GB2579013A

GB2579013A - Building material

Info

Publication number: GB2579013A
Application number: GB1814194.5A
Authority: GB
Inventors: John Avril David; Ronald Murphy Robert; Ray Haynes Lesley
Original assignee: Don and Low Ltd
Current assignee: Don and Low Ltd
Priority date: 2018-08-31
Filing date: 2018-08-31
Publication date: 2020-06-10
Anticipated expiration: 2038-08-31
Also published as: GB201814194D0; GB2579013B

Abstract

The building material comprises a fabric, wherein at least a portion of the fabric is covered with an ultraviolet resistant (UV-resistant) material 40 suitable for constant or permanent UV exposure. The fabric may comprise a flexible rollable fabric. The material may be a roofing underlay. Only part of the upper surface of the fabric may be covered in UV resistant material wherein the UV protective part may be a band or strip 45 which is between 20-50cm. Also claimed is a method of making the material. Also claimed are kits including the material and a building with the material. The material may be adhesively bonding.

Description

BUILDING MATERIAL

FIELD OF INVENTION

The invention relates to a building material, and in particular, though not exclusively, to a roofing material such as a roofing underlay. The invention particularly, though not exclusively, relates to a building material, such as a roofing material, having improved ultraviolet (UV) resistance.

BACKGROUND TO INVENTION

Vapour permeable fabrics known in the art as possessing good barrier properties to water droplets and/or solid particles generally comprise a co-extruded or monolayer film layer comprising a plurality of micropores or a monolithic film. Such vapour permeable films may be used as roofing underlays due to their ability to assist in evacuating unwanted moisture from roof spaces. Generally these vapour permeable films which provide a barrier to the passage of water droplets are air barrier materials known as vapour permeable/air barrier roofing underlays Additionally synthetic vapour barrier fabrics are known in the art that also possess good water barrier properties that comprise a solid, barrier film layer comprising typically a blown, cast or extrusion coated film. Such vapour barrier synthetic underlays may be used as roofing underlays as a lightweight, cleaner alternative to traditional bitumen roofing felt. These vapour barrier synthetic underlays have the additional benefit of not becoming brittle at low temperature, a shortcoming of traditional bitumen roofing underlays.

According to EDANA (the European Disposables and Nonwovens Association), a nonwoven fabric is a sheet of filaments (continuous filaments), fibres or chopped yarns of any nature or origin that have been formed into a web by any means, and bonded together by any means with the exception of weaving or knitting.

Nonwovens typically have specific characteristics which can be selectably engineered dependent upon end use, e.g. moisture vapour permeability, gas/air permeability, liquid impermeability, resilience, stretch, softness, strength, flame retardancy, washability, cushioning and/or filtering.

A spunlaid nonwoven (also referred to herein as a spunbond fabric) comprises a spunlaid web. A spunbond or spunlaid nonwoven material is formed of continuous filaments, typically having a filament diameter greater than 15 micron (pm). A meltblown nonwoven material is comprised of discontinuous fibres, typically having a fibre diameter 2.5 micron (pm) or greater. The spunlaid web can be bonded by one or more techniques to provide fabric integrity. One such technique is point-bonding (e.g. thermal calender point bonding) which typically uses heat and pressure in a predetermined discrete (point) pattern to bind thermoplastic filaments or fibres to form a (self-supporting) nonwoven fabric. The filament or fibres of nonwoven fabrics typically comprise polymers or thermoplastics, e.g. polypropylene or alternatively polyethylene or polyester.

A microporous film is a continuous film that contains a high percentage of calcium carbonate filler particles. By stretching this film, either mono or bi axially, creates interconnected micropores around these filler particles. This leads to a film that is an air barrier whilst also being vapour permeable.

Composite vapour permeable structures or "laminates" comprise two or more layers of nonwovens, with each nonwoven component playing a prevalent role. Such laminates typically have an "SM" structure in which a spunbond layer is laminated to a meltblown layer, or an "SMS" structure in which a meltblown layer is sandwiched between two spunbond layers. Typical air and vapour permeable underlay fabrics include nonwoven laminated materials comprising a meltblown layer, such as those described in EP 0 742 305 Al (Don & Low Limited).

Alternatively, vapour permeable laminates can incorporate a microporous film inner layer, sandwiched between 2 outer spunbond layers. In this instance the microporous film is an air barrier, whilst being vapour permeable. Typical air barrier and vapour permeable underlay fabrics include nonwoven laminated materials comprising a microporous film layer, such as those described in EP 0 570 215 (Don & Low Limited).

Alternatively, composite vapour barrier and air barrier structures or "laminates" may comprise two or more layers of nonwovens, with each nonwoven component playing a prevalent role. Such laminates typically incorporate an air and vapour barrier film in which a spunbond layer is laminated to a blown or cast synthetic barrier film. Alternatively the air and vapour barrier film can be applied to the spunbond via an extrusion coated process.

