Basement Spray Foam Insulation Alberta

Why studs-and-batt against concrete goes wrong

The traditional Alberta basement finish is a stud wall against the foundation, fibreglass batt between the studs, poly on the warm side. It is cheap and it fails in a predictable way.

Concrete is never dry. It wicks moisture from the soil continuously, and it is cold. Warm, humid interior air reaches the cold concrete through the batt, condenses on it, and then sits between the poly and the wall with no way to dry in either direction. The batt gets damp, the studs get damp, and eventually you have mould behind a finished wall where nobody can see it.

The batt does not stop this. Fibreglass does not stop air movement, and air movement is the mechanism.

What closed-cell does differently

Closed-cell sprayed directly onto the foundation wall changes the physics. It bonds to the concrete, so there is no gap for air to circulate in. It is its own vapour retarder, so interior humidity never reaches the cold surface. And it raises the temperature of the surface behind the finished wall above the dew point.

There is no cavity for condensation to form in because the insulation is bonded to the cold surface itself.

The assembly, in order

1. Fix the water first. Foam is not a waterproofing system. Active leaks, negative grade, failed weeping tile and downspouts discharging against the wall get dealt with before anything is sprayed. Any installer who skips this conversation is setting up a problem behind a wall.
2. Closed-cell to the foundation wall, typically two to three inches, continuous, up to the rim joist and across it - the rim joist is the biggest single leak in most Alberta houses. See rim joist insulation.
3. Stud wall in front of the foam, not against the concrete, for services and drywall.
4. No poly. Adding a second vapour retarder on the warm side of an assembly that already has one traps moisture between them.

Basement development and the code

Most basement foam in Alberta happens as part of a basement development, which means permits and inspections. Exposed foam plastic requires a thermal barrier - usually drywall - under the building code, and the assembly needs to be one the inspector recognises.

We will document the assembly used for your permit.

Basement Spray Foam Insulation Alberta: Common Questions

Will it stop my basement from smelling damp? If the smell comes from humidity condensing on cold concrete, yes - that is exactly the mechanism it removes. If it comes from standing water, a floor drain or a sump, insulation will not touch it. Diagnose first.

Do I need to remove my existing framed and batted wall? To do it properly, yes. Foam has to bond to the