Amembrane for weatherproofing or sealing applications having fire retardant properties

Abstract

A membrane for use as an interface sealing material in building and construction applications, the membrane comprising a layered sheet material, wherein the layers comprise at least a layer of glass-fibre sheet, a layer of silicone, and a metal foil layer. Additional layers of silicone, glass-fibre or foil may be used, and the layers may be arranged in any convenient order. Membranes according to at least some embodiments of the invention may have good water resistant properties and also have relatively low calorific value, so enabling them to meet many countries' fire classification regulations.

Description

[0001] AMEMBRANE FOR WEATHERPROOFING OR SEALING APPLICATIONS HAVING FIRE RETARDANT PROPERTIES

[0002] The present invention relates to coverings, membranes and sheet materials as are used in building and construction applications. More particularly, it relates to such products used in weatherproofing or sealing applications, and which may have fire classified, fire-resistant, or fire retardant properties.

[0003] When buildings are being built - particularly, but not exclusively commercial & residential buildings where the internal skin of the external wall is constructed before a fagade layer - it is commonplace to provide some sort of weatherproof barrier material around interfaces such as windows, doors and curtain walling, that is typically sealed against masonry, weatherboarding or woodwork behind the fagade layer. The material is generally a flexible sheet material, which can conveniently be stored on a roll, and easily manipulated. Sometimes multiple sheets may be used, where the sheets may have different purposes. For example, one sheet material may be a waterproof sheet, while another may have fire resistance properties. Other sheets may have damp-proof or useful thermal properties, and combinations of these sheets may be used to achieve a desired

[0004] At present the most common material for use as a waterproof membrane is known as EPDM (ethylene propylene diene monomer) rubber. This material provides good waterproofing properties.

[0005] There has been increased interest in ensuring that buildings are built or adapted to be as resistant to the spread of fire as is practically possible and achievable, and hence there is increasing interest in the fireproof qualities of membranes used in a building structure. EPDM is not a fire classified material, and so will easily combust and spread fire across and up buildings.

[0006] According to a first aspect of the present invention there is provided a membrane for use as an interface sealing material in building and construction applications, the membrane comprising a layered sheet material, wherein the layers comprise at least a layer of glassfibre sheet, a layer of silicone, and a metal foil layer, and wherein the percentage of silicone in the membrane is no more than 35% by weight.

[0007] Embodiments of the invention are suitable for application to buildings, using adhesives, during construction of a building, or when carrying out repair, remediation or alterations thereto.

[0008] Embodiments of the invention provide a sheet sealing product that has both water resistance properties and fire resistance properties. Some embodiments may be “fire- classified”, meaning that they are able to meet various industry-standard performance targets for prevention or reduction of spreading of fire. The performance of the product in relation to these properties is dependent upon the specific weights of each of the layers that make up the product, and so there is flexibility in tailoring the product to a specific requirement by suitable choice of these specific densities / weights. Embodiments may be non-breathable, in that they allow no, or no appreciable passage of air through the membrane. They are thus suitable for use where non-breathable membranes are used, such as in waterproof, or water-resistant applications or the like. The foil layer has been found to have particularly good waterproof abilities, over and above that provided by the silicone layer. Thus, it makes it easier to produce a membrane having a require water resistance while still also providing good fire resistance, and also being relative lightweight.

[0009] Embodiments have particular utility when used to seal interfaces in a building, such as where there are joints between elements of a structure. This may be for example where a window meets a wall, or where a cement board meets a steel frame. In general, it is particularly useful for interfaces between any practical combination of concrete structures or panelling, door or window surrounds, curtain walling, steel frame system (SFS) construction, weather boarding, secondary parapet walling, and other elements.

[0010] Embodiments are also particularly suited for where such interfaces have a horizontal component, where moisture may tend to gather, such as a flat horizontal surface. The highly waterproof nature of at least some embodiments prevent any ingress of moisture through to the structure behind the membrane, when properly applied thereto.

[0011] Typically, embodiments will be used as a secondary seal in buildings. A primary seal provides a first line of defence against weather, such as rain, fog, excess humidity etc. which might otherwise lead to an ingress of moisture. The primary seal may often be a silicone bead between external panes or frame etc. Embodiments of the present invention are generally used in a layer behind such primary seals, thus acting as a secondary seal, and may provide a last line of defence to prevent any ingress that passes the primary seal from coming into contact with the structure beneath. Of course, embodiments may also be used in different applications, where it may be a primary seal.