Synthetic roof tile underlays, typically made of a polyolefin material, are widely used as underlays in pitched roofing. These materials are lightweight, strong and are designed to be sufficiently UV stable to allow for the short term UV exposure that occurs during the installation phase of an underlay, i.e., prior to installation of the roof files or slates. However, the bottommost layer of underlay typically extends beyond the protection/coverage provided by the edge of the tiles or slates and into the gutter. As such, this bottommost layer of underlay is subjected to permanent UV exposure. Industry guidance, relating to slating and tiling for pitched roofs, recommends that where the underlay is likely to be permanently exposed, e.g. at the eaves and bottom edge of the roof, the underlay should be permanently UV-resistant.

The European standard for roofing and walling underlays is EN 13859. This standard contains a requirement for accelerated UV ageing testing of underlays (using test method EN1297 entitled "Flexible sheets for waterproofing -Bitumen, plastic and rubber sheets for roof waterproofing -Method of artificial ageing by long term exposure to the combination of UV radiation, elevated temperature and water"). The EN13859 standard identifies two categories of underlay, as follows: * Underlays designed for temporary UV exposure, such as synthetic roof file underlay. Such underlays must resist artificial aging by exposure to UV radiation for 336 hours in an accelerated ageing UV test chamber using a UVA light source at 50°C, corresponding to a total UV radiant exposure of 55 MJ/m2; and * Materials designed for permanent UV exposure, such as the integral eaves strip. Such underlays must resist artificial aging by exposure to UV radiation for 5,000 hours in an accelerated ageing UV test chamber using a UVA light source at 50°C, corresponding to a total UV radiant exposure of 818 MJ/m2.

To comply with these recommendations it is common practice to install a lowermost layer (layer on the roof adjacent the eaves) of underlay which is different from the underlay used to cover the rest of the roof. This bottom layer of underlay comprises a UV-resistant material, such as bitumen roofing felt. This layer can then be dressed into the gutter as it is suitable for permanent UV-exposure. Another variant includes eaves protection trays formed from UV-resistant plastics fitted horizontally at the eaves.

These UV-resistant layers protect the roofing underlay at the eaves, thus preventing long-term degradation of the underlay. These eaves protection strips are important for ensuring that the integrity of the roofing system is not compromised by a failure of the synthetic polyolefin underlay by premature ageing due to UV exposure.

Thus, when synthetic polyolefin roofing underlays are used below slating and filing, common practice is to introduce a separate UV-resistant eaves tray or UV-resistant bituminous underlay, which is suitable for permanent UV exposure. While this generally provides the required UV resistance in the exposed areas, typically at or near the eaves of a roof, this approach can also cause one or more of the following problems: * Incompatibility with bituminous products: Some synthetic underlays are microporous, i.e. they are vapour permeable whilst being water resistant.

These micropores can be compromised by low surface tension liquids, such as oil-based materials, resulting in a loss of water resistance. As bitumen, a material typically used as a eaves strip, is derived from hydrocarbons and the two material types are permanently lapped together on the roof, bituminous residues can leech out and transfer to the synthetic underlay, potentially compromising the performance of the adjacent synthetic vapour permeable underlay; * Installation issues: The installation of two different types of underlay can be complicated, in particular sourcing two appropriate and compatible materials. In addition, there is the potential for these two underlay products to be wrongly installed. For example, if the upper synthetic membrane is positioned below the UV resistant membrane, any draining moisture will be directed into the roof space and building rather than towards the external gutters; * Coordination issues: The installation of these two separate components, i.e. the synthetic roofing underlay and the UV-resistant eaves tray (or strip), is often undertaken by two separate contractors: the synthetic underlay by the roofing contractor when battening and tiling, and the eaves tray or strip by the contractor responsible for installing the guttering. This requires effective coordination between these two contractors, which may cause delay in completion of the root Another minimum requirement for roofing underlays is to achieve class W1 water tightness under test EN 1928 According to EN1928, a static test pressure of 200 mm water is applied on the upper side of the specimen for 2 hours. At the end of the test there should be no leakage through to the underside of the underlay. This test is typically applied before and after artificial ageing and must be passed Typical roofing underlays would not pass EN 1928 after artificial ageing for 5000 hrs.

Another and more stringent test for measuring water tightness performance is EN 20811. EN 20811 is a dynamic water hold out test, in which a specimen is subjected to a given hydrostatic pressure ('head') of water. Typical roofing underlays would not pass EN 20811 under a hydrostatic head of 3000mm after artificial ageing for 5000 hrs.

It is an object of at least one embodiment of at least one aspect of the present invention to obviate or at least mitigate one or more problems or disadvantages in the

prior art.

SUMMARY OF INVENTION

According to a first aspect of the invention there is provided a building material comprising a fabric or textile, wherein at least a portion of the fabric or textile is covered with an ultraviolet resistant (UV-resistant) material.

