor; 1,2,3 together denotes a whole anchor assembly. In Figure 1, the anchor assemblies l, 2, 3 sketched in solid lines suggest installations where the maximum permissible spacing of anchorages along an overhang is four roof framing spaces, as if the example roof is strong enough to span that distance between anchor points. Anchorages can be made into the normally strengthened wall structures surrounding a door or window, 4. As a different example, assuming the roof's bending strength across its roof frames members were sufficient to span just three framing spaces, the dotted line anchor assemblies 1 (y), 2, 3 would be needed along with the aforesaid solid line anchor assemblies. Anchor assemblies 1 (y), 2, 3 here illustrate that the assembly on the left is able to reach the roof frame member on its left and also the window buck or (lintel end) vertically below, while the assembly on the right is able to reach vertically down to anchor into the strengthened structure 5 below (vertical dotted lines), despite the offset of anchor point from individual roof frame in each case. The vertical dotted lines 5 suggest a junction where a partition wall frames into or is secured into the exterior wall, so that Figure 1 illustrates all the normally strengthened wall areas according to the invention: around openings, and at such junctions. Finally, the horizontal dotted lines 6 in Figure 1 suggest the spans of roof reinforcing beams, were these to be called upon as the invention's alternative solution for the case where the existing anchor points are too far apart for the existing roof's bending strength between anchors.
Figure 2 illustrates the preferred anchor assembly and its normal usage in some detail.
The U Clasp, 1, clasps the roof frame just outboard of the exterior wall. The tension member 2 connecting the U Clasp to the wall anchor 3 is here a rod, with its ends bent to form grabs 7; the top grab being inserted into the grab receptacle 8 formed by the bottom part of the U Clasp, the bottom grab into the grab receptacle 8 of the wall anchor 3, which is here suggested as a lag screw into a wood lintel. A retainer clip 9 locks the top grab in place (the bottom closure is not shown). A turnbuckle or like device 10 allows the anchor assembly to be tightened as desired.
Since there is no working room in this common case to angle the wall anchor 3 downward to align it with the tension member, it is angled sharply upward into the lintel to align said two components as much as practicable. Even so, the eccentric loading will cause a stress concentration where the lag screw enters the lintel, so that in some design conditions a spreader angle 11 (essentially an ample washer) would be inserted.
The inset to the right of the main section is an anchor detail 3 where the lintel is formed of concrete as is fairly common in unit masonry walls; in this example an expansive-shank bolt is suggested as the anchor.
Two alternative ways of installing a roof reinforcing beam 6 are also shown in Figure 2, one or the other being installed where such reinforcement is the preferred solution where practicable anchor points are too far apart for the roof's ability to span between them, as discussed above. The "C" beam configuration is illustrated as the fascia-strengthening solution for this, while a steel "I" beam is shown as an example of the roof space option.
Figure 3 illustrates the positioning of the U Clasp 1 well outboard of the wall's exterior plane, especially useful where the overhang is otherwise too weak in bending strength to resist design uplift forces.
Figure 4 illustrates the use of the Flanged Clasp 12 securing the roof edge at the fascia, again useful where the overhang is weak against uplift but especially advantageous where a closed soffit obstructs access to the roof frames. A spreader bar 13 is inserted under the flange along the roof edge to strengthen the edge against crushing and help provide the order-of magnitude mechanical advantage of such a sharp corner in resisting the downward pull on the Flanged Clasp.
Figure 5 gives more detail on the preferred U Clasp and Yoke types of roof clasps, 1 and 1 (y) respectively, showing means of providing grab receptacles 8 for each type. The inset sketch of the U Clasp 1 suggests the form using nail-like punched teeth, the preferred form for speed and efficiency.
Figure 6 illustrates a preferred solution for the case where a wall anchor 3 needs to be placed in a strongly sheathed framed wall at a point where there's no structure to receive it. Two solutions are here, only one shown in full. First, in the usual case where the tension member 2 pulls straight upward (not shown), the bottom part of the strong metal J
Anchor 14 is inserted through a slot cut in the sheathing (plywood or OSB, oriented strand board, are common and suitably strong examples), the hook-like bottom bearing up against the underside of the top of the slot, and the exterior part screwed to the sheathing to complete the anchorage. (Here, the sketch's orientation with the outdoors on the left results in a backward J, unfortunately.) However, where there's a considerable outward component of force through the tension member as illustrated, the J
piece is still installed as stated and shown, but a transverse tie member 15 is installed and secured through an indoor spreader beam 16, here suggested as an added shelf.
