GB2356419A

GB2356419A - Threshold door sill drainage unit having a flat upper surface defined by means of a flush removable cover

Info

Publication number: GB2356419A
Application number: GB9927222A
Authority: GB
Inventors: Gary Andrew Hatcher
Original assignee: Aco Technologies PLC
Current assignee: Aco Technologies PLC
Priority date: 1999-11-17
Filing date: 1999-11-17
Publication date: 2001-05-23
Anticipated expiration: 2019-11-17
Also published as: GB2356419B; GB9927222D0

Abstract

A threshold door sill drainage unit (2) comprises an elongate block having two ends (4 and 6), a base (8), front and back side walls (10 and 12), a substantially horizontal upper surface (14) and an interior drainage cavity (16). A slot (18), defined in the upper surface, allows water to enter the drainage cavity and at least one opening (20) in the front side wall (10) allows the water to escape. A flush fitting removable cover plate (44) is provided to enable access to the drainage cavity (16) for cleaning purposes. At least one end of the unit (4) opens directly into the drainage cavity and is sealed by a removable end plug (60), allowing the unit to be cut to the required length. A water bar (30) may be cast into the upper surface of the unit, rearwardly of the slot (18), and preferably extends across the whole width of the sill to cooperate with a notched door frame to prevent water seeping past the edges of the bar. Alternatively, a polypropylene strip may be provided on the upper surface, in the same position as the water bar, in order to secure a proprietary sealing strip.

Description

2356419 Door sill drainage unit

Background of the Invention

The present invention relates to threshold or door sill drainage units and, in particular, to such a unit, which is intended to be installed below a door in place of the traditional door 5 sill.

Prior Art

Normally a door sill is raised above the level of the external ground surface in order to prevent the entry of water into the building. Water may also enter a building as wind driven rain and to. prevent this a water bar is normally fitted in a wooden or metal doorstep sill. This water bar is a vertically upstanding bar extending across the door opening. It typically seats against a rebate formed in the underside of the door when the door is closed. Any water blown underneath the door hits the bar and is drained down the slope of the sill away from the interior of the building. A number of proprietary threshold seals are also available which fulfil the same function as the water bar and can also act as draft excluders.

Such prior art designs are effective but result in a considerable step at the threshold of the building, which creates an obstacle to the entry of the disabled and particularly those who are confined to wheelchairs. In the United Kingdom, Building Regulations now stipulate that all new homes are to be built with a "level threshold" in order to provide easy and safe access for people in wheelchairs from alighting from a vehicle through to entry into the building. This new regulation brings the domestic situation more in line with commercial and retail buildings.

GB-A-2 299 607 discloses a drainage unit for a door sill which provide such a level threshold. An elongate slot which communicates via internal drainage channels with 2 drainage outlets formed at a lower level in the front surface of the unit is provided. The slot is positioned in front of a water bar in order to receive driving rain which has been deflected by the water bar. It is proposed that such a unit be cast as a single fixed-length unit from polymer concrete, rigid plastics, natural concrete or reconstituted stone.

Technical Problem Such a door sill drainage unit still suffers from a number of technical problems although it does provide the required level threshold. Firstly, it is necessary for the unit to be of the required length for the door opening. Secondly, it was still possible for water to seep round the sides of the water bar. Thirdly, it is virtually impossible to clear away any trapped debris from within such a door sill.

Solution of the Invention In accordance with the invention there is provided a threshold door sill drainage unit for providing a level threshold that comprises an elongate block having two ends, a base, front and back side walls, a substantially horizontal upper surface and an interior drainage cavity, a slot being defined in the said upper surface communicating with the drainage cavity, and at least one opening in the front side wall communicating with the drainage cavity, characterised in that at least part of the of the upper surface is defined by means of a flush removable cover providing access to the drainage cavity, and in that.the ends are open directly into the drainage cavity and removable ends plugs are provided to seal each end of the drainage cavity.

Advantages of the Invention The use of a flush removable cover allows convenient access to the drainage cavity for cleaning. This prevents the build up of stagnant water or material that could give rise to unpleasant odours. Flush fitting is necessary in order to maintain the level threshold.

3 The provision of at least one open end to the unit allows its length to be adjusted. Preferably both ends are left open so that an equal amount can be cut away from each end of the unit to maintain symmetry- In a preferred embodiment the removable end plugs can be moulded plastics inserts.

Brief Description of the Drawings

In order that the invention may be well understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which:

Figure I shows a perspective view of a threshold door sill drainage unit; and Figure 2 shows an exploded view of the same unit as Figure 1.

Description of a preferred embodiment

A threshold door sill drainage unit 2 for providing a level threshold comprises an elongate block having two open ends 4 and 6, a base 8, front and back side walls 10 and 12, and a substantially horizontal upper surface 14. The unit is preferably cast from polymer concrete to give a strong, lightweight and smooth-surfaced construction. The block is hollow in order to define an interior drainage cavity 16. A slot 18 extends from end to end of the upper surface 14 to provide access to the drainage cavity 16.

In the present embodiment three spaced circular openings 20 are provided in the front wall 10. These circular openings are each provided with a removable plastics plug 2 2 which allows one or more of the openings 20 to be selectively sealed.'One of the openings 20 can also be used to connect to a drainage pipe (not shown).

Towards the back side wall 12 a metal water bar 30 is cast into the upper surface 14 of the unit 2 rearwardly of and parallel to the slot 18. The bar 30 extends along the entire 4 length of the unit. A suitable material for such a bar 30 is galvanised steel or stainless steel. When the unit is installed, the bar is cut into the door frame in order to enhance the efficiency of the unit and to prevent water passing around the ends of the bar. This has proved to be a considerable advantage over other systems that have been tried for this 5 purpose.