[0012] In some preferred embodiments of the invention the silicone layer is attached to a first side of the glass-fibre sheet, and the metal foil layer is attached to a second side of the glassfibre sheet. Thus the material comprises of a glass-fibre sheet sandwiched between a silicone and a metal foil layer.

[0013] In some embodiments the metal foil layer is attached to the glass-fibre layer using an adhesive. The adhesive maybe any suitable adhesive. It may comprise, for example, a silicone or acrylic adhesive. If the adhesive is a silicone adhesive then advantageously it may comprise a silicone composition that is the same as, or similar to, that used for the silicone layer. It may typically be a thinner layer than that used for the silicone layer. The silicone adhesive may be a water based silicone, or may be an oxime based silicone, or may be any other suitable type.

[0014] Note that the ordering of the layers is not limited to that described above. Consequently, in some embodiments the silicone layer is sandwiched between the metal foil layer and the glass-fibre layer. Thus, in such embodiments, the silicone layer may also act simultaneously as the adhesive layer for the metal foil and glass-fibre. Other embodiments may have the foil layer sandwiched between the silicone layer and the glass-fibre layer

[0015] In other embodiments the foil layer may be sandwiched between the glass-fibre layer and the silicone layer. In such embodiments an adhesive may be used to attach the foil layer to the glass-fibre layer, as described above.

[0016] Note also that some embodiments may have additional layers. For example, in those embodiments where, for a three-layer product there is either a foil layer or a glass-fibre layer on the outside, a further layer of silicone may be applied to the foil or glass-fibre layers to make a four or five layered product having multiple silicone layers, with the silicone layers as external surfaces.

[0017] Additionally, some embodiments may have multiple foil and / or glass-fibre layers. These may applied in any desired layering order. A silicone or other adhesive may be used to secure the layers together. In some embodiments the glass-fibre layer may be chosen to have a thickness of between 0.1mm and 1mm. The different thicknesses may be chosen according to strength or flexibility requirements for a given embodiment. The glass-fibre layer may advantageously comprise a woven material.

[0018] In some embodiments the amount of glass-fibre in the product may be determined by a specific weight. Some embodiments of the invention may therefore have a specific weight of between 100 and 1000 g / m2.

[0019] Advantageously, in some embodiments the specific weight of the glass-fibre is chosen to be between 400g / m2and 450g / m2. In some embodiments it may be approximately 430g / m2.

[0020] In some embodiments the silicone has a specific weight of between approximately 20g and 200g per m2. Some such embodiments may have a specific weight of silicone of approximately 80g / m2.

[0021] Note that all embodiments have a ratio of silicone to total weight (i.e., a percentage content by weight) of not more than approximately 35%. More preferably, the silicone content is kept below 25%. In some embodiments, the silicone content may be approximately 14% by weight. It will be appreciated that the ratio of silicone can affect the fire classification of a membrane, and so keeping the silicone content relatively low helps to reduce the calorific value of the membrane, and so is more likely to meet a given classification. The ratio of silicone to the other materials in the embodiment (e.g. fibreglass plus the metal foil), or the maximum desired specific weight of silicone used in the embodiment, may be found by trial and error to meet a given performance requirement.

[0022] It should also be understood that different types of silicone can have different specific calorific values. Therefore, higher percentage quantities of silicone having a lower specific calorific value may be used in a membrane and still achieve similar results as that of a silicone in smaller quantities but having a higher specific calorific value.

[0023] The silicone layer provides a degree of ultraviolet (UV) protection, and so advantageously, in use, preferably an outer layer of silicone is used for any faces that may be subject to sunlight, or some other UV source. Advantageously, in some embodiments the metal foil may be an aluminium foil. This is a relatively low cost foil with mechanical and thermal properties that are useful in a sheet material for use in building and construction work. The foil may have, in some embodiments, a specific weight of between 10g / m2and 80g / m2. Some embodiments may have a specific weight of approximately 20g / m2. It has been found that the addition of a foil layer gives improved performance in particular with regard to water resistance, and is also useful in reducing radiated heat loss from a building.

