Hello Pros.

I have been reading up on the use of closed-cell foam applied to brick (foundation) walls.

I live and do business in northern Virginia, where we have a heating dominated climate with hot and humid summers.

I had no concerns spraying foundation walls of basements and crawl spaces with closed-cell foam (typically 2") until I was asked about whether brick walls can actually be compromised by spraying them with closed-cell foam.

I understand building science, and therefore why I have become a huge proponent of closed-cell over open-cell foam.

So, if I spray 2" to the brick walls in a crawl space in Washington DC am I doing the right thing, or am I introducing a structural issue? I was going to spray the brick walls of a tight crawl space, as well as the rim\band joist areas, after laying down a 12 mil vapor barrier (sealing the seams and running the vapor barrier up the walls a few inches).

Thanks in advance.

Patrick

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Check out http://www.buildingscience.com/documents/insights/bsi-011-capillari... & they did have one other on spalling for spraying above grade walls. If worried maybe consider using Delta Dry on walls & then spraying???

6 to 8 inches as I recall is minimum not just a few inches

Thanks Sean.

Here in central Vermont, we see houses from the 1800s with brick walls as part of the foundation, but the brick is not structural. Large slabs of granite are holding up the typical 8x8 sill beam. If we were to spray SPF (Spray Polyurethane Foam) on the brick, we are usually not air sealing, due to the large cavity between the granite and brick. In the rare house where there is only brick (typically a double-wythe wall) supporting the sill beam, the brick is in poor condition from being subjected to high moisture from the basement or crawl space, as well as moisture from the exterior weather. In my opinion, if it is structural brick, and if it has been subjected to a chronically damp crawl space, then the brick is not drying to the interior anyway, so I would be less concerned about SPF on the interior IF the brick is in good condition. A minimum of 2" of closed cell SPF would meet the requirements for the DC area. Much more than that would be a waste, unless you are going to also insulate the floor of the crawl space. 

Thank you Brad, that is very helpful.

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