In an alternative embodiment (not shown) a groove filled with a polypropylene material is provided in the upper surface 14 of the unit adjacent its back side wall in order to provide a fixing strip for a proprietary door seal. This groove, like the water bar 30, extends from end to end of the unit. The polypropylene material can be cast into the unit during fabrication so that it bonds securely with the material of the unit. The polypropylene provides a better medium for securing a proprietary door seal to the unit. Such proprietary door seals may provide additional flanges or the like to enhance the draft exclusion properties of the unit.

The front part of the upper surface 14 of the unit is provided by means of a flange 32 which extends over the interior drainage cavity and provides one side of the slot 18. A three sided cutout 34 is formed in the central part of the flange 32 as best shown in Figure 2. Where the cutout 34 merges with the remainder of the flange, a rebate 36 is formed at the same level as a cutout upper surface 3 8 of the front side wall 10 in the cutout region. This provides a continuous three sided ledge 40 which supports a correspondingly rebated lower surface 42 of a removable rectangular cover plate 44formed of the same material as the rest of the unit 2.

The lower surface 42 of the removable cover plate is rebated along all four sides in order to define a central plug region 46 of greater depth than an edge region of the cover plate 44. The upper surface 48 of the cover plate 44 seats flush with the remainder of the flange 32 when the rebated lower surface rests on the ledge 40.

Bosses 50 are formed against an internal back side wall of the drainage cavity. An upper face of each of the bosses 50 is preformed with a screw locating hole S2. Tangs or tags (not shown) are formed projecting from the edge of the plug region 46 at positions which correspond to the positions of the bosses 50. Each tang is pierced in order to receive a screw and hold its head. These screws can then be used to secure the cover plate 44 to the remainder of the unit. The screw heads are accessible through the slot 18 in order to remove the cover plate 4-4 to gain access to the drainage cavity 6 for cleaning purposes.

The drainage cavity 16 is open at each end of the unit. Removable plastics plugs 60, which force fit into each end of the unit are provided. These are similar to the plastics plugs 22 used to selectively close one or more of the openings 20 in the front side wall 10.

The length of the unit is preferably, approximately, 930 millimetres to suit most new door sizes. The unit can be cut down to size on site. This is preferably done by cutting an equal amount from each end of the unit in order to retain the symmetry. The use of the plastics plugs 60 allows the ends which have been cut to be resealed. Preferably the end caps are removed again and glued to the ends of the unit when it has been cut to the correct size.

The unit replaces the traditional wooden sill and first row of bricks under the sill. Its height is selected to match the equivalent height of the traditional wooden sill and single brick course. The unit can be coloured to match existing building materials. When cast out of polymer or resin concrete the total weight of the unit can be approximately 20 kg so that it is easy to handle on site.

During installation the unit is seated beneath the door with the damp proof membrane dressed up to and butting onto the unit. When fitting a unit with an installed water bar, 6 the door frame is notched to accept the steel water bar as it extends the full length of the unit. This will ensure that no water will seep past the water bar in this area. Preferably the unit is installed with the removable cover 4-4 screwed in place.

The water collected by the unit may be dispersed either by removing a single outlet plug 22 in the front side wall of the unit and connecting a drainage pipe that runs to either a mains drain or soak away. Alternatively one or all of the outlet plugs in the front wall of the unit may be removed to allow the water to discharge into a gravel bedding layer positioned under adjacent paving. To prevent any gravel entering the unit, it is recommended that a piece of geotextile material is dressed across the outlets in the front side wall of the unit.

When the door is closed, the bottom of the door covers the slot 18. This results in an aesthetically pleasing unit which is totally unobtrusive and hidden by the door when closed.

Because the unit replaces the traditional door sill, it is also cost effective because no additional components are required.

7

Claims

Claims

I A threshold door sill drainage unit for providing a level threshold that comprises an elongate block having two ends, a base, front and back side walls, a substantially horizontal upper surface and an interior drainage cavity, a slot being defined in the said upper surface communicating with the drainage cavity, and at least one opening in the front side wall communicating with the drainage cavity, characterised in that at least part of the of the upper surface is defined by means of a flush removable cover providing access to the drainage cavity, and in that at least one of the ends opens directly into the drainage cavity and a removable end plug is provided to seal each open end of the drainage cavity.
2. A door sill drainage unit as claimed in claim 1, wherein both ends are open and are provided with respective end plugs.
3. A door sill drainage unit as claimed in claim I or 2, wherein a water bar is cast into. the upper surface of the unit adjacent its back side wall and extends from end to end so that it can be cut into a door frame when the unit is installed.
4. A door sill drainage unit as claimed in claim I or 2, wherein a groove filled with a polypropylene material is provided in the upper surface of the unit adjacent its back side wall in order to provide a fixing strip for a proprietary door seal.
5. A threshold door sill drainage unit for providing a level threshold that comprises an elongate block having two ends, a base, front and back side walls, a substantially horizontal upper surface and an interior drainage cavity, a slot being defined in the said upper surface communicating with the drainage cavity, a water bar positioned rearwardly of the slot, and at least one opening in the front side wall communicating with the drainage cavity, characterised in that the water bar 8 extends the whole width of the unit and its ends are notched into a door frame in use.

A door sill drainage unit as claimed in claim 5, wherein at least part of the of the upper surface is defined by means of a flush removable cover providing access to the drainage cavity, and in that at least one of the ends opens directly into the drainage cavity and a removable end plug is provided to seal each open end of the drainage cavity.

A door sill drainage unit substantially as herein described with reference to the accompanying drawings.