The fabric may comprise or may be a synthetic fabric. The fabric may comprise or may be a polymeric fabric. The fabric may be a flexible fabric.

The fabric may comprise or may be a flexible rollable fabric.

The building material may be flexible and/or rollable.

The UV-resistant material may form or may define a "weather strip".

The term "UV-resistant material" will be herein understood to mean that the material may be suitable for long-term and/or constant exposure to UV radiation, e.g., UV radiation from sunlight. Thus, the portion of the building material comprising the UV-resistant material may be suitable for long-term and/or constant exposure to UV radiation, e.g., UV radiation from sunlight. The "UV-resistant material" may be capable of maintaining one or more properties, e.g., physical integrity, tensile strength, water holdout, or the like, following long-term and/or constant exposure to UV radiation, e.g., UV radiation from sunlight The UV-resistant material and/or the portion of the building material comprising the UV-resistant material may be considered UV resistant according to EN 13859 standard. Testing may be carried out by exposing the material to the standard UV accelerated ageing conditions at elevated temperature, according to test method EN 1297 The UV-resistant material and/or the portion of the building material comprising the UV-resistant material may be considered UV resistant for temporary UV exposure following artificial aging by exposure to UV radiation for at least 336 hours in an accelerated ageing UV test chamber using a UVA light source at 50°C, which may correspond to a total UV radiant exposure of at least 55 MJ/m2 Preferably, the UV-resistant material and/or the portion of the building material comprising the UV-resistant material may be considered UV resistant for permanent UV exposure following artificial aging by exposure to UV radiation for at least 5000 hours in an accelerated ageing UV test chamber using a UVA light source at 50°C, corresponding to a total UV radiant exposure of at least 818 MJ/m2.

The UV-resistant material and/or the portion of the building material comprising the UV-resistant material may achieve class W1 water tightness under test EN 1928, for example when a static test pressure of 200 mm water is applied on the upper side of the specimen for 2 hours. The UV-resistant material and/or the portion of the building material comprising the UV-resistant material may achieve class W1 water tightness under test EN 1928, for example when a static test pressure of 200 mm water is applied on the upper side of the specimen for 2 hours, following artificial ageing under UV exposure for at least 5000 hours according to EN 13859 standard.

The UV-resistant material and/or the portion of the building material comprising the UV-resistant material may be considered watertight under a hydrostatic head of at least 2000 mm, e.g. at least 2500 mm, e.g. at least 3000 mm, for example when tested to EN 20811 Standard. The UV-resistant material and/or the portion of the building material comprising the UV-resistant material may be considered watertight under a hydrostatic head of at least 2000 mm, e.g. at least 2500 mm, e.g. at least 3000 mm, for example when tested to EN 20811 Standard, following artificial ageing under UV exposure for at least 5000 hours according to EN 13859 standard.

The UV-resistant material may form or may be provided as a layer, e.g. a single layer or multi-layer structure, covering at least a portion of the fabric. In such instance, at least a portion of the fabric may be covered with a UV-resistant layer, e.g. mono-or multi-layer.

The UV-resistant material may be provided in the form of a separate layer (e.g. a single layer or multi-layer structure), e.g. as a self-supported layer such as a sheet or film, which may be combined with the fabric. The UV-resistant material may be laminated to the fabric. The UV-resistant material may be bonded, glued or adhered, e.g. by use of an adhesive or glue, to the fabric. The UV-resistant material may be attached to the fabric, e.g. by stitching or the like.

The UV-resistant material may be applied to the fabric, for example, in molten form or liquid (e.g. dissolved or dispersed) form. The UV-resistant material may be extrusion coated on the fabric. The UV-resistant material may be coated, e.g. spray-coated, on the fabric.

The UV-resistant material may comprise a UV-resistant polymeric material, e.g. a UV-resistant polyolefin material or polyester. The UV-resistant material may comprise a polypropylene homo-or co-polymer. The UV-resistant material may comprise a polyethylene homo-or co-polymer, e.g. Linear Low Density Polyethylene (LLDPE).

The UV-resistant material may comprise one or more additives such as carbon black, UV stabilizers and/or thermal stabilizers.

The UV-resistant material may be provided as a single layer.

Alternatively, the UV-resistant material may comprise a plurality of layers, e.g. may comprise two or more layers.

The UV-resistant material may comprise a first layer which is configured to provide UV resistance. The first layer may be provided on an upper or outer side of the building material.

The UV-resistant material may comprise a second layer, e.g. a bottom layer provided on a lower side of the first layer, provided to allow the UV-material to bond to a substrate, e.g. to the fabric.

When the UV-resistant material is made of two layers, the first layer may define an upper layer.

