GB2444181A

GB2444181A - Air tight system for building with vapour impermeable sealing strips

Info

Publication number: GB2444181A
Application number: GB0723252A
Authority: GB
Inventors: Michael James Mapston
Original assignee: A Proctor Group Ltd
Current assignee: A Proctor Group Ltd
Priority date: 2006-11-27
Filing date: 2007-11-28
Publication date: 2008-05-28
Also published as: GB0623692D0; GB0723252D0

Abstract

A building construction comprising a framework 9 of spaced apart frame members 10, 12 which support, on one side, a vapour control layer 30 of a substantially water vapour impermeable material. The vapour control layer is attached to the framework by sealing strips 1. The sealing strips comprise portions of a substantially water vapour impermeable sheet material which is bonded in use to the frame members of the framework. The sealing strip has a layer of a pressure sensitive adhesive on one side which bonds to the vapour control layer. The sealing strips may be fixed along all edges of frame members by means of fixings or adhesive and the vapour control layer may be a polythene sheet. The sealing strip may comprise a layer of release paper. The sealing strip may be a water impermeable plastics material which may preferably comprise a reflective foil backed by a corrugated board. The sealing strip may be supplied in the form of a roll and may be provided with pressure sensitive adhesive on both sides. The sealing strip may be folded about a predetermined fold line to enable installation. The sealing strip, per se, is also claimed.

Description

AIR TIGHT SYSTEM

The present invention relates to timber frame or light gauge metal frame building constructions that require the installation of a vapour control layer (VCL) Timber frame construction is an increasingly popular method of building. It offers the advantages of a relatively lightweight construction that can be built quickly, with prefabricated framework sections being delivered to a site for installation and finishing.

For example, a typical wall construction comprises a framework of spaced apart vertical frame members (studs') and horizontal frame members (rails) . The outer surface of the framework is covered by panelling and the spaces between the studs may be filled with a suitable thermal insulation material. The inner surface of the framework is covered with a layer of water vapour impervious material, a vapour control layer' (VCL) before attachment of an inner plasterboard wall surface. The wall is then generally completed by providing an outermost layer of weatherproof material such as brick.

The purpose of the vapour control layer, typically a polyethylene sheet, is to prevent warm humid air from the inside of the building passing into the relatively cooler spaces between the studs or thermal insulation placed therein, where moisture would condense resulting in dampness and damage to the structure or the insulation. In hot climates where the air outside a building may be warmer and more humid than on the inside then the VCL is fitted on the outside of the framework rather than on its inner surface, to prevent the warm moist air from the outside penetrating into the framework spaces or insulation and condensing, i.e. a VCL is installed on the warm side of a framework in each case.

Any gaps or defects in the seal between the vapour control layer and the framework can allow moisture to bypass the vapour control layer resulting in undesirable condensation.

Furthermore there is a move to make rooms "airtight" and to provide ventilation only through windows, doors or other specific ventilation systems.

Similarly a typical floor and/or ceiling construction may comprise a framework of spaced apart frame members ("joists") laid out between walls of a building. To form a floor, flooring panels or boards may be attached to the upper surface of the framework (i.e. on top of the joists) and to form a ceiling plasterboard can be attached to the underside of the framework. Thermal and/or acoustic insulation is often provided between the spaced apart joists. As with a wall construction a vapour control layer (VCL) may be desirable to prevent damage caused by condensation. For example a VCL may be required for the ceilings of relatively warm and humid rooms such as kitchens and bathrooms to prevent condensation occurring above them. Similarly a ceiling including a VCL may be desirable in the upper rooms of a building where the ceilings are adjacent a relatively cool roof space. In such cases the VCL is attached to the underside of the framework of joists before installation of the ceiling plasterboard panels. Where a VCL is required to prevent moisture passing through a floor it is installed on the upper side of the framework of joists.

