GB2580028A - Sash windows and methods of draughtproofing thereof - Google Patents

Abstract

The window 10 comprises sashes 11, 12 for sliding relative to a window frame with the sash window further comprising a parting bead 14. First memory foam seals (24, fig 3) are located within respective grooves in each side of each sash and a second memory foam seal (21, fig 3) is within a channel of the parting bead. The sash may further comprise a staff bead 15 and a third memory foam seal (23, fig 3) within a channel of said staff bead. The sash may further comprise a mid-rail 13 and a fourth memory foam seal 20 within a channel of said mid-rail. The first memory foam seal may be flipper seals while the second, third and fourth memory foam seals may be bubble seals. The window may further comprise a glass unit comprising two panes, wherein each pane has a thickness of 2 to 5mm and the panes define a cavity with a thickness of 5 to 9mm or 4 to 8mm. Also disclosed is a method of draughtproofing a sash window.

Description

SASH WINDOWS AND METHODS OF DRAUGHTPROOFING THEREOF

Technical Field

This invention generally relates to sash windows and to draughtproofing sash windows.

Backaround

Known sash windows typically have one or more movable panels, or "sashes" that form a frame to hold panes of glass, which are often separated from other panes (or "lights") by glazing bars. Each sash window may slide in a channel formed in the surrounding window frame, also known as the "case". The channels may be formed by a dividing parting "bead" which is usually parallel to the plane of the windows and extends around the inside of the frame.

The expression "sash window" refers usually to windows where the glazed panels are opened by sliding vertically or horizontally. The expression "sash window" may be used interchangeably with the expression "box sash windows", so called because weights are concealed in the box case.

The space required for the window to slide in its channel often leads to draughts being allowed to pass through the window as well as allowing the window to rattle within the case in windy conditions, therefore creating noise. Moreover, the gap itself may allow for further noise and moisture which often results in the rotting of the wood. The rot normally occurs externally often due to gloss paint sealing in moisture Any attempts of addressing the above problems and improve the efficiency of the sash window must take into account that such windows are often subject to planning io regulations and planning control for conservation areas and for listed buildings. These regulations require the original character and appearance of the building, such as Victorian or Edwardian facades, to be preserved (externally and internally). For this reason, double glazing cannot easily be achieved with current sash windows.

is Sash windows often include brush-style seals which have a number of bristles.

Insulating brushes, however, have a number of disadvantages, including absorbing moisture which leads to deterioration. They flatten and become ineffective when wet or if painted.

Other seals made of compressible foam material known as "memory foam" or "weather seals" or "compressible gasket seals" exist, but such seals can hinder a smooth and efficient sliding motion of the sashes. Such memory foam seals have been used at most in restricted areas on the sash windows. For example, patent application GB2281580A discloses the use of comprehensible foam seals attached to the sash window itself rather than its surrounding frame. Patent 3623586583 discloses draught proofing of sash windows, where a combination of brush-style seals and compressible seals is used, with the compressible seals being limited to locations between moving surfaces of the widow, specifically, the mid-rail and the bottom of the bottom sash. Such windows still suffer from the disadvantages mentioned above.

It is an aim of the present invention to address the above-mentioned problems of sliding sash windows. In particular, it is aimed to provide effective draughtproofing, including an energy efficient sash window for period buildings as well as methods for refurbishing existing windows with replacement sashes.

Summary

According to a first independent aspect of the invention there is provided a sash window comprising sashes for sliding relative to a window frame, the sash window further comprising a parting bead, first memory foam seals within respective grooves in each side of each sash, and a second memory foam seal within a channel of the parting bead.

io In other words, the first memory foam seals are provided around the perimeter of each sash. It will be appreciated that the sash window may be a refurbished or a newly constructed sash window. This combination of memory foam seals provides an efficient sealing system.

is In a dependent aspect, the sash window further comprises a glass unit comprising two panes, wherein each pane has a thickness of 2 to 5 mm the panes defining a cavity with a thickness of 5 to 9 mm, preferably 6 to 9 mm. Laminated acoustic glass panes can have thicknesses of 4 mm, 6.8 mm or 8 mm for example.

In a dependent aspect, the glass pane glass unit has an overall thickness up to 16mm.

The overall glass (double glazed unit) thickness may be and up to 18.8 mm for acoustic glass for example. In a further dependent aspect, the glass unit is provided with energy efficient glazing such that it has a U-value of 1.1 to 1.7 W/m2.

By incorporating the combination of sealing system and energy efficient glazing, the profile of the glass unit may be reduced, whilst providing thermal insulation, acoustics and draft proofing. Advantageously, the slim profile sliding sash window with an ultra slim box can be used in most situations as such windows will operate with traditional cords and weights in the traditional manner.