It will be understood that the terms "upper", "outer", "lower', "inner", "bottom", etc, used in conjunction with the first layer and/or the second layer refer to the relative position of such layers in use, for example with reference to a building structure such as a roof. For example, when used on a roof or roof structure, the term "upper side" or "outer side" may refer to a side of the fabric opposite an inside space of the roof, and the terms the term "lower side" or "inner side" may refer to a side of the fabric facing an inside space of the the roof.

The UV-resistant material may comprise one or more additional layers. The one or more additional layers may be provided on an upper side of the second layer, e.g., on either side or both sides of the first layer, which may be provided to give the UV-resistant material any desired properties to suit various applications, e.g. waterproofness, scratch resistance, etc. The second layer may comprise, may consist of or may consist essentially of a material having a melt temperature lower than the melt temperature of the first layer.

By such provision, upon lamination of the UV-resistant material to the synthetic fabric, the second layer may act as a bonding layer. The second layer may comprise a low melting point polymer, e.g. may comprise a polyethylene polymer such as Linear Low Density Polyethylene (LLDPE).

The first layer may comprise, may consist of or may consist essentially of a material having a melt temperature higher than the melt temperature of the second layer, e.g. higher than the melt temperature of polyethylene or LLDPE. By such provision, upon lamination of the UV-resistant material to the fabric, the first layer may be prevented from melting, degrading, or losing structural integrity. The first layer may comprise, may consist of or may consist essentially of a polypropylene polymer, e.g. polypropylene (PP). Typically, the first layer may comprise at least one UV stabiliser, including for example hindered amine light stabilisers (HALS). The first layer may comprise one or more further additives such as carbon black, thermal stabilisers, and the like.

When the UV-resistant material is provided as a single layer, the first layer may form or may define the single layer and/or the UV-resistant material.

The UV-resistant material, first layer and/or second layer may be selected to allow autogenous bonding or laminating with the fabric (synthetic roofing underlay).

The fabric may be a roofing material such as roofing underlay. The fabric may have a mono-layer or single layer structure. The fabric may have a multilayer or laminated structure.

The fabric may be vapour permeable. The fabric may not be vapour permeable. The fabric may include an air and vapour-permeable meltblown layer. The fabric may include an air barrier and vapour-permeable microporous film layer. The fabric may include an air barrier and vapour barrier film layer.

The fabric may be or may comprise a spunbond-meltblown "SM" structure. The fabric may be or may comprise a spunbond-meltblown-spunbond "SMS" structure. The fabric may comprise a layer of meltblown material having an average pore size diameter in the range of 1 -10 pm. The fabric may comprise a layer of spunbond material having an open pore structure. The fabric may be or may comprise a synthetic fabric as described in EP 0 742 305 Al (Don & Low Limited), the content of which is incorporated herein by reference in its entirety.

The fabric may include or may consist of a microporous film inner layer, sandwiched between 2 outer spunbond layers. The fabric may be or may comprise a synthetic fabric as described in EP 0 570 215 (Don & Low Limited), the content of which is incorporated herein by reference in its entirety.

The fabric may comprise a spunbond layer on an upper side thereof. The UV-resistant material may be provided or applied on a spunbond layer of the fabric. The fabric may comprise or may consist of a single spunbond layer. The fabric may comprise or may consist of a laminate structure comprising at least one spunbond layer, wherein the UV-resistant material may be provided or applied to at least one spunbond layer.

The UV-resistant material, e.g. UV-resistant layer, may typically have an area weight in the range of about 20-100 gsm, e.g. 30-60 gsm, e.g. 40-50 gsm, e.g. about 46 gsm. The UV-resistant material, e.g. UV-resistant layer, may typically have an area weight in the range of about 20-100 gsm, e.g. 30-60 gsm, e.g. 40-50 gsm, e.g. about 46 gsm, as measured before lamination to the synthetic fabric.

The UV-resistant material, e.g. UV-resistant layer, may typically have a thickness in the range of about 25-75 pm. e.g. 40-60 pm, e.g. about 50 pm. The UV-resistant material, e.g. UV-resistant layer, may typically have a thickness in the range of about 25-75 pm. e.g. 40-60 pm, e.g. about 50 pm, as measured before lamination to the synthetic fabric.

Typically, roofing underlay may be provided in the form of a roll. The roll may have a length and a width. Typically, during installation on a pitched roof (i.e. not a flat roof), a roll of underlay is unrolled along a width of the roof from one side of the roof to an opposite side, starting from a lower section of the roof and finishing at an upper section of the roof with an overlap between adjacent layers of overlay to ensure any water ingress through the tiles does not penetrate the roofing underlay structure, but instead runs down the underlay following the pitch of the roof into the gutter.

The UV-resistant material may be provided on or may cover part of the fabric.

The UV-resistant material may be provided on or may cover part of a surface, e.g. an upper surface, of the fabric. The building material and/or fabric may have a surface, e.g. upper surface, wherein part of the fabric, e.g. upper surface thereof, is covered by the UV-resistant material, and part of the fabric, e.g. upper surface thereof, is not covered by the UV-resistant material.