Figure 7 suggests the completely indoor embodiment of the invention which can be advantageously used where the roof frames are exposed to and accessible from the building interior.
In the preferred embodiments, the anchor assemblies are formed of galvanized steel or other suitably strong, non-corrosive metal. Quality, dimensions and detailing are determined as appropriate for the design loads. (I have found that anchor assemblies as described above can readily be designed for short term design loads of 1.5 to 3 kips, for example, such anchoring loads being in the range encountered in typical building configurations such as suggested in Figure 1. The anchor assembly's deformability under dynamic load can be designed relative to that of the roof s existing tie-down provisions, so that uplift loads can be shared between the added anchors and the existing provisions in an approximately predictable and economically advantageous manner. Of course, a test program could furnish more knowledge about the properties of the anchor assemblies in various constructions, and thus allow finer, more economical design for individually tailored cases as well as mass applications, but I have found that the engineering can be done usefully now, with present knowledge of loads, material properties and "limit state"
design methods for short term loads.) Modifications and variations of the present invention are of course possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
and thirdly that most exterior walls supporting roof frames are fitted with several such openings, spaced suitably close together to provide most or all of the anchorage points for the roof according to the invention. Further, an interior wall rather commonly joins to an exterior wall just where the windows are farther apart, and that junction offers another strengthened frame ready to accept a wall anchor. All of these or equivalent structures occur in walls framed in wood or light steel and in unit masonry walls and other common wall constructions. (Solutions for cases where the roof needs anchorage at points having no such opening or junction structure below them are described later.) The wall anchors themselves can be of conventional "off the shelf' hardware suitable for the wall material and the design load. Lag screw, toggle bolt, through bolt and expanding plug designs are some of the options. In the general case, the anchors may be set to strongest effect by drilling into the wall at a downward angle of 45 degrees or so, rather than horizontally inward normal to the wall plane, so that the axis of the wall anchor is more closely aligned with the tension member joining the clasp to the anchor, as next specified. The end of the anchor outboard of the wall is preferentially made or fitted with an "eye" or hook to serve as a grab receptacle for linking anchor to the clasp or yoke in the roof overhang above it.
The link between roof overhang and wall anchor is a tension member, which can be a rod or cable or other such slender structural member of high tensile capability fitted with a hook, angle or other such grab device at its top and bottom ends. The top grab device is inserted into the grab receptacle of the clasp or yoke which secures the roof overhang and the bottom grab device is inserted into the grab receptacle of the anchor set in the wall below. The grab devices or receptacles are made or fitted with clips or other closures to secure the linkage.
The grab devices, grab receptacles or closures can be designed for easy installation and removal of the tension members, according to the invention, allowing the tension members to be permanent fixtures or just temporarily installed to strengthen the roof for the duration of a storm.
Especially for the case where existing structures in the wall are too far apart to provide anchor points consistent with the roof s bending resisting capability to span between said anchor points under design wind uplift forces, said bending resistance can be augmented according to the invention by installing a roof reinforcing beam spanning between said anchor points or between the roof frames anchored at those points, which beam is restrained against uplift by said anchors or the anchored roof frames and is itself made fast to the roof structure along its length so that the roof structure is held down in turn by the beam.
The roof reinforcing beam can be formed by making the roof edge and fascia into a "T"
beam, in effect, by suitably nailing, screwing and/or gluing the roof sheathing to the fascia to become a "top flange" acting integrally with the fascia; or by further making the roof edge and fascia into a still stronger "C" (channel) beam by making the "T" as just stated and also securing a wood member along the fascia on the underside of the roof framing and providing shear connection between the wood member and the fascia, the fascia then becoming the web of the "C" beam and the wood member becoming its bottom flange.
The reinforcing beam can alternatively be a separate member mounted under the roof frames (under the overhang) and secured to them, or mounted along and against the exterior side of the fascia and fastened to it as well as through it to the abutting ends of the roof frames.
