Will A Roof Leak Travel With Open Or Closed Foam

Chemical manufacturer s claim if a roof leaks water will migrate through the foam structure therefore not trapping the water.

Will a roof leak travel with open or closed foam.

Hi we recently moved into a new house. The roof is covered in expanding foam. Open cell foams will tend to leak closer to the point of entry making leaks easier to identify and locate. As with all construction products installation is critical to the performance of the product.

It is better to only use what it takes to stop the leak the flashing needs to move around the pipe for snow loads if you have. If the neoprene of the vent flashing is the only thing deteriorated filling up the gap with foam will not cause pooling any place it should not take a lot of closed cell foam to remedy the problem for the short term. Closed cell foam with higher densities and a higher r value can be an effective vapor retarder. The roof was made of 15 32 plywood 3 4 foam board and 1 4 hard board all glued and screwed together.

The camper is all closed in other then reinstalling the windows and outside trim. Once that was done i rolled out contact glue on the roof and the aluminum roof cover. Common sense tell s me if this is valid marketing then what stops water vapor from moving through the foam under pressure. From then it was screwed glued down back on to the headers.

Open cell foams use water as a blowing agent. Open and closed cell foam insulation use a blowing agent to forms the cells within it. Note that not all open cell spray foam insulations have the exact same physical properties as some are able to absorb a significant amount of water which could aggravate moisture conditions in an attic. We have identified that the roof is leaking in several places.

And this robert riversong points out could be the source of the problem. Open cell foam is just that open cell. Open cell foam is not a vapor barrier. Closed cell foams use enovate also known as 245fa.

But not open cell foam it has a perm rating as high as 35 per inch according to a technical bulletin from fomo products inc. Closed celled foams will perform better in terms of deflecting water away from interior elements but may allow leaks to go undetected longer.