Advantageously, in the building material, the UV-resistant material may be provided along at least part of a length of the fabric. The UV-resistant material may define a strip or band that extends along at least part of a length, e.g. along the entire length, of the building material. By such provision, upon installation, the roll may be applied thus providing a strip or band of UV-resistant material in the region of the roofing underlay that may be exposed, e.g. permanently exposed, to UV radiation, such as at or near the eaves of a roof. Advantageously, because the building material is made of the same fabric as the remainder of the roofing underlay structure, there is no risk of incompatibility between materials used. In addition, the use of an integrated product simplifies the installation process by requiring a single contractor, thereby reducing the potential for installation errors and coordination difficulties.

Typically, the building material, e.g. roofing underlay, may have a width up to 3m, e.g. about 1-3m, typically about 1-1.5m, e.g. about 1.5m. The UV-resistant material may form or may define a strip or band having a width of about 20-50cm, e.g. about 30-40cm.

Advantageously, the UV-resistant material, e.g. strip or band, may be provided along a longitudinal edge of the fabric.

It will be understood that the specific size, e.g. width, of the UV-resistant material on the synthetic fabric may depend on the specific application, including for example the amount of building material expected to be exposed to UV radiation, and the overall dimensions of the building material. Advantageously, by providing a strip or band of UV-resistant material to the synthetic fabric, e.g. along a longitudinal edge thereof, adequate UV resistance may be achieved in the required areas, while limiting any adverse effect that the UV-resistant material may have on the performance and/or properties of the synthetic fabric, such as breathability, vapour permeability, porosity, flexibility, total product weight, product cost, etc, to the region, e.g. strip or band, on which the UV-resistant material is applied to the fabric. Thus, in use, the remainder of the fabric (which is devoid of or not covered by UV-resistant material) may be covered by tiles or slates and/or may continue to offer all the benefits and features associated with synthetic roofing underlays.

Conveniently, the width of the building material, e.g. of a roll thereof, may be different from, e.g. larger than, the width of a/the (uncoated) fabric, e.g. of a roll thereof.

By such provision, a user, e.g. supplier or contractor, may easily be able to identify a roll of the building material when stored or located near or with rolls of a/the (uncoated) fabric. For example, the width of the uncoated fabric in the material may be the same as or similar to a/the width of the conventional uncoated fabric, and the entire width of the building material may be equal to the width of the uncoated fabric plus the width of the UV-resistant material.

Alternatively, the width of the building material, e.g. of a roll thereof, may be the same as or similar to the width of a/the (uncoated) fabric, e.g. of a roll thereof.

According to a second aspect of the present invention there is provided a method of manufacturing a building material, the method comprising: providing a fabric-and applying a UV-resistant material to or on at least a portion of the fabric.

The fabric may comprise or may be a flexible rollable fabric The fabric may be a roofing material such as roofing underlay. The fabric may have a laminated structure.

The method may comprise applying the UV-resistant material to the fabric in molten form or liquid (e.g. dissolved or dispersed) form.

The method may comprise extrusion coating the UV-resistant material onto the fabric In such instance, the method may comprise passing a molten polymer composition, e.g. a polymer composition intended to act as the UV-resistant material, through an extruder and applying it as a thin film through a slotted die to the synthetic fabric, e.g. underlay.

The method may comprise coating, e.g. spray-coating, the UV-resistant material onto the fabric.

The method may comprise providing the UV-resistant material as a self-supporting material, e.g. as a film or sheet.

The method may comprise laminating the UV-resistant material to the fabric. The method may comprise passing the UV-resistant material and the fabric through thermal calender bonding rollers. Typically, when the UV-resistant material and the fabric are made of polyolefins, e.g. polyethylene and/or polypropylene, both layers may have similar melting points, thus allowing effective thermal bonding via lamination. The method may comprise laminating through a smooth calender roller and an embossed calender roller. Typically, the embossed roller may be in contact with the fabric, e.g. roofing underlay. The smooth roller may be in contact with the UV-resistant material, e.g. film. Alternatively, the method may comprise laminating through a plurality of, e.g. two, flat or smooth calender rollers The lamination of the UV-resistant material may take place on the spunbond line during the manufacture of the uppermost spunbond layer for the fabric, e.g. roofing underlay, or it may be added to the finished fabric, e.g. roofing underlay, in a separate lamination stage. It will be appreciated that the lamination temperatures for laminating on-line will be dependent on the process temperatures for the weight of spunbond layer being manufactured.

When using a separate lamination stage, the temperature of the roller in contact with the fabric may be in the region of about 120-150°C, e.g. about 130-140°C, e.g. about 135°C. The temperature of the roller in contact with the UV-resistant material, e.g. film, may be in the region of about 80-100°C, e.g. about 90°C.