[0024] Embodiments of the present invention have been made and tested, and have been found to meet performance requirements for fire classification as determined by testing to A2-s1, dO, according to British Standard BS EN 13501-1.

[0025] The same embodiments have been found to have a resistance to water penetration of 2kPa for 24 hours according to EN 1928 under harmonised standard EN 13984, clause 5.5.

[0026] Some embodiments may be formed so as to have a surface finish on at least one surface thereof, comprising of pits, bumps, ridges, and / or dimples. This helps to add additional grip for materials sitting on or located against the product when in use, or to act as a keying surface when gluing the material to another surface. Other embodiments may have no deliberate surface finish applied, but may have a surface finish that is determined by the materials that form the various layers. For example, the fibrous or woven nature of the glass-fibre layer may be visible, either through the glass-fibre forming an outer layer, or through the texture thereof being imparted to layers attached thereto.

[0027] Advantageously, some embodiments use a high-temperature vulcanising silicone. This is cured in a curing oven after application to the glass-fibre sheet. Alternatively, a room temperature vulcanising silicone can be used.

[0028] According to a second aspect of the present invention there is provided a method of making a membrane for use in the construction industry, comprising the steps of: a) producing a glass-fibre sheet; b) applying a silicone coating across a surface of the glass-fibre sheet; c) applying a metal foil either to the glass-fibre sheet with an adhesive or to the silicone coating. The membrane so produced may be a membrane as describe in relation to the first aspect of the invention, and so optionally have the various features and elements as described above. Note that the method may apply one layer to another in any preferred order.

[0029] According to a third aspect of the present invention there is provided a method for weathersealing a part of a building from water ingress, comprising the steps of: a) taking a membrane as claimed in any of the appended claims; b) trimming as required the membrane so as to fit around a joint, feature or other element to be sealed; c) applying an adhesive to the joint, feature or other element to be sealed, the adhesive being trowelled to be relatively uniform and flat and to cover a region similar or slightly larger in size to the trimmed membrane; d) applying the membrane to the adhesive, and using a roller or press to push the membrane into the adhesive; e) applying a further quantity of adhesive over the border of the membrane and trowelling the bead to be a flat thin surface over the border;, to provide a weather-proof covering over the joint, feature or other element.

[0030] Embodiments may typically be applied in strip form, to seal linear joints. Thus, the membrane may be cut (or bought appropriately sized) to provide a membrane border around a joint of between 50mm and 200mm or thereabouts. This allows sufficient adhesive to sit under the membrane to give good water sealing properties. Of course, borders outside of this range will also have efficacy.

[0031] Embodiments of the invention will now be described in more detail, by way of example only, and with reference to the following Figures, of which:

[0032] Figure 1 diagrammatically illustrates a cross section of an embodiment of the invention;

[0033] Figure 2 diagrammatically illustrates a typical situation where embodiments of the invention may be used, namely in this instance to provide an interface seal between a window frame and a sheathing board; and

[0034] Figure 3 diagrammatically illustrates various stages of the application of an embodiment of the invention to a window frame, with Figure 3a showing an initial application of adhesive, Figure 3b showing the placement of a strip of membrane according to an embodiment of the invention to the adhesive, Figure 3c showing a full surround of the membrane around the whole window frame, and Figure 3d showing a further sealing stage to finish off.

[0035] Figure 1 shows in cross-sectional form, and not to scale, an embodiment of the present invention, with the layered structure of the embodiment visible. A sheet material 10 has a central layer of glass-fibre 12. Applied to one side of this is a continuous layer of silicone 14, this being a water based silicone, although other types may be used. The silicone is cured, and an aluminium foil layer 16 is applied to the other side of the glass-fibre layer 12, using a thin layer of silicone 18 to adhere the foil to the glass fibre. The sheet is formed as a continuous line, and once the silicone layer and adhesive are cured the sheet is rolled to provide a conveniently transportable unit. It may also be cut into rolls of smaller width, for different applications.

[0036] The glass-fibre layer has a specific weight of 430g / m2, and a thickness of between approximately 0.3mm and 0.5mm, although it will be appreciated that due to the fibrous nature of the layer the thickness may vary at different points across the sheet slightly. The glass-fibre sheet is a woven sheet made from fibres having a fibre size of approx. 9pm.

