Is Spray Foam Good for My Crawl Space Sub-floor
Are you considering spray foaming the sub-floor of your crawl space in order to make your home more comfortable and maybe even save some money? Many contractors and DIYers are using this method but what are the risks involved with spray foam on the sub-floor?
Spray Foam Traps Moisture
If you spray foam your sub-floor and the wood moisture is high, you just trapped the moisture in the wood. Due to the sealing capability of spray foam it is very difficult to dry wood after it is applied. This goes for open cell or closed cell spray foam. Both do a great job at trapping moisture.
Spray Foam Traps Mold
Just like moisture, if mold is present when you apply the spray foam, it gets trapped as well. Spray foam does not kill or remove mold. It encapsulates the mold and moisture together so the mold still has its food source and moisture. With wood to feed on and high moisture levels, there is no remediation process once the mold is encased in spray foam without completely removing the foam.
Spray Foam is Hard to Remove from Sub-floor
In the picture above the mold and moisture are trapped behind the spray foam. One could argue the mold developed after the spray foam was applied but most likely it was used to cover the mold. Some crawl space encapsulation companies that don’t understand mold removal will cover up mold with spray foam or paint versus addressing it properly.
If you made the mistake of hiring such a contractor, your sub-floor is in big trouble. Paints and spray foams are very difficult to remove without grinding. As much as we love soda blasting, it seems to be ineffective at spray foam removal as well. Even if you took the bulk of the spray foam off, it leaves a thin plastic type seal behind. This thin seal still traps moisture and mold.
When to Use Spray Foam in Crawl Space
When Crawl Space Ninja uses spray foam in the crawl space it is to seal large holes and restrict air movement from the crawl space to the living space. We don’t like any type of insulation in the sub-floor when wall or foundation insulation can be installed and your crawl space is encapsulated. If you have a vented crawl space then sub-floor insulation is still recommended. But, I would choose batt insulation over spray foam sub-floor insulation because at least batts can be removed and replaced if necessary.
Do you need sub-floor, foundation, or attic insulation installed in your home? If so, please contact Crawl Space Ninja and we will be glad to help. Also, let us know in the comments below if you installed spray foam in your sub-floor and how did it go.
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