Spray-on housewrap
Robert Martin| Posted inEnergy Efficiency and Durabilityon
My contractor asked me to look into doing a spray-on housewrap instead of a normal wrap.
He said I could cut down on using insulated siding and in-house spray-in foam. I like the idea of the spray-on housewrap but not sure about its effect versus spray foam inside.
Any insight one way or the other on this subject. This is new construction.
Thanks,
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Replies
Robert,
This type of product is usually called a liquid-applied WRB. (A WRB is a water-resistive barrier.)
The purpose of a WRB is to act as a barrier to wind-driven rain that gets past the siding. It protects the wall sheathing from rot.
On the other hand, spray foam insulation has a different purpose. It is usually used as insulation (to provide R-value) or to reduce air leaks.
It's true that a liquid-applied WRB is also useful at reducing air leakage, so in a sense there is some overlap between a liquid-applied WRB and spray foam. (If you made a Venn diagram, the area where the two circles overlap would be labeled "helps reduce air leakage.")
For more information on liquid-applied WRBs, seeHousewrap in a Can: Liquid-Applied WRBs.