[0037] The silicone layer has a specific weight of 80g / m2, and the aluminium foil layer has a specific weight of 20g / m2. A sheet according to this specification has successfully passed testing to A2-s1, dO, according to British Standard BS EN 13501-1 for fire safety, and EN 13984 for water resistance.

[0038] In use, typical roll widths of between 50mm and 200mm are employed, to provide a seal with overlap around a joint. The width is typically chosen so as to provide coverage over a significant proportion, or all of, any horizontal flat surfaces such as window protrusions, where moisture may tend to lie. The width is also chosen to provide an overlap of a joint of typically 50mm to 200mm, although other overlaps may be used.

[0039] Figure 2 illustrates a typical application where embodiments of the invention may be used. Shown in the figure is a cutaway view of a section of wall where it joins a window frame. An aluminium extruded window frame 20 holds a glass window 22. The frame is attached to a steel frame inner wall 34 with an associated insulated panel 36, and sitting in front of this is a sheathing board 30. A wall of brick 24 provides an external face of the building. A line of silicone strip or bead 26 sitting between the brick fagade 24 and the window frame 20 provides a primary seal against ingress of moisture. Behind the brick outer skin, between it and the sheathing board 30 is a layer comprising of a cavity fire barrier 28 and mineral wool thermal insulation elements 31, 33. Sitting behind the mineral wool insulation 28 is the sheathing board 30 as stated earlier. A membrane 32 according to an embodiment of the invention is attached to both the window frame 20, and the sheathing board 30. The membrane 32 thus prevents, or provides a significant barrier to, any moisture ingress into the building through a join between the sheathing barrier 30 and the steel frame 20, or from contacting the steel frame 34, that may be present either from condensation or from ingress past the primary seal 26 and the thermal insulation 31, 33.

[0040] Attachment of a membrane according to an embodiment of the invention to a window frame and to a supporting structure (such as the inner skin of Figure 2) may be performed as shown in Figure 3. Figure 3a shows a window frame 40, holding a glass panel 42. The frame 40 protrudes from a supporting wall structure 44, and therefore has a horizontal surface at the top of the window frame, as is visible in Figure 3c. Although it is important to provide a seal around all points of possible ingress around the window frame, such as a join between different panels, it is particularly important where standing water can gather, such as at the top of the window frame.

[0041] It is assumed initially that a strip or roll of membrane material is available long enough to go around the circumference of the window frame, with some overlap, that is cut into strips each slightly longer than a side of the frame. Each strip has approx. 10cm width on each side of the join, and thus is, in this embodiment, 20cm in width. To attach a membrane, the first step is to apply an adhesive to both the frame, and to the supporting wall structure. The adhesive may be an oxime based silicone, or other suitable (preferably silicone) adhesive. It is first applied from a tube in one or two beads to the structure, as shown at 46 where it has been applied along a vertical aspect of the window frame. Once it’s been applied it is then trowelled to a wide, thin layer as shown at 48, preferably extending to at least the edge of where the membrane strip will sit. Once the adhesive has been applied and trowelled, the membrane is attached to the adhesive, on both sides of the joint being sealed, and is firmly pushed into the adhesive layer against the supporting structure using a roller. The membrane as shown in Figure 3b covers a right angle join, and thus has a fold line running along the joint, and in such cases it is advantageous to cut an overhang of the strip along the fold line, thus allowing the overhang to be applied both along the wall and along the adjoining side of the window frame.

[0042] Figure 3c shows the window frame 40 with all four sides thereof sealed, each done in similar fashion to that as described above. Note that for protruding elements such as this window it is preferable to apply the membrane to the underside first, then the two sides, and finally the top, so that overlaps between membrane strips will tend to have joints facing downwards.

[0043] Figure 3d shows the finishing stages to the installation. The window frame 40 has now had a covering of the membrane applied to all sides, and also to the surrounding wall. The final stage is a further application of the adhesive to all joints and boundaries, to ensure that there are no open edges where moisture may otherwise gather under the membrane.

[0044] Although shown above in applications for sealing joints between panels etc, another application for the sheet materials is as a wall covering, e.g. to totally cover a wall 12, particularly where the wall may be susceptible to ingress of moisture, such as a moisture permeable wall. Such sheets may typically be much wider reels, such as 1 ,5m in width Embodiments of the material may be used in other applications in the building and construction industry, as would be apparent to the normally skilled person.