In a second independent aspect of the invention there is provided a method of draughtproofing or refurbishing an existing sash window, the method comprising the steps of: providing primary memory foam seals within a groove around the perimeter of each sash, and providing a secondary memory foam seal within a channel of the parting bead.

Further dependent aspects are provided in the dependent claims.

Brief description of the Figures

Aspects of the invention will be described with reference to the Figures, in which: io Figures 1A and 1B respectively show side and top views of a sash window; Figures 2A and 2B show partial detailed views of Figure 1A, including a draughtproofing system according to aspects of the invention; Figure 3 shows a partial detailed view of Figure 1B, including a draughtproofing system according to aspects of the invention; /5 Figures 4A and 4B show examples of slim glass units for use in aspects of the invention; Figures 5A to 5C shows examples of bubble seals; Figures 6A to 6D shows examples of flipper seals; and Figure 7 is a table describing characteristics of slim glass units for use in aspects of zo the invention.

Detailed description

With reference to Figures 1A and 1B, a sash window 10 extends between a window head 100 at the top and a window sill 200 at the bottom. The sash window 10 comprises an upper sash window 11 and a lower sash window 12 (wooden opening sashes) which meet at mid-rail ("meeting rail") 13. A parting bead 14 separates the upper sash window 11 from the lower sash window 12. Staff beads 15 help to keep the sash windows in place in the sash box 16.

Memory foam seals 20, 21 are respectively included across the mid-rail 13 and along parting bead 14 (within a channel of the parting bead). With reference to Figures 2A, 2B, and 3, additional memory foam seals 23 are included in the staff beads 15 and further memory seals 24 are also included In respective grooves (channels) formed in each side of each sash 11,12. In other words, the memory seals 24 are included around each sash 11, 12, substantially around the perimeter of each sash 11,12 although it would be appreciated that there may be gaps at the ends of each side, and the seals do not necessarily run along a continuous perimeter. For the avoidance of doubt, the perimeter of each sash refers to the outside of the timber that makes up the sash (typically a rectangular perimeter). Importantly, each side of the sash 11,12 has a memory foam seal 24.

An example of memory foam weather seal is made of polyurethane (PU) foam seals.

Memory foam weather seals preferably have the following characteristics/advantages over other seals: * Excellent memory -they return to original shape after compression.

* Stability -low/no stretch gained by glass fibre internal cord or insert.

is * Easily compressed -low compression forces, unaffected by temperature variance.

* Very good acoustic performance.

* Very good thermal conductivity.

* Paint and stain proof -properties unaffected by standard paints and stains.

* Stabilised -unaffected by rot, fungi, UV light or ozone.

* Wide temperature range: +70°C to -65°C.

In this example, the mid-rail seal 20, parting bead seal 21 and staff bead seal 23 are Schlegel Q-Lon® QL48650 "bubble seals". Bubble memory foam seals are also known in the art as bubble gaskets. Parting bead seal 21 runs from the top to the bottom of the parting bead 14 and is cut halfway through. Bubble seals compensate for boxes that may become mis shaped over time. The bubble seal may be cut half way through so it fits within the channel of the parting bead 21 and is not seen.

Figures 5A to 50 show examples of bubble seals as may be fitted within channels or grooves made in the timber. It may be seen that the base of the bubble seals is fitted within a track. In particular, Figure 5B shows a bubble seal fitted in a staff bead 15. The bubble seals in Figures 5B and 50 may be cut above the surface of the timber, so they fit within the timber and do not protrude outside the recess formed in the timber.

Memory foam seals 24 in this example are each a Schlegel Q-Lone AQ21 "flipper seal" which is included on each side of each sash 11,12. Flipper memory foam seals are also known in the art as flipper gaskets and they have the advantage that they only 5 open when necessary.

Figures 6A to 60 show examples of flipper seals as may be fitted within channels or grooves made in the timber. Advantageously, flipper seals 24 are included within a groove 11', 12' around the perimeter of each sash 11, 12. Advantageously, flipper io seals fold back into the groove so they do not affect the movement of the sash.

With reference to Figure 2B the staff bead 15 also includes a memory foam seal 23, which may optionally be of the same type as the seal used in the parting bead 14.

With reference to Figure 1B show a window section from the top, the box 16 is chosen to have a slim profile with a high U-value glass pane, as will be exemplified in Figures 4A and 4B. The combination of an efficient draughtproofing system of integrated memory foam seals with a slim profile is particularly advantageous as it provides an effective solution for Victorian and Edwardian facades for example.