As a further alternative the reinforcing beam can be a separate member installed inside the roof space, aligned parallel to the fascia and placed as close to the exterior wall as the working room in the roof space will permit, and bearing down upon the ceiling joists to thereby hold down the roof frames and/or tied to the roof frames above.
Another solution for the case where the roof needs anchorage at a point where no strengthened opening or junction is located in a framed wall thereunder, is to install an intermediate anchor exploiting the wall's exterior sheathing's axial strength to restrain the anchor against vertically upward forces. The intermediate anchor comprises a stiff metal bar bent into a "J", the bottom part of which is inserted through a horizontal slot cut through the sheathing (cladding having been removed as necessary) into the wall cavity.
Said bottom part, hooking slightly upward along the interior surface of the sheathing, is pushed upward to bear snugly against the underside of the top edge of the slot cut in the sheathing. The J's upright piece remains outside the sheathing and is nailed or screwed to it, and is made or fitted with a grab receptacle to complete the wall anchor.
In the case where said intermediate anchor must resist a significant outward component of force as well as the substantial vertically upward component (as in the configurations where the clasp is at the fascia or otherwise well outboard of the exterior wall), said J
anchor remains as described to transfer the vertically upward component of force into the sheathing, while being supplemented to transfer the outward component of force by means of a tie such as a long lag screw or bolt which extends through the wall and fastens into a lateral beam positioned indoors against the interior finish.
The lateral beam is sized and positioned to transfer the outward component of force from the tie into the two nearest studs (in the case of a framed wall ) or into a structurally sufficient area of wall (in the case of unit masonry construction, for example). The lateral beam can be an existing mantel, counter, shelf or stair stringer or the like, or can be a shelf or wainscot piece or the like installed for the purpose.
Notwithstanding the invention's first orientation toward the anchoring of a roof by securing its eave or overhang, an alternative orientation according to the invention is especially useful where the roof frames are exposed to the indoor space below (as sometimes occurs with flat roofs and cathedral ceilings): a U Clasp grasps a roof frame inboard of a point vertically above the indoor surface plane of the wall bearing the roof frame; the wall anchor below is set into a strengthened frame or strong wall structure such as a window lintel (just as described above but penetrating the wall from the indoor surface outward); the tension member links clasp to anchor. The advantages of widely spaced anchor assemblies are exploited, with the further advantage that all the work can be done indoors. (If and where roof reinforcing beams are needed as described above, they would be installed in the overhang or fascia area where needed, requiring ladder or scaffold work outdoors.) Notwithstanding the invention's first orientation toward anchorage in the exterior wall structure, an alternative according to the invention can be useful where balcony or deck structures are present below the roof overhang: the tension members extend essentially vertically downward from clasp positions on the roof frame or fascia suitably outboard of the exterior wall, and are anchored into suitably strong points on said balcony or deck structures or their railings.
In drawings illustrating embodiments of the invention: Figure 1 is an exterior wall elevation extending up as a section through the roof frames bearing thereon, serving to suggest generalities of the invention including the wide spacing of the anchor assemblies;
Figures 2, 3 and 4 are vertical sections through roof overhangs and adjoining wall thereunder, at or within wall openings, illustrating preferred anchor assemblies and their normal placement; Figure 5 is a perspective sketch looking up at a portion of a roof overhang to show the preferred roof clasps in more detail; Figure 6 is a vertical section of wall suggesting alternative wall anchorages; Figure 7 is a vertical section through a wall-overhang illustrating an alternative indoor placement of the whole anchor assembly.