The calender pressure may be in the region of about 60-100N/mm, e.g. about 60-100N/mm, e.g. about 80N/mm. The speed of the laminator may be set at about 1215 m/min, e.g. about 15 m/min.

A person of skill in the art will understand that the specific conditions under which lamination is carried out will depend upon the chemical properties, e.g. chemical composition, physical properties, e.g melt temperature, and/or dimensions, e.g. thickness, of the materials used for the synthetic fabric and/or UV-resistant material. The method may comprise bonding, e.g. using an adhesive, the UV-resistant material, e.g. film, to the fabric. The method may comprise applying an adhesive to one or both of the UV-resistant material, e.g. film, and the fabric. The method may comprise bringing a surface of the UV-resistant material, e.g. film, and of the fabric, preferably a surface thereof provided with adhesive, together. The method may comprise applying pressure. The method may comprise curing the adhesive.

It will be appreciated that the features described in relation to the first aspect of the invention may equally apply to the method according to the second aspect, and are not repeated here merely for reasons of brevity.

According to a third aspect of the invention there is provided a building or building structure comprising a building material according to the first aspect, or made or obtainable by the method according to the second aspect of the present invention.

The building structure may comprise or may be a roof. The roof may be an unsupported roof, such as an unsupported cold or warm pitched roof and/or a non-vented roof, e.g. a non-vented cold pitched roof. Alternatively the roof may be a fully supported (sarked) roof.

An unsupported roof may comprise a laminated fabric, in particular a roofing underlay, draped between rafters in a roof (hence the underlay is termed as being unsupported'). Battens may be placed on top of the underlay onto which the tile and slates may be secured A non-vented roof is a roof in which there are no mechanical vents incorporated into the roof design, e.g. no mechanical vents at the eaves or ridges of the roof.

A fully supported or sarked roof may comprise boards or sheets placed onto rafters. In such embodiments, the laminated fabric may be placed directly on the rigid upper surface of the boards or sheets (hence the underlay is termed as being supported').

It will be appreciated that the features described in relation to the first aspect or the second aspect of the invention may equally apply to the building or building structure according to the third aspect, and are not repeated here merely for reasons of brevity.

According to a fourth aspect of the present invention there is provided a use of a material as defined in the first aspect or made or obtainable by the method according to the second aspect, as a building material.

Typically, the building material may be used as a roofing underlay.

It will be appreciated that the features described in relation to the first, second or third aspect of the invention may equally apply to the use according to the fourth aspect, and are not repeated here merely for reasons of brevity.

According to a fifth aspect of the present invention there is provided a kit comprising: (a) a first roll of building material according to a first aspect of the present invention or obtainable by a method according to the second aspect of the present invention, the first roll having a first width; (b) a second roll of building material, the second roll having a second width; wherein the first width is greater than the second width.

The second roll of building material may be or may comprise an uncovered fabric, e.g. a fabric devoid of the UV-resistant material.

By such provision, a user, e.g. supplier or contractor, may easily be able to identify a roll of the first roll of building material when stored or located near or with rolls of a/the (uncoated) fabric/textile. For example, the width of the uncoated fabric in the material may be the same as or similar to a/the width of the conventional uncoated fabric, and the entire width of the first roll of building material may be equal to the width of the uncoated fabric plus the width of the UV-resistant material or strip.

It will be appreciated that the features described in relation to any of the first, second, third or fourth aspect of the invention may equally apply to the kit according to the fifth aspect, and are not repeated here merely for reasons of brevity.

More generally, it is to be appreciated that any feature described in connection with one or more aspect or embodiment of the invention, may equally apply to any other aspect of the invention without departing from the scope of the invention.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present invention will now be described by way of example only, and with reference to the accompanying drawings, which are: Figure 1 a conventional pitched roofing underlay construction near an eaves

region of a roof, according to the prior art;

Figure 2 a roofing underlay construction near an eaves region of a roof, according to an embodiment of the present invention; Figure 3 a schematic representation from above of a building material according to an embodiment of the present invention; Figure 4 19 Figure 5 a schematic perspective view of the a roll of the building material of Figure 3; Figure 6 a perspective view of a roofing underlay construction near a valley gutter region of a roof, according to an embodiment of the present invention; and a cross-sectional view of the roofing underlay construction of Figure 5.

DETAILED DESCRIPTION OF DRAWINGS

Referring to Figure 1, there is shown a conventional roofing underlay construction 20 near an eaves region 12 of a roof 10, according to the prior art. The roofing construction 20 has a gutter 22 near an eaves region 12 thereof. The roofing construction 20 has a layer of roofing underlay 25. Although one row of underlay 25 is shown for clarity, it will be understood that a number of rows are provided in order to cover the entirety of the roof surface, each row overlapping a lower row so as to prevent any water ingress. The roofing underlay 25 is typically provided underneath files or slates, which are not shown here for clarity.