In some cases timber frame constructions such as a wall construction are supplied with a VCL that has already been fitted in the factory but such arrangements can be damaged in transit or upon construction. More often open cell' timber frameworks are provided, where thermal insulation and a VCL are installed on site, after erection of the timber frame. Installing vapour control layer material across a timber (or metal) framework and attaching it by taping or stapling to the framework can be time consuming and achieving an airtight' i.e. moisture vapour tight, seal at all of the edges of the wall framework can be difficult. For example the polyethylene or other thin sheeting material can be easily torn whilst being spread across a framework, especially when using fixings such as staples on such materials, in on-site conditions. This can result in poor quality sealing, especially at edges leading to condensation problems. In addition where vapour control layers are being installed on frameworks that adjoin at right angles, such as two walls forming the corner of a room, it is difficult to reach into the corner to securely and reliably fix the edges of the VCLs to the edge of each wall framework and so gaps may be left. Furthermore, it is desirable that any method employed to fit a vapour control layer should be both simple and rapid, requiring a low input of labour, as labour costs are rising relative to the cost of materials.

It is an object of the present invention to avoid or minimize at least some of the aforementioned disadvantages.

Accordingly the present invention provides a building construction comprising a framework of spaced apart frame members, wherein said framework supports on one side a vapour control layer of a substantially water vapour impermeable material, said vapour control layer being attached to said framework by sealing strips, said sealing strips comprising portions of a substantially water vapour impermeable sheet material bonded in use to frame members of the framework, and having a layer of a pressure sensitive adhesive on the side facing away from the framework which bonds to the vapour control layer.

The frame members may be, for example, the studs and rails of a timber frame wall or the joists of a floor or ceiling.

The sealing strips provide a rapid and effective means of attaching the vapour control layer to the appropriate surface (inner or outer) of a framework during the construction of a building.

!5 After constructing the framework and installing any required insulation between the studs in the convential manner the sealing strips are bonded to the framework.

Preferably the sealing strips are of a semi-rigid sheet material, for example a suitable plastics material.

Sheets of such materials have sufficient stiffness so as to be easy to position on a vertical surface such as a timber stud whilst at the same time being sufficiently pliable to conform to deviations or imperfections of the surface which they are bonded to. The desired degree of rigidity of the sealing strips can be achieved by making the sheets of an appropriate thickness or by forming the material into sheets having a rigid structure, for example the sheets may have a "corrugated" core to enhance rigidity, with smooth outer covering layers. A preferred sealing strip sheet material comprises an air and water vapour impervious reflective foil, backed by a corrugated board sheet.

Bonding to the frame members (e.g. studs, rails or joists) of the framework can be achieved by means of fixings such as staples for example. Alternatively adhesive can be used. Once the sealing strips are bonded to the framework the layer of pressure sensitive adhesive, which is generally covered by a release paper prior to use, is used to attach the vapour control layer. Preferably the vapour control layer is a sheet material such as, for example, a polyethylene sheet material. The vapour control layer is generally supplied as a roll which can easily be installed by unrolling across the framework, attaching immediately by means of the adhesive layer on the already installed sealing strips. The vapour control layer material is then trimmed to fit. Hand pressure or a roller may be used to ensure good adhesive contact between the sealing strips and the vapour control layer. After installation of the vapour control layer wall, floor or ceiling can be completed by the attachment of further layers such as plasterboard, floor board or an outer brick layer as appropriate.

Preferably all of the boundary edges of a framework and the edges of any apertures in the framework, facing the vapour control layer, are provided with sealing strips running continuously along the edges.

Providing sealing strips that run continuously along all edges of a framework for example around window, door or ventilation apertures and at the joins between the walls, ceilings, floors and other walls gives a substantially airtight seal to that framework. This prevents water vapour leaking past the edges of the vapour control layer.

Preferably the building construction comprises sealing strips which are folded along their length to conform, in use, about edges of apertures in the building construction or about corner, floor and ceiling edges where a framework adjoins adjacent wall, ceiling or floor frameworks. For example, where two walls meet to form the corner of a room, a sealing strip or strips is, folded along a pre-determined fold line, generally down the centre of the strip. The sealing strip is then bonded to the framework of each wall at the edges where they meet. The fold line runs down the line of the corner. The portion of the sealing strip to one side of the fold is bonded to the framework of the first wall and the portion on the other side of the fold is bonded to the framework of the second wall. At the corner the vapour control layer for each framework is easily attached, at either side of the fold in the sealing strip, as the pressure sensitive adhesive layer provides immediate adhesion. Furthermore even if the edges of the two pieces of vapour control layer sheet do not meet to provide complete coverage round the corner, the sealing strip, (which is itself water vapour impervious) folds round the corner and so bridges and seals any gap between the VCL sheets. A similar effect is obtained at junctions between wall and ceiling or wall and floor frameworks, where folded sealing strips ensure continuity of the water vapour impervious layer.