In all drawings, like numbers denote like objects. 1 denotes a U Clasp securing an individual roof framing member while 1 (y) denotes a Yoke type of clasp securing two; 2 denotes a tension member securing the clasp to 3, the wall anchor; 1,2,3 together denotes a whole anchor assembly. In Figure 1, the anchor assemblies l, 2, 3 sketched in solid lines suggest installations where the maximum permissible spacing of anchorages along an overhang is four roof framing spaces, as if the example roof is strong enough to span that distance between anchor points. Anchorages can be made into the normally strengthened wall structures surrounding a door or window, 4. As a different example, assuming the roof's bending strength across its roof frames members were sufficient to span just three framing spaces, the dotted line anchor assemblies 1 (y), 2, 3 would be needed along with the aforesaid solid line anchor assemblies. Anchor assemblies 1 (y), 2, 3 here illustrate that the assembly on the left is able to reach the roof frame member on its left and also the window buck or (lintel end) vertically below, while the assembly on the right is able to reach vertically down to anchor into the strengthened structure 5 below (vertical dotted lines), despite the offset of anchor point from individual roof frame in each case. The vertical dotted lines 5 suggest a junction where a partition wall frames into or is secured into the exterior wall, so that Figure 1 illustrates all the normally strengthened wall areas according to the invention: around openings, and at such junctions. Finally, the horizontal dotted lines 6 in Figure 1 suggest the spans of roof reinforcing beams, were these to be called upon as the invention's alternative solution for the case where the existing anchor points are too far apart for the existing roof's bending strength between anchors.
Figure 2 illustrates the preferred anchor assembly and its normal usage in some detail.
The U Clasp, 1, clasps the roof frame just outboard of the exterior wall. The tension member 2 connecting the U Clasp to the wall anchor 3 is here a rod, with its ends bent to form grabs 7; the top grab being inserted into the grab receptacle 8 formed by the bottom part of the U Clasp, the bottom grab into the grab receptacle 8 of the wall anchor 3, which is here suggested as a lag screw into a wood lintel. A retainer clip 9 locks the top grab in place (the bottom closure is not shown). A turnbuckle or like device 10 allows the anchor assembly to be tightened as desired.
Since there is no working room in this common case to angle the wall anchor 3 downward to align it with the tension member, it is angled sharply upward into the lintel to align said two components as much as practicable. Even so, the eccentric loading will cause a stress concentration where the lag screw enters the lintel, so that in some design conditions a spreader angle 11 (essentially an ample washer) would be inserted.
The inset to the right of the main section is an anchor detail 3 where the lintel is formed of concrete as is fairly common in unit masonry walls; in this example an expansive-shank bolt is suggested as the anchor.
Two alternative ways of installing a roof reinforcing beam 6 are also shown in Figure 2, one or the other being installed where such reinforcement is the preferred solution where practicable anchor points are too far apart for the roof's ability to span between them, as discussed above. The "C" beam configuration is illustrated as the fascia-strengthening solution for this, while a steel "I" beam is shown as an example of the roof space option.
Figure 3 illustrates the positioning of the U Clasp 1 well outboard of the wall's exterior plane, especially useful where the overhang is otherwise too weak in bending strength to resist design uplift forces.
Figure 4 illustrates the use of the Flanged Clasp 12 securing the roof edge at the fascia, again useful where the overhang is weak against uplift but especially advantageous where a closed soffit obstructs access to the roof frames. A spreader bar 13 is inserted under the flange along the roof edge to strengthen the edge against crushing and help provide the order-of magnitude mechanical advantage of such a sharp corner in resisting the downward pull on the Flanged Clasp.
Figure 5 gives more detail on the preferred U Clasp and Yoke types of roof clasps, 1 and 1 (y) respectively, showing means of providing grab receptacles 8 for each type. The inset sketch of the U Clasp 1 suggests the form using nail-like punched teeth, the preferred form for speed and efficiency.
Figure 6 illustrates a preferred solution for the case where a wall anchor 3 needs to be placed in a strongly sheathed framed wall at a point where there's no structure to receive it. Two solutions are here, only one shown in full. First, in the usual case where the tension member 2 pulls straight upward (not shown), the bottom part of the strong metal J
Anchor 14 is inserted through a slot cut in the sheathing (plywood or OSB, oriented strand board, are common and suitably strong examples), the hook-like bottom bearing up against the underside of the top of the slot, and the exterior part screwed to the sheathing to complete the anchorage. (Here, the sketch's orientation with the outdoors on the left results in a backward J, unfortunately.) However, where there's a considerable outward component of force through the tension member as illustrated, the J
piece is still installed as stated and shown, but a transverse tie member 15 is installed and secured through an indoor spreader beam 16, here suggested as an added shelf.
Figure 7 suggests the completely indoor embodiment of the invention which can be advantageously used where the roof frames are exposed to and accessible from the building interior.