In this embodiment, roofing underlay 25 is made of a laminated membrane provided as a polypropylene structure incorporating an air and vapour permeable meltblown layer, an air barrier and vapour permeable microporous film layer or an air barrier and vapour barrier film layer. In the eaves region 12, the lowermost layer 26 of underlay is made of a different material from the roofing underlay 25. The lowermost layer 26 is made of a bitumen roofing felt which provides permanent UV resistance. Thus, layer 26 can be dressed into the gutter 22 as it is suitable for permanent UV exposure without degradation.

Figure 3 shows a schematic representation from above of a building material 30 according to an embodiment of the present invention. Figure 4 shows the building material of Figure 3, in the form of a roll 35.

The building material 30 may include laminated nonwoven spunbond layers incorporating either a vapour permeable or vapour barrier inner layer. In this embodiment, the building material 30 includes a "SMS" polypropylene membrane 32. However, the membrane 32 is partially covered by a UV-resistant material 40. In this embodiment, the UV-resistant material is provided in the form of a strip 45 provided along the length of the membrane 32. In this embodiment, the UV-resistant material 40 is provided along one of the longitudinal edges 33 of the membrane 32. By such provision, upon installation, for example on a roof, the roll 35 may be applied as roofing underlay thus providing a strip or band 45 of UV-resistant material 40 in the region of the roofing underlay that may be exposed, e.g. permanently exposed, to UV radiation, such as at or near the eaves region 12 of the roof 10. The strip 45 designed for permanent UV exposure is permanently attached to the nonwoven membrane 32.

This is best shown in Figure 2, which shows an eaves region 112 of a roof 110, similar to Figure 1, like parts being denoted by like numerals, incremented by '100'. In Figure 2, the roofing construction 120 includes a lowermost layer 126 at the eaves region 112 of the roof 110, and a layer of roofing underlay 125 partially overlapping the lowermost layer 126. In Figure 2, the lowermost layer 126 consists of the building material 30 according to an embodiment of the present invention as depicted in Figures 3 and 4. As shown in Figure 2, the building material 30 is installed such that the strip or band 45 of UV-resistant material 40 is disposed in the region of the roofing underlay that is likely to be exposed, e.g. permanently exposed, to UV radiation, that is, as at or near the eaves region 112 of the roof 110. However, the region 36 of the material 30 free of UV-resistant material 40 allows the roofing underlay to maintain the normal performance and properties of the membrane 32 where permanent UV-resistance is not required. In this embodiment, the roofing underlay 125 provided above and partially overlapping the lowermost layer 126, consists of the same membrane 32 used in the building material 30 of figures 3 and 4, but without the UV-resistant material 40. By such provision, because compatibility between the lowermost layer 126 and the roofing underlay 125, and ease of installation, is improved.

Figures 5 and 6 show a roofing construction 220 according to another embodiment of the present invention, in which the building material 30 of Figures 3 and 4 is used at a valley gutter region 214 of a roof 210. Typically, this region 214 has a preformed valley gutter 250 (often made of a GRP material) which, near an upper region thereof, is covered by a lead saddle flashing 252 dressed over the preformed valley gutter 250. As best shown in Figure 6, the roofing underlay 225 is typically draped onto the preformed valley gutter 250. While the underlay 225 is normally protected by the overhanging (lower) tiles or slates 254, there remains a risk of exposure to UV radiations, e.g. through direct sunlight, in this region 214. Therefore, in this embodiment, the underlay 225 in the valley gutter region 214 of a roof 210 consists of the building material 30 of Figures 3 and 4, such that the lowermost region of the underlay 225 has a strip or band 45 of UV-resistant material 40. Tests

The UV resistance of (i) a synthetic roofing underlay and (ii) an underlay covered with UV resistant integral eaves strip, was tested.

The "conventional" synthetic roofing underlay was a 3-layer polypropylene "SMS" laminate membrane.

The UV-resistant roofing underlay was as shown in Figures 3 and 4, described earlier, namely a "SMS" polypropylene laminate membrane, but covered along one of its longitudinal edges by a UV-resistant film consisting of thermo-bondable polypropylene containing HALS UV stabilisers and carbon black pigment to act as a UV absorber.

Testing was carried out by exposing each material to the standard UV accelerated ageing conditions at elevated temperature, according to test method EN 1297. The key properties for roofing underlay of water hold out Resistance to water penetration BS EN 20811 (under a hydrostatic head of 3000mm) and tensile strength measured by EN 12311-1 Tensile Properties. Both properties were measured before and after artificial ageing for 5000 hrs to the EN13859-2 Standard (for materials not excluded from UV exposure). Providing the underlay continued to demonstrate acceptable performance, post ageing, for both these properties then this was assessed as a 'pass'.

