apour Barrier and Waterproof Thermal Insulation Aluminium Foil Membrane - Suitable for use in Walls, Floors and Roofs - 1.5m x 50m (75 SQ/M) - 110 G/SM - Free Next Day UK Delivery - Large Discounts Available on Multi Pack (1)

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The films are available in various sizes and lengths and can be optimally adapted to any structure. Multilayer metallization films are particularly suitable. They reflect the heat energy and form an additional insulating effect. The industry has recognized that in many circumstances it may be impractical to design and build building assemblies which never get wet. Good design and practice involve controlling the wetting of building assemblies from both the exterior and interior. [3] So, the use of vapor barrier should be taken into consideration. Their use has already been legislated within the building code of some countries (such as the U.S., Canada, Ireland, England, Scotland & Wales). How, where, and whether a vapor barrier (vapor diffusion retarder) should be used depends on the climate. Typically, the number of heating degree days (HDD) in an area is used to help make these determinations. A heating degree day is a unit that measures how often outdoor daily dry-bulb temperatures fall below an assumed base, normally 18°C (65°F). [4] A subarctic and arctic climate is defined as a region with approximately 12,600 heating degree days (65 degrees F basis) [7,000 heating degree days (18 degrees C basis)] or greater. With three layers of polypropylene reinforced heavy laminated foil, this SFTV barrier is equipped with commendable reflective properties to benefit its U-value. It creates an 'airtight' layer for the entire building envelope and, in turn, enhances energy performance in both new and retrofit projects. Features & Benefits: SuperFOIL SFTV Thermal Vapour Barrier 1.5m x 50m Roll - 75m2 If you are unclear about the building requirements, you may need to consult with other contractors in your region, or calculate your building's needs according to criteria laid out by established professional organizations. For example, the National Roofing Contractors Association (NRCA) recommends vapour barriers on the interior side of a roof in any climate where the outside average January temperature is below 40 F (4 C) degrees and the expected interior winter relative humidity is 45 percent or greater. What does a vapour barrier do?

The JSESSIONID cookie is used by New Relic to store a session identifier so that New Relic can monitor session counts for an application. Water vapour is water in its gaseous state (instead of as a liquid or solid) and is totally invisible. Water vapour constantly diffuses through building materials from the warm, humid interior of a house toward the cold, dry exterior. As water vapour passes through a wall, ceiling or other barrier and meets a surface that has a temperature below the dew point (when water vapour condenses), then it becomes condensation – and a threat to the integrity of your building materials. (Sources: Ecohome.)Further thermal efficiency can be obtained using Protect VC Foil Ultra in conjunction with breather membranes Protect TF200 Thermo and Protect TF InterFoil. Materials such as rigid foam insulation, reinforced plastics, aluminium and stainless steel can also be used as they are relatively water resistant but should also be sealed at the joints. A vapor retarder and an air barrier serve to reduce this problem, but are not necessarily interchangeable.

Zone 4 (marine) requires a Class III (or lower) vapor retarder on the interior surface of insulation in insulated wall and floor assemblies where the permeance of the exterior sheathing is 0.1 perm or less as tested by Test Method B (the “wet cup” method) of ASTM E-96) and the interior surface of the exterior sheathing shall be maintained above the dew point temperature of the interior air. Under this design approach assume steady state heat transfer, interior air at a temperature of 70 degrees F (21 degrees C), at a relative humidity specified in Table 1 and exterior air at a temperature that is equal to the average outdoor temperature for the location during the coldest three months of the year (e.g. December, January and February). In the event you are erecting a "cold building" (such as a refrigeration building) that stays at 32 F (0 C) degrees or less inside, you will need a vapour barrier on the outside of the insultation to prevent warm exterior air from entering and potentially damaging the roof’s insulation. (Source: NRCA.) Public swimming pools, saunas and other wet areas are usually sealed with aluminium foil. But aluminium foil should also be used in the insulation of house roofs. A vapour barrier plays an important role here. It ensures that moist air does not enter An interior vapor retarder is useful in heating-dominated climates while an exterior vapor retarder is useful in cooling-dominated climates. In most climates it is often better to have a vapor-open building assembly, meaning that walls and roofs should be designed to dry: [6] either to the inside, the outside, or both, so the ventilation of water vapor should be taken into consideration.Zone 5 requires a Class III (or lower) vapor retarder on the interior surface of insulation in insulated wall and floor assemblies where the permeance of the exterior sheathing is greater than 1.0 perm as tested by Test Method B (the “wet cup” method) of ASTM E-96). The College of New Caledonia (CNC) in Prince George, B.C., and Twin Maple Group have been collaborating to research the use of the aluminum reflective foil insulation as replacement for vapour barrier in wall building systems. The objective was to quantify the potential energy savings as a result of reducing radiant heat losses. (This research would not have been possible without the support from Natural Sciences and Engineering Research Council of Canada [NSERC] through an Engage Grant for Colleges. This author would also like to express thanks to Twin Maple for its in-kind contribution to this project, with respect to materials and technical expertise. CNC departments participating in the study include the School of Trades & Technology, International Education, Facilities Services, and Applied Research and Innovation.) Applicability – Limited to mixed-humid, hot-humid, mixed-dry, hot-dry and marine regions – should not be used in cold, very cold, and subarctic/arctic regions Advanced Polyethylene vapor retarders that pass the ASTM E 1745 standard tests ≤0.3USperm (17SIperm). Water can come in several phases: liquid, solid, vapor and adsorbed. The liquid phase as rain and ground water has driven everyone crazy for hundreds of years but can be readily understood - drain everything and remember the humble flashing. The solid phase also drives everyone crazy when we have to shovel it or melt it, but at least most professionals understand the related building problems (ice damming, frost heave, freeze-thaw damage). But the vapor phase is in a class of craziness all by itself. We will conveniently ignore the adsorbed phase and leave it for someone else to deal with. Note that adsorbed water is different than absorbed water (see Kumaran, Mitalas & Bomberg, 1994).