In the preferred embodiments, the anchor assemblies are formed of galvanized steel or other suitably strong, non-corrosive metal. Quality, dimensions and detailing are determined as appropriate for the design loads. (I have found that anchor assemblies as described above can readily be designed for short term design loads of 1.5 to 3 kips, for example, such anchoring loads being in the range encountered in typical building configurations such as suggested in Figure 1. The anchor assembly's deformability under dynamic load can be designed relative to that of the roof s existing tie-down provisions, so that uplift loads can be shared between the added anchors and the existing provisions in an approximately predictable and economically advantageous manner. Of course, a test program could furnish more knowledge about the properties of the anchor assemblies in various constructions, and thus allow finer, more economical design for individually tailored cases as well as mass applications, but I have found that the engineering can be done usefully now, with present knowledge of loads, material properties and "limit state"
design methods for short term loads.) Modifications and variations of the present invention are of course possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
Claims (17)
1. In a house or other small building, a method of strengthening the roof against wind uplift by anchoring the overhang at widely spaced intervals into existing structures in the wall below, wherein - "widely spaced" means a distance between anchorage points of at least twice the distance between those roof framing members (roof frames") which terminate in the overhang;
- existing structures in the wall are the doubled-up frames forming the "rough opening" containing windows or doors, including vertical bucks, horizontal lintels, headers and rough sills; mullions; vertical junctions between exterior and interior walls; these and equivalent structures in, or other suitably strong portions of, walls framed in wood or light steel or unit masonry walls or other wall constructions.
- existing structures in the wall are the doubled-up frames forming the "rough opening" containing windows or doors, including vertical bucks, horizontal lintels, headers and rough sills; mullions; vertical junctions between exterior and interior walls; these and equivalent structures in, or other suitably strong portions of, walls framed in wood or light steel or unit masonry walls or other wall constructions.
2. Especially where the roof frames are accessible from the underside of the overhang, a method and apparatus according to Claim 1 wherein certain roof framing members are grasped at points in their overhanging lengths by means of a U shaped clasp, each such "U Clasp" comprised of a one-piece metal plate having two opposing side arms forming a U, each side arm extending upward and set sufficiently apart from the other to allow the pair of side arms to be pushed up over the opposing vertical sides of a protruding roof frame, loosely clasping said frame; each side arm being formed with a multitude of nail-like teeth punched out of the steel to point toward the opposing side arm; and pressure then being applied to the positioned U Clasp to simultaneously force each side arm towards the roof frame, thereby driving the nail-like teeth into each vertical side of the roof frame and strongly grasping it; or, the U
Clasp being made with pre-punched holes in the side arms (said holes replacing the nail-like teeth) to admit nails or screws which are driven through the holes and into the roof frame and thereby strongly grasp it; and, in which U Clasp, the bottom part of the U connecting the two side arms encloses a space below the bottom edge of the roof frame, said bottom part and space serving as a grab receptacle for linking the U
Clasp and thereby the roof frame member to anchorage in the wall below.
Clasp being made with pre-punched holes in the side arms (said holes replacing the nail-like teeth) to admit nails or screws which are driven through the holes and into the roof frame and thereby strongly grasp it; and, in which U Clasp, the bottom part of the U connecting the two side arms encloses a space below the bottom edge of the roof frame, said bottom part and space serving as a grab receptacle for linking the U
Clasp and thereby the roof frame member to anchorage in the wall below.
3. An alternative method and apparatus of securing the roof frames, according to Claims 1 and 2, whereby a Yoke is installed by drilling horizontally through two adjacent roof frames to create two holes aligned with each other and inserting a strong bar or pipe to span between and act as a yoke holding down said roof frames, each end of the bar passing securely through one hole, and fitting or pre-fitting on the bar a ring or other suitable grab receptacle for linking the Yoke and thereby its two clasped roof frames to anchorage in the wall below.
4. According to Claims 1 to 4, and especially for simplicity, strength and economy, a method wherein the U Clasp or Yoke is positioned on the roof frame or frames just a little outboard of a point vertically above the exterior face of the wall, ie.
where the roof overhang begins.
where the roof overhang begins.