Other benefits are obtained where the sealing strips are folded round the edge of an aperture, for example a window aperture in a wall framework. The vapour control layer wraps round the edges of the studs and rails which form the aperture to form a particularly strong attachment and secure seal.

Sealing strips for use in a building construction of the invention, as described above, constitute a further aspect of the invention. Thus according to a second aspect the present invention provides a sealing strip, for use in attaching a vapour control layer to a framework building construction, comprising a sheet of a substantially water vapour impermeable material having a layer of a pressure sensitive adhesive on one side for bonding, in use, to a said vapour control layer.

Preferably the sealing strip further comprises a layer of a release paper, releasably attached to the pressure sensitive adhesive layer. This protects the adhesive layer before use.

The sealing strip may be made of any water vapour impermeable material that is sufficiently robust and durable. For example it may be made of a plastic sheet material. A preferred sealing strip sheet material comprises an air and water vapour impervious reflective foil, backed by a corrugated board sheet.

Preferably the sealing strips are of a semi-rigid sheet material, i.e. the strips are sufficiently stiff to hold their shape when being installed but also will bend readily to conform to deviations and imperfections of frame members such as studs rails or joists to which they are bonded.

Preferably the sealing strip is provided in the form of elongate lengths on a roll. Long lengths of sealing strip can be readily unwound from such roll during installation.

Alternatively shorter lengths of sealing strip may be provided which can be attached to a framework in end-to-end fashion or with their ends overlapping slightly. Sheets of sealing strip material can be of any size and cut to fit but advantageously the sealing strip is provided in elongate lengths having a width corresponding to the width of framework members (studs, rails or joists) to which it is to be bonded.

Ereferably the sealing strip is foldable along its length.

This allows the sealing strip, to be folded to conform around corners and edges as previously described. More preferably the sealing strip folds about a pre-determined fold line. This can be achieved, for example, by providing a sealing strip that is pre-creased or scored along the desired fold line.

Most preferably the sealing strip is foldable and is provided in elongate lengths with a width corresponding to or less than twice that of framework members to which it is to be bonded in use. This has the advantage that the strip can be folded, in use, about edges or corners as required, but can also be cut along the fold line, to provide sealing strips of an appropriate width for use on frame members where no folding is required.

The pressure sensitive adhesive layer on the sealing strips may be of any adhesive having a suitable strength and durability.

The pressure sensitive adhesive layer may cover all of the side of the sealing strip which bonds to the vapour control layer in use. However effective bonding and sealing can be achieved by providing a layer of adhesive that does not cover all of one side of the sealing strip. For example, where the sealing strip is foldable and provided in elongate lengths, as described, above the adhesive layer may comprise two separated strips of a pressure sensitive adhesive, one to each side of the fold line and running generally parallel along the entire length of the sealing strip.

As previously described the sealing strips of the invention may be bonded in use to a framework by fixing means such as staples. However other means of bonding the sealing strip to the frame members can be used. Advantageously the sealing strip is provided with a layer of pressure sensitive adhesive on both sides. In use the adhesive layer on one side is used to bond the strip to the framework and that on the other side to bond to the vapour control layer. The use of such double sided' sealing strips, with an adhesive layer on both sides is preferred in some applications. For example, where the framework is of metal rather than wood, precluding the use of conventional staples. Furthermore double-sided sealing strips are quickly and easily installed and provide a good seal to both the vapour control layer and the frame members.

According to a third aspect the present invention provides a method for constructing a building comprising the steps of: forming a framework of spaced apart frame members; bonding sealing strips to said framework, said sealing strips comprising portions of a substantially water vapour impermeable sheet material having a layer of a pressure sensitive adhesive on the side facing away from the framework; and attaching a layer of a substantially water vapour impermeable sheet material across said framework by bonding to the said pressure sensitive adhesive layer of the sealing strips.

