Building your dream home here in God’s Country? Plan for our cold deep-freeze winters with a bit of extra insurance.
Under Slab Spray Foam Insulation
A good insulation package is a must in our climate, and we’re always looking for sensible, practical applications for spray foam. Insulating under foundation and basement slabs using SPF (spray polyurethane foam) offers certain advantages over the more common method of using rigid foam board.
Insulating under concrete using spray foam will control heat loss through the floor, also provide a warmer, more comfortable floor on which to walk and live.
Basements that are built on insulated concrete slabs will be more comfortable to occupy for extended periods of time, making it easier to use the floor area for bedrooms, kitchens, even whole separate suites.
A poorly insulated foundation can result in a large heat loss from an otherwise tightly sealed, well-insulated house. Foundation insulation can result in lower heating requirements, and also helps in avoiding water vapor condensation problems.
A poorly designed foundation insulation system can cause many problems such as radon infiltration, moisture problems, and insect infestation.
Closed-cell polyurethane provides a vapor barrier and good R-value in a single application. Going on much faster than foam board with a superior seamless application.
BENEFITS OF SPRAY FOAM
- Cost effective
- New building code states that if you have radiant in floor heating you must have a minimum of R5 under slab
- Custom installation is only a few hours
- Irregular shapes and areas are a breeze for spray foam
- Able to tie under slab foam to basement walls creating a continuous seal under and around the basement
- Can walk, wheelbarrow, install concrete or hydronic heating tubes same day as installing foam
- Spray foam is a vapour barrier as well as insulation so you can use 20mpa concrete instead or 25mpa Spray foam will not crack or shift when walking on or working on top
- Spray foam helps eliminate Radon Gas
Why SPF? In cold climates, insulating under a concrete floor is just common sense. But it’s fair to ask why SPF should be used instead of rigid foam board. Perhaps the greatest advantage SPF offers is that it provides a monolithic layer of insulation, with no seams or other imperfections in the thermal barrier. Because it bonds aggressively and completely to just about anything it contacts, the foam creates a superior vapor barrier around plumbing and other slab penetrations.
Cost comparison. The material cost for spray foam is higher, but once the labor to properly detail rigid foam board is taken into account, the installed price becomes competitive.
Detailing foam board to provide an equally tight barrier takes time and great care. Getting the substrate sufficiently smooth and flat to evenly support the board takes a lot of effort too. SPF, by contrast, is totally forgiving of irregularities in the substrate. And as soon as the SPF cures — within 15 minutes — it can be walked on without concern for punching through into a concealed void. There’s also far less waste involved with SPF; there are no off-cuts or other discards. We can spray the exact amount required. “Extra” foam goes to the next job instead of into the dumpster.