5. According to Claims 1 to 4, and especially for the purpose of strengthening a weak roof overhang against upward bending forces as well as tying down the roof proper, a method of positioning the U clasp or Yoke on the roof frame or frames at a point substantially outboard of the exterior wall, toward the fascia, thereby reducing the cantilever span of the overhang.
6. Especially where the roof frames are not accessible from the underside of the overhang, a method and apparatus of anchoring the overhang according to Claim 1 by grasping the roof fascia and abutting roof structure by means of a Flanged Clasp, comprising a metal plate folded to form an angle, one side becoming a flat face piece which fits down from the edge of the roof over the exterior of the fascia, the other side extending from the fold at the top of the face piece to form a flat flange which extends inward from the roof edge over the roof sheathing (normally under the shingles or tiles); the flange thereby presenting a suitable area which is strongly nailed or screwed into the roof sheathing and normally into any roof frame thereunder; the face piece similarly fastened to the fascia and normally through it into the end of any roof frame abutting the fascia; the face piece containing a hole or hook-like device near its bottom edge suitably reinforced to form a grab receptacle for linking the flange and thereby a substantial area of the roof to anchorage in the wall below; and the roof edge being reinforced where and to the extent deemed necessary by insertion of a metal load-spreader bar under the flange along the roof edge.
7. A method and apparatus according to Claim 1, wherein the wall anchors comprise hardware suitable for the wall material and the design load, such as lag screw, toggle bolt, through bolt and or expanding plug design; the end of each anchor outboard of the wall being made or fitted with an "eye" or hook to serve as a grab receptacle for the purpose of linking the anchor to the grab receptacle in the clasp or yoke in the overhang above it.
8. A method and apparatus according to Claims 1, 2 and 3, wherein the linking of roof overhang to wall anchorage is by means of a tension member, which can be a rod or cable or other such slender structural member of high tensile capability; said tension member being fitted with a hook, angle or other such grab device at its top and bottom extremities; the top grab device being inserted into the grab receptacle of the clasp or yoke which secures the roof overhang and the bottom grab device being inserted into the grab receptacle which forms part of the anchor set in the wall below;
the grab devices or receptacles being made or fitted with clips or other closures to keep the linkage secure.
the grab devices or receptacles being made or fitted with clips or other closures to keep the linkage secure.
9. A method according to Claim 8 whereby the grab devices, grab receptacles or closures are designed for easy installation and removal of the tension members, allowing them to be permanent fixtures or just temporarily installed to strengthen the roof for the duration of a storm.
10. A method following Claim 1, especially for the case where existing structures in the wall are too far apart to provide anchor points consistent with the roof's bending resisting capability to span between said anchor points under design wind uplift forces, wherein said bending resistance capability is augmented by installing a reinforcing beam spanning between said anchor points or between the roof frames anchored at those points, which beam is restrained against uplift by said anchors or the anchored roof frames and is itself made fast to the roof structure along its length so that the roof structure is held down in turn by the beam.
11. A method according to Claim 10 wherein the reinforcing beam is formed by making the roof edge and fascia into a "T" beam, in effect, by suitably nailing, screwing and/or gluing the roof sheathing to the fascia to become a top flange acting integrally with the fascia; or further making the roof edge and fascia into a still stronger "C"
channel beam by making the "T" as just stated and also securing a wood member along the fascia on the underside of the roof frames and providing shear connection between the wood member and the fascia, the fascia then becoming the web of the "C" beam and the wood member becoming its bottom flange.
channel beam by making the "T" as just stated and also securing a wood member along the fascia on the underside of the roof frames and providing shear connection between the wood member and the fascia, the fascia then becoming the web of the "C" beam and the wood member becoming its bottom flange.
12. A method according to Claim 10 wherein the reinforcing beam is a separate member mounted under the roof frames and secured to them, or mounted along and against the exterior side of the fascia and fastened to it as well as through it to the abutting ends of the roof frames.
13. A method according to Claim 10 wherein the reinforcing beam is a separate member installed inside the roof space aligned parallel to the fascia and placed as close to the exterior wall line as the working room in the roof space will permit, and bearing down upon the ceiling joists to hold down the roof frames and/or tied to the roof frames above.
