{"product_id":"trade-select-sarking-hvb","title":"Trade Select Sarking HVB High Vapour Barrier","description":"\u003cp\u003eTrade Select Sarking HVB is the tightest membrane Ametalin make in this range. Class 1 vapour barrier at 0.002 µg\/N·s, extra heavy duty, one size at 1350 mm x 60 m covering 81 m².\u003c\/p\u003e\n\u003ch3\u003eClass 1 is a different order of tightness\u003c\/h3\u003e\n\u003cp\u003eThe vapour classes run 1 to 4, with Class 1 the tightest barrier and Class 4 the most permeable. Most reflective sarkings sit at Class 2. HVB is Class 1, roughly twice as tight again as the standard \u003ca href=\"\/products\/trade-select-sarking-hd\"\u003eSarking HD\u003c\/a\u003e. That is what you want over a cool room, a swimming pool hall, a food processing area or any building where the inside carries far more vapour than the outside and it must not reach the structure.\u003c\/p\u003e\n\u003ch3\u003eExtra heavy duty\u003c\/h3\u003e\n\u003cp\u003eTensile strength 15.2 kN\/m machine direction against a 13.0 kN\/m minimum, edge tear 646 N against 90 N, nominal thickness 0.17 mm.\u003c\/p\u003e\n\u003ch3\u003eWhere it is the wrong choice\u003c\/h3\u003e\n\u003cp\u003eA Class 1 barrier on the outside of a wall that also has a vapour barrier on the inside traps moisture between them with no way out. HVB belongs on the warm side of the insulation, or in a roof detail designed around it. If the assembly is meant to dry outward, use a permeable membrane such as \u003ca href=\"\/products\/trade-select-vapourtech-brane-vhp\"\u003eVapourTech Brane VHP\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eOn site\u003c\/h3\u003e\n\u003cp\u003eAmetalin declare RT 0.93 winter and RT 1.51 summer for an unventilated 22 degree residential roof, and RT 2.93 winter for a brick veneer wall with an R2.7 batt. Tape every join and seal every penetration, because a Class 1 barrier with holes in it is not a Class 1 barrier. It is electrically conductive, so keep it clear of wiring. Full figures are in the table below.\u003c\/p\u003e","brand":"Ametalin","offers":[{"title":"1350 mm x 60 m (81 m²)","offer_id":45385986310326,"sku":"TSXHD-HVB-81","price":187.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0732\/3995\/3590\/files\/Sarking-HVB-Product-Shot-1024x1024-Trade-Select.jpg?v=1787844732","url":"https:\/\/awbm.com.au\/products\/trade-select-sarking-hvb","provider":"AWBM","version":"1.0","type":"link"}