Spray Foam Under Slab Foundation
Applying spray foam insulation before pouring a concrete slab foundation has many benefits- first, it provides durability by protecting the concrete. Second, it creates a tight seal against moisture and air infiltration, especially around protruding pipes and against foundation walls. And third, it provides an additional thermal barrier, resulting in more comfortable floor and room temperatures year-round.
While rigid foam board is traditionally used for this application, applying spray foam has several added advantages. For example, it doesn't have to be taped, it creates more airtightness, and concrete can still be easily poured over top. We recommend this application in particular for slab foundations and any foundation with radiant in-floor heat.