14. A method and apparatus following Claim 1, again especially for the case where existing structures in a framed wall construction are too far apart to provide anchor points consistent with the roof's bending resisting capability to span between said anchor points under design wind uplift forces, wherein the framed wall is fitted with an intermediate anchor exploiting the wall's exterior sheathing's axial strength to restrain the anchor against vertically upward forces; the intermediate anchor incorporating a stiff metal bar bent into a "J", the bottom part of which is inserted through a horizontal slot cut through the sheathing (cladding having been removed as necessary) into the wall cavity, hooking slightly upward along the interior surface of the sheathing and pushed upward to bear against the underside of the top edge of the slot cut in the sheathing; the J's upright piece remaining outside the sheathing and nailed or screwed to it, and itself incorporating or fitted with a grab receptacle to complete the wall anchor.
15. A method and apparatus according to Claim 14, in the case where said intermediate anchor must resist a significant outward component of force as well as the substantial vertically upward component (as in the configurations in Claims 5 and 6), wherein the J anchor remains as described to transfer the vertically upward component of force into the sheathing, while it is supplemented to transfer the outward component of force by means of a tension tie such as a long lag screw or bolt which extends through the wall and fastens into a lateral beam or load spreader positioned indoors against the interior finish, said beam transferring that outward component of force back into the two nearest frames (in the case of a framed wall) or into a structurally adequate area of wall (in the case of unit masonry construction, for example);
said beam or load spreader being an existing mantel, counter, shelf or stair stringer or the like or being a shelf or wainscot piece or the like installed for the purpose.
said beam or load spreader being an existing mantel, counter, shelf or stair stringer or the like or being a shelf or wainscot piece or the like installed for the purpose.
16. Following Claims 1, 2, 3, 7 and 8, especially where the roof frames members are exposed to the indoor space below (as occurs for example with flat roofs and cathedral ceilings), and notwithstanding the first orientation of the invention toward anchoring of a roof by securing its eave or overhang, a method and apparatus wherein a U Clasp grasps a roof frame inboard of a point vertically above the indoor surface plane of the wall bearing the roof member; the wall anchor below is set into a strengthened frame such as a window lintel (just as described above but penetrating the wall from the indoor surface outward); the tension member links clasp to anchor.
17. A method following Claims 1, 5 and 6 wherein the tension members extend essentially vertically downward from the outboard clasp positions on the roof framing member or fascia, and are anchored into suitably strong points on a balcony or deck or railing of same.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002287797A CA2287797A1 (en) | 1999-10-12 | 1999-10-12 | Anchoring overhangs to walls to strengthen roofs against hurricanes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002287797A CA2287797A1 (en) | 1999-10-12 | 1999-10-12 | Anchoring overhangs to walls to strengthen roofs against hurricanes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2287797A1 true CA2287797A1 (en) | 2001-04-12 |
Family
ID=4164520
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002287797A Abandoned CA2287797A1 (en) | 1999-10-12 | 1999-10-12 | Anchoring overhangs to walls to strengthen roofs against hurricanes |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2287797A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2453865A (en) * | 2007-10-20 | 2009-04-22 | Jonathan Francis Andrew Cooke | Demountable shelter |
| US9995054B1 (en) * | 2017-07-17 | 2018-06-12 | Robert Nellis | Pool enclosure anchor kit |
| CN112627349A (en) * | 2020-12-16 | 2021-04-09 | 澧县红似火新型建材有限责任公司 | Combined spliced steel structure house outer eave device |
-
1999
- 1999-10-12 CA CA002287797A patent/CA2287797A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2453865A (en) * | 2007-10-20 | 2009-04-22 | Jonathan Francis Andrew Cooke | Demountable shelter |
| GB2453865B (en) * | 2007-10-20 | 2009-12-23 | Jonathan Francis Andrew Cooke | Shelter |
| US9995054B1 (en) * | 2017-07-17 | 2018-06-12 | Robert Nellis | Pool enclosure anchor kit |
| CN112627349A (en) * | 2020-12-16 | 2021-04-09 | 澧县红似火新型建材有限责任公司 | Combined spliced steel structure house outer eave device |
| CN112627349B (en) * | 2020-12-16 | 2022-01-21 | 青岛亿立钢构工程有限公司 | Combined spliced steel structure house outer eave device |
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