The results are shown in the Table 1 below:

Table

UV Exposure Period Synthetic Roof Tile Synthetic Roof Tile Accelerated Ageing Underlay Underlay with bonded Chamber integral Eaves strip 336 hours Pass Pass 5,000 hours Fail Pass It can be seen from Table 1 that conventional synthetic underlays give good performance when aged for temporary UV resistance but poor performance when subjected to permanent UV exposure. This is expected as polypropylene synthetic roof tile underlays are only designed for temporary UV exposure However, it can be observed that the addition of a UV-resistant strip 45 along one longitudinal edge of the roll 35 greatly improves performance when subjected to accelerated ageing designed to replicate permanent UV exposure, including water holdout and tensile strength.

It will be appreciated that the embodiments if the present invention hereinbefore described are given by way of example only, and are not meant to be limiting to the scope of the invention in any way.

Claims

CLAIMS1. A building material comprising a fabric, wherein at least a portion of the fabric is covered with an ultraviolet resistant (UV-resistant) material suitable for long-term UV exposure.
2. A building material according to claim 1, wherein the fabric comprises a flexible rollable fabric.
3. A building material according to either of claims 1 or 2, wherein the UV-resistant material and/or the portion of the building material comprising the UV-resistant material is UV-resistant after artificial ageing for at least 5000 hours (according to EN 13859 Standard and/or in an accelerated ageing UV test chamber using a UVA light source at 50°C corresponding to a total UV radiant exposure of 818 MJ/m2).
4. A building material according to any preceding claim, wherein the UV-resistant material and/or the portion of the building material comprising the UV-resistant material is watertight under static test pressure of 200 mm water for 2 hours (optionally according to EN 20811 Standard), and/or wherein the UV-resistant material and/or the portion of the building material comprising the UV-resistant material is watertight under a hydrostatic head of at least 3000 mm (optionally according to EN 20811 Standard).
5. A building material according to any preceding claim, wherein the UV-resistant material forms a layer covering at least a portion of the fabric.
6. A building material according to any preceding claim, wherein the UV-resistant material is provided in the form of a separate layer which is combined with the fabric, optionally laminated, bonded, glued, adhered or attached to the fabric.
7. A building material according to any preceding claim, wherein the UV-resistant material comprises a UV-resistant polymeric material.
8 A building material according to any of claims 1 to 7, wherein the UV-resistant material comprises at least one layer or a single layer.
9. A building material according to any of claims 1 to 7, wherein the UV-resistant material comprises a plurality of layers.
10. A building material according to claim 9, wherein the UV-resistant material comprises a first layer which is configured to provide UV resistance and provided on an upper or outer side of the building material, and a second layer provided on a lower or inner side of the first layer to allow the UV-material to bond to the fabric.
11. A building material according to claim 10, wherein the second layer comprises, consists of or consists essentially of a material having a melt temperature lower than the melt temperature of the first layer.
12. A building material according to any preceding claim, wherein the fabric is a roofing material, optionally a roofing underlay.
13. A building material according to any preceding claim, wherein the material is provided in the form of a roll or rolled goods.
14. A building material according to any preceding claim, wherein the fabric has an upper or outer surface, wherein part of the fabric upper surface is covered by the UV-resistant material, and part of the fabric upper surface is not covered by the UV-resistant material.
15. A building material according to any preceding claim, wherein the UV-resistant material is provided along at least part of a length of the fabric and/or wherein the UV-resistant material defines a strip or band that extends along at least part of a length of the building material.
16. A building material according to any preceding claim, wherein the building material has a width of about 1-3m, and the UV-resistant material forms or defines a strip or band having a width of about 20-50cm.
17. A building material according to any preceding claim, wherein the UV-resistant material is provided along a longitudinal edge of the fabric, optionally as a strip.
18. A method of manufacturing a building material, the method comprising: providing a fabric; and applying an ultraviolet resistant (UV-resistant) material to or on at least a portion of the fabric.
19. A method of manufacturing a building material according to claim 18, the method comprising applying the UV-resistant material to the fabric in molten form or liquid form.
20. A method of manufacturing a building material according to claim 18, the method comprising extrusion coating the UV-resistant material onto the fabric.
21. A method of manufacturing a building material according to claim 18, the method comprising laminating the UV-resistant material to the fabric.
22. A method of manufacturing a building material according to claim 18, the method comprising bonding, optionally as autogeneously or adhesively bonding, the UV-resistant material to the fabric.
23. A building or building structure comprising a building material according to any of claims 1 to 17.
24. A building or building structure according to claim 23, wherein the building structure is a roof, optionally a pitched roof.
25. Use of a material as claimed in any of claims 1 to 17 or obtainable by the method according to any of claims 18 to 22, as a building material, optionally as a roofing material.
26. A kit comprising: (a) a first roll of building material according to any one of claims 1 to 17 or obtainable by a method according to any of claims 18 to 22, the first roll having a first width; and (b) a second roll of building material, the second roll having a second width; wherein the first width is greater than the second width.
27 A building material comprising a fabric, wherein at least a portion of the fabric is covered with an ultraviolet resistant (UV-resistant) material.