finally radiation which is the transfer of heat through electromagnetic waves when installed under a radiant surface such as a hot roof the interior surface temperature is significantly lowered which also lowers the radiant heat load open cell foam has a perm rating of around NUMBER_TOKEN for a NUMBER_TOKEN inch depth so it cannot block water vapor it needs an additional vapor barrier like a sheet of plastic to prevent condensation inside the wall closed cell foam acts like a vapor barrier when thick enough over NUMBER_TOKEN inches it has a perm rating of less than one perm for a two inch depth to test the water resistance of open cell foam i poured some water mixed with the green dye over it the liquid immediately seeped through the gaps and the open pores open cell foam is moisture permeable meaning water can move through it but its performance really depends on the brand some foam retains only five percent of its weight in water while cheaper brands retain as much as NUMBER_TOKEN percent closed cell spray foam on the other hand is NUMBER_TOKEN moisture impermeable meaning it does not allow water to move through it liquids seeped through some of the cracks when most of it just puddled on the top while closed cell foam might sound like the better option in all cases open cell foam might be better on a roof deck if a leak were to occur the foam would be discolored and it could be quickly repaired closed cell foam on the other hand would conceal the leak and water could build up somewhere else which can cause bigger problems before we move on to their surprisingly poor fire resistance i'd like to talk about the sponsor of this portion of the video insulation for u.s they are the largest u.s online retailer for insulation products they ship nationwide with over NUMBER_TOKEN locations in their huge distribution network installation for us is cheaper than big box retailers and they offer a NUMBER_TOKEN flat shipping fee on eighty percent of all products brands such as owens corning rockwell hunter panels rmax kingspan handy form spray foam bubble wrap and more are available online to purchase today and to be delivered directly to your job site use promo code belinda NUMBER_TOKEN to receive an additional NUMBER_TOKEN discount of your next order with URL_TOKEN
START_SPONSOR_TOKEN before we move on to their surprisingly poor fire resistance i'd like to talk about the sponsor of this portion of the video insulation for u.s they are the largest u.s online retailer for insulation products they ship nationwide with over NUMBER_TOKEN locations in their huge distribution network installation for us is cheaper than big box retailers and they offer a NUMBER_TOKEN flat shipping fee on eighty percent of all products brands such as owens corning rockwell hunter panels rmax kingspan handy form spray foam bubble wrap and more are available online to purchase today and to be delivered directly to your job site use promo code belinda NUMBER_TOKEN to receive an additional NUMBER_TOKEN discount of your next order with URL_TOKEN END_SPONSOR_TOKEN