Further preferred features and advantages of the present invention will appear from the following detailed description of some embodiments illustrated with reference to the accompanying drawings in which: Figures 1 (a to d) show a sealing strip of the invention; Figure 2 shows, in perspective view, the installation of the sealing strips of figure 1 on a building construction; and Figures 3 (a to f) show the installation of sealing strips and a vapour control layer in the assembly of a building construction.

Figure la shows a portion of a sealing strip 1 of the invention which is an elongate sheet 2 comprising a reflective foil backed by a corrugated board material. The sealing strip 2 is pre-creased along a centre line 4 and has a layer of pressure sensitive adhesive 6 denoted by hatching on one face. The pressure sensitive adhesive layer 6 is discontinuous in this example with no adhesive adjacent the centre line 4. The adhesive layer 6 is covered before use of the sealing strip 1 with a release paper (not shown) . The sealing strip 1 can be supplied in a roll or in pre-cut lengths as required.

In use the sealing strip 1 can be cut along the centre line 4 to provide sealing strip portions 7 as shown in figure lb. After bonding to the framework of a wall as described later, in respect of figure 3, or to a ceiling or floor framework, the adhesive layer 6 can then be used to bond to a vapour control layer.

Figures ic and id show the sealing strip 1 of figure la after folding, at right angles along the centre line 4. In figure ic the sealing strip 1 is folded at right angles with the adhesive layer 6 facing inwards. In this conformation the strip can be attached (bonded) to a corner of frameworks of a building construction of the invention such as a wall framework (see figure 2) . A vapour control layer can then be bonded to the adhesive layer 6 at both portions of the sealing strip, on either side of the fold 4. In figure id the sealing strip 1 is folded at right angles with the adhesive layer 6 facing outwards. In this conformation the strip 1 can be attached around an edge of a stud or rail (see figure 2), for subsequent bonding to a vapour control layer.

The bonding of the sealing strips 1 of figure 1 (b to d) to a framework is illustrated in figure 2. Figure 2 shows in perspective a timber framework 8 built as part of a building construction 9 of the invention. The framework 8 consists of vertical studs 10 and horizontal rails 12. A second framework 8' of the building construction 9abuts the first framework 8 at right angles to form the corner 12 of a room.

Sealing strips 1 of the form shown in figure 1 are stapled to studs 10 and rails 12, and are indicated by hatching in the drawing. A sealing strip 14 folded as shown in figure lc is stapled into the corner 12 attaching to a stud 10 of each framework 8,8'. A sealing strip 16, folded as shown in figure id, is bonded to a rail 12 forming the lower edge of an aperture 18 for a window. A cut section of sealing strip 20 (as shown in figure ib) is shown stapled to a stud 10.

In use the sealing strips 14, 16, 18 are used to bond a vapour control layer to the frameworks 8,8' of the building construction 9, as illustrated in figure 3.

Figure 3a shows in elevation a typical timber framework 8 for a building construction 9, as viewed from the interior of a room. The framework 8 is constructed from vertical studs 10 spaced at 600 mm intervals and horizontal rails 12. The framework has an aperture 18 for a window and an aperture 22 for a door.

Outer wall panels 24 are attached to the framework 8 on the opposite side from that viewed except at the window and door apertures 18,22.

Figure 3b shows the building construction 9 of figure 3a with a layer of a glass fibre insulating material 26 fitted between the cells' formed by the studs and rails 10, 12 and the outer wall panels 24 (see figure 3a) Figure 3c shows the building construction during the installation of a vapour control layer. Sealing strips 1 have been bonded, by stapling to the studs 10 and rails 12 of the framework 8 in the same manner as shown in figure 2.

The sealing strips 1 have had their release paper removed to expose the pressure sensitive adhesive layer 4 (figure 1) . A 1200 mm wide roll of polyethylene sheet material 28 as vapour control layer 30 is shown being installed across the framework 9. Pressing the vapour control layer 30 to the sealing strips forms an immediate bond.

In figure 3d the installation of the vapour control layer is shown completed.

A second sheet of polyethylene sheet material 28' has been unrolled and bonded to the framework 8 in the same number as the first, so that all of the framework is covered by the vapour control layer 30, except at the window and door apertures 18, 20 where the sheet has been cut to reopen the apertures. A strip of sealing tape 32 has been applied to seal the join between the two sheets of polyethylene material 28.