Figure 4A shows an example of conservation approved double glazing, having an inner pane and an outer pane of 4mm each, with a krypton gas filled cavity of 6mm. In contrast, acoustic glass panes have a thickness of around 6.8 mm. This unit is referred to as a 'heritage 4/6/4 unit', having an overall thickness of 14mm and a centre pane U-value of 1.1 to 1.3 W/m2 (or 1.4 to 1.5 W/m2). The outer pane is clear whilst the inner pane is coated with glazing such as SafeGuard TM glazing. The inside of the inner pane is treated with SOFT COAT TECHNOLOGY (Guardian Climaguard Tm) by SafeGuardTm glazing.

In other embodiments, the cavity is thicker, having 8mm, as show in Figure 4B. This heritage 4/8/4' unit has an overall thickness value of 16 mm. This unit achieves a pane U-value of 1.1 to 1.3 W/m2 preferably 1.1 to 1.2 W/m2, meeting the stringent energy saving criteria set out in document L of UK building regulations (https://www.designingbuildingsto.uk/wiki/Building regulations#Part L: Conservatio n of fuel and power) . The slim profiles make the upgrade to double glazing almost undetectable from a distance, preserving the historical integrity of the windows. This is the case for both replacement sashes with integral memory foam seals and for new box sash sliding sash windows (also with integral memory foam seals). Advantageously, the slim glass units can be housed in narrow sash houses either within existing narrow boxes or within newly constructed narrow wooden boxes, making the upgrade appear almost io identical to the existing arrangement.

In some cases, particularly when the original windows have been changed to inferior windows (often with poor quality timber and aesthetically out of keeping), new bespoke windows are the only option. Advantageously, the sliding sash windows with integrated is memory foam seals and slim profiles (approved heritage glass) fit seamlessly into Victorian and Edwardian facades for example. Sash windows according to aspects of the invention are energy efficient whilst enabling a completely authentic look in line with planning regulations and conservation areas.

It will be appreciated that the draughtproofing system comprising the combination of memory foam seals may be included in new sash windows as well as in replacement sashes for existing window boxes. In the prior art, a spiral balance is normally fitted to operate sash windows when there is not space to fit a traditional box arrangement. The slim profile sliding sash window with an ultra slim box can be advantageously used in most situations. These windows will operate with traditional cords and weights in the traditional manner, e.g. cylindrical lead weights 38 to 40 mm diameter, or square lead weights.

An example method of refurbishment and comprehensive overhaul of existing sliding timber sash windows using a sealing system according to aspects of the invention (with the existing sashes being retained) is described below: * All frame joinery is comprehensively rubbed down.

* The sills are sanded/burned back to bare wood/timber.

B

* All rotten wood is cut out and restored using repair care products such as DRY FIXO/DRY FLEX® for example. Preferably, the repair product is epoxy based to enable the wood to remain elastic and thus accommodate any movement.

* Any new wood is coated with a primer.

* Existing sashes 11, 12 are removed and are sanded back to bare wood on the external face.

* Timber is made good using repair care products.

* Conservation joints are created to allow for movement in existing sashes.

* The sashes 11, 12 are planed down to facilitate smooth mechanical operation -just io a nominal margin to accommodate the memory foam seals.

and a memory foam weather seal 24 is routed into the perimeter of each sash 11, 12 and across the mid-rail.

* Sash weights are calculated and re-calibrated to accommodate the existing sash units-changes in glass over the years often result in an imbalance.

is * All sash cords are replaced with pre-stretched nylon cord.

* Parting and staff beads are removed and replaced. The new beads have integral memory foam seals.

* New high-quality window accessories are supplied, such as brass/chrome pulley wheels, sash lifts and a lockable heritage fitch fastener (secured by design).

The example protocol for refurbishment as described above works effectively to reduce air, noise and dust ingress and completely preserves the historical integrity of the windows.

The DRY FIX®/DRY FLEX® primer and repair system is a durable solution for decayed and damaged joinery. DRY FIX® primers penetrate deep into the fibres of the wood ensuring that DRY FLEX® bonds permanently. Based on a unique epoxy resin formula, DRY FLEX® remains elastic so that it accommodates any movement. The repair system may be used when joining timber together primarily to act as a waterproof expansion joint. This includes the work to the sills and lower portions of boxes with sash windows or the frames of casement windows. Use of the repair system in combination with traditional joinery methods ensures that the box, frames, existing sashes including conservation joints and sills are in good order before any draught proofing to existing sashes or new replacement sashes are fitted.

An example method for replacing sashes incorporating the sealing system according to aspects of the invention is described below: * Existing sashes and glass are removed and disposed of (unless useful).

* All frame joinery is comprehensively rubbed down.

* The sills are sanded/burned back to bare wood.

* All rotten wood is cut out and restored using repair care products such as DRY FIXO/DRY FLEX® for example. Any new wood will be coated with primer.