[0045] It should be noted that embodiments of the invention, as well as providing a water resistance and fire resistance function, also help to insulate a building by preventing the flow of air currents though interfaces where it has been applied. This therefore helps to reduce the opportunity for interstitial or surface condensation forming from warm air that may otherwise be able to move from inside a building through to an external wall.

[0046] The functions described herein as provided by individual components could, where appropriate, be provided by a combination of components instead. Similarly, functions described as provided by a combination of components could, where appropriate, be provided by a single component.

[0047] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other additives, components, integers or steps.

[0048] Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0049] Features, integers, characteristics, or compounds, described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

[0050] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims1. A membrane for use as an interface sealing material in building and construction applications, the membrane comprising a layered sheet material, wherein the layers comprise at least a layer of glass-fibre sheet, a layer of silicone, and a metal foil layer, and wherein the percentage of silicone in the membrane is no more than 35% by weight.

2. A membrane as claimed in claim 1 wherein the silicone layer is attached to a first side of the glass-fibre sheet, and the metal foil layer is attached to a second side of the glass-fibre sheet.

3. A membrane as claimed in claim 2 wherein an additional silicone layer is attached to the foil layer, so that a silicone layer is present on each external surface.

4. A membrane as claimed in claim 1 wherein the foil layer is sandwiched between the glass-fibre layer and the silicone layer.

5. A membrane as claimed in claim 1 wherein the silicone layer is sandwiched between the metal foil layer and the glass-fibre layer.

6. A membrane as claimed in any of claims 1 to 4 wherein the metal foil layer is attached to the glass-fibre layer using an adhesive.

7. A membrane as claimed in claim 6 wherein the adhesive is a silicone or acrylic adhesive.

8. A membrane as claimed in claim 7 wherein, when the adhesive is a silicone adhesive, it has the same composition as that of the silicone layer.

9. A membrane as claimed in any of the above claims wherein the glass-fibre has a thickness of between 0.1mm and 1mm.

10. A membrane as claimed in any of the above claims wherein the glass-fibre has a specific weight of between 100 and 1000 g / m211. A membrane as claimed in claim 10 wherein the specific weight of the glass-fibre is between 400g / m2and 450g / m2.

12. A membrane as claimed in any of the above claims wherein the silicone layer has a specific weight of between 20g and 200g per m2.

13. A membrane as claimed in claim 12 wherein the silicone has a specific weight of approximately 80 g / m214. A membrane as claimed in any of the above claims wherein the metal foil is an aluminium foil.

15. A membrane as claimed in claim 14 wherein the aluminium foil has a specific weight of between 10g / m2and 50g / m2.

16. A membrane as claimed in claim 14 or 15 wherein the foil has a specific weight of approximately 20g / m2.

17. A membrane as claimed in any of the above claims wherein the membrane has undergone fire classification testing to A2-s1, dO, according to EN 13501-1.

18. A membrane as claimed in any of claims 1 to 16 wherein the ratio of silicone by weight making up the membrane is not more than 25%19. A membrane as claimed in any of claims 1 to 16 wherein the ratio of silicone by weight making up the membrane is approximately 14%20. A membrane as claimed in any of the above claims wherein the membrane has a resistance to water penetration of 2kPa for 24 hours according to EN 1928 under harmonised standard EN 13984, clause 5.5.

21. A method of making a membrane for use in the construction industry, comprising the steps of: a) producing a glass-fibre sheet; b) applying a silicone coating across a surface of the glass-fibre sheet;c) applying a metal foil either to the glass-fibre sheet with an adhesive or to the silicone coating.

22. A method for weather-sealing a part of a building from water ingress, comprising the steps of: a) taking a membrane as claimed in any of the appended claims; b) trimming as required the membrane so as to fit around a joint, feature or other element to be sealed; c) applying an adhesive to the joint, feature or other element to be sealed, the adhesive being trowelled to be relatively uniform and flat and to cover a region similar or slightly larger in size to the trimmed membrane; d) applying the membrane to the adhesive, and using a roller or press to push the membrane into the adhesive; e) applying a further quantity of adhesive over the border of the membrane and trowelling the bead to be a flat thin surface over the border;, to provide a weather-proof covering over the joint, feature or other element.

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