When cutting the sheet material 28 at the door and window apertures 18, 20 a border 33 of the sheet material 28 is left for bonding around the edges 34 of the apertures as shown in the detail of figure 3e.

In figure 3e the vapour control layer 30 is bonded round an edge 34 of a rail 12 which has a folded sealing strip 1 bonded to it. The pressure sensitive adhesive layer 4 on either side of the fold 4 of the sealing strip 1 which runs along the edge 34 bonds the vapour control layer on both vertical and horizontal surfaces of the rail 12. This technique ensures strong, substantially airtight bonding of the vapour control layer 30 to the framework preventing ingress of condensation into the insulation layer 26 provided between the studs 10 of the wall.

Eigure 3f shows schematically in detail the situation at the corner of the room 12 shown in the building construction of figure 2. The sealing strip 14 folded round the corner 12 has vapour control layers 30, 30' bonded to the portions of the adhesive layer 6 at either side of the fold 4. The edges 36,36' of the vapour control layers 30,30' do not meet, but the sealing strip 14 provides continuity of the water vapour resistant barrier around the corner 12. Thus folded sealing strips of the invention can ensure air and water vapour tight sealing at the junction between wall frameworks as shown in figure 3f or between wall and ceiling or floor frameworks.

Claims

1. A building construction comprising a framework of spaced apart frame members, wherein said framework supports on one side a vapour control layer of a substantially water vapour impermeable material, said vapour control layer being attached to said framework by sealing strips, said sealing strips comprising portions of a substantially water vapour impermeable sheet material bonded in use to frame members of the framework, and having a layer of a pressure sensitive adhesive on the side facing away from the framework which bonds to the vapour control layer.

2. A building construction as claimed in Claim 1 wherein the frame members include the studs and rails of a timber frame wall or the joists of a floor or ceiling.

3. A building construction as claimed in Claim 1 or Claim 2 wherein the sealing strips are fixed to the frame members by means of fixings or by an adhesive.

4. A building construction as claimed in any one of Claims 1 to 3 wherein the vapour control layer is a polyethylene sheet material.

5. A building construction as claimed in any one of Claims 1 to 4 wherein the boundary edges of the framework and the edges of any apertures in the framework, facing the vapour control layer, are provided with sealing strips running continuously along the edges.

6. A sealing strip for use in attaching a vapour control layer to a framework building construction, comprising a sheet of a substantially water vapour impermeable material having a layer of a pressure sensitive adhesive on one side for bonding, in use, to a said vapour control layer.

7. A sealing strip as claimed in Claim 6 which further comprises a layer of a release paper, releasably attached to the pressure sensitive adhesive layer.

8. A sealing strip as claimed in Claim 6 or 7 made of a water vapour impermeable plastics material.

9. A sealing strip as claimed in any one of Claims 6 to 8 wherein the sealing strip sheet material comprises an air and water vapour impervious reflective foil, backed by a corrugated board sheet.

10. A sealing strip as claimed in any one of Claims 6 to 9 which are of a semi-rigid sheet material which are sufficiently stiff to hold their shape when being installed but also will bend readily to conform to deviations and imperfections of frame members such as studs rails or joists to which they are bonded.

11. A sealing strip as claimed in any one of Claims 6 to wherein the sealing strip is provided in the form of elongate lengths on a roll.

12. A sealing strip as claimed in any one of Claims 6 to 11 which folds about a pre-determined fold line.

13. A sealing strip as claimed in any one of Claims 6 to 12 provided with a layer of pressure sensitive adhesive on both sides.

14. A method for constructing a building comprising the steps of: forming a framework of spaced apart frame members; bonding sealing strips to said framework, said sealing strips comprising portions of a substantially water vapour impermeable sheet material having a layer of a pressure sensitive adhesive on the side facing away from the framework; and attaching a layer of a substantially water vapour impermeable sheet material across said framework by bonding to the said pressure sensitive adhesive layer of the sealing strips.

15. A building construction comprising a sealing strip and a vapour control layer substantially as described hereinbefore and with reference to Figures 3a to f of the accompanying drawings.

16. A sealing strip substantially as described hereinbefore and with reference to Figures la to d of the accompanying drawings.