/o * Sets of high-quality hardwood sashes 11, 12 are supplied and fit, pre glazed with conservation approved double glazed units (toughened where needed) as standard. A memory foam weather seal 24 is routed into the perimeter of each sash 11,12 and across the mid-rail.

* Sash weights are calculated and re-calibrated to accommodate the new sash /5 units fit is anticipated that existing weights will be replaced with bespoke lead weights).

* All sash cords to be replaced with pre-stretched nylon cord.

* Parting and staff beads are removed. They are replaced with new beads incorporating a memory foam seal.

zo * New high-quality window accessories are supplied, such as brass/chrome pulley wheels, sash lifts and two lockable heritage fitch fasteners. Two fitches pull the mid-rail together and maximise the benefit of the mid-seal. Two fitches may be used in all systems.

An example method of refurbishment and comprehensive overhaul of existing casement windows using a sealing system according to aspects of the invention is described below: * All frame joinery is comprehensively rubbed down.

* The sills are sanded/burned back to bare wood/timber.

* All rotten wood is cut out and restored using repair care products such as DRY FIXED/DRY FLEX® for example.

* Any new wood is coated with a primer.

* Timber is made good using repair care products for example.

* Conservation joints are created to allow for movement in existing sashes.

* The sashes 11, 12 are planed down to facilitate smooth mechanical operation and a memory foam weather seal 24 is routed into the perimeter of each opening sash.

* New window furniture is fitted to the opening sashes, including hinges, fasteners and stays.

A method of replacing bespoke sashes for existing casement windows includes similar preparatory steps to those listed in the method above. New double glazed sashes are provided, protected with a primer/undercoat. The sashes 11, 12 are planed down to io facilitate smooth mechanical operation and a memory foam seal 24 is routed into the perimeter of each opening sash 11, 12.

An example method of replacing sliding sash windows incorporating a sealing system according to aspects of the invention is described below: * Sets of sliding sash hardwood sashes are supplied and fit, pre glazed with conservation approved double glazed units (toughened where needed) as standard. A memory foam weather seal 24 will routed into the perimeter of each sash 11, 12 and across the mid-rail.

* The sashes 11, 12 are balanced with narrow cylindrical lead weights, e.g. having 38 to 40 mm diameter.

* Sash cords are replaced with pre-stretched nylon cord.

* Parting and staff beads incorporate a memory foam seal.

* New window accessories are fitted to include sating chrome pulley wheels, sash lifts and fitch fasteners.

Claims (18)

11 Claims 1 A sash window comprising sashes for sliding relative to a window frame, the sash window further comprising a parting bead, first memory foam seals within respective grooves in each side of each sash, and a second memory foam seal within a channel of the parting bead.

2. A sash window according to claim 2, wherein the first memory foam seals are flipper seals and wherein the second memory seal is a bubble seal.

3. A sash window according to claim 1 or claim 2, further comprising a staff bead and a third memory foam seal within a channel of the staff bead.

4. A sash window according to claim 3, wherein the third memory foam seal is a is bubble seal.

5. A sash window according to any one of the preceding claims, further comprising a mid-rail and a fourth memory foam seal within a channel of the mid-rail.

6. A sash window according to claim 5, wherein the fourth memory foam seal is a bubble seal.

7. A sash window according to any one of the preceding claims, further comprising a glass unit comprising two panes, wherein each pane has a thickness of 2 to 5 mm, the panes defining a cavity with a thickness of 5 to 9 mm, or 4 to 8mm.

8. A sash window according to claim 7, wherein the cavity has a thickness of 6 to 8 mm.

9. A sash window according to claim 8, wherein the glass unit has an overall thickness of at most 16mm and up to 18.8 mm for acoustic glass

10.A sash window according to claim 9, having a U-value of 1.1 to 1.7 W/m2.

11.A sash window according to claims 7 to 10, wherein the cavity is filled with krypton gas.

12.A sash window according to any one of the preceding claims, wherein said seals comprise polyurethane.

13.A method of draughtproofing a sash window comprising sashes for sliding relative to a window frame and a parting bead, the method comprising the steps of: providing first memory foam seals within respective grooves in each io side of each sash, and providing a second memory foam seal within a channel of the parting bead.

14.A method according to claim 13, further comprising the step of providing a glass unit comprising two panes, wherein each pane has a thickness of 2 to 5 is mm, the panes defining a cavity with a thickness of 5 to 9 mm.

15.A method according to claim 11, wherein the cavity has a thickness of 6 to 8

16.A method according to claim 12, wherein the glass unit has an overall thickness of at most 16mm.

17.A method according to claim 13, further comprising glazing at least one pane of the glass unit such that the unit has a U-value of 1.1 to 1.7 W/m2.

18.A method according to claim 17, wherein the unit has a U value of 1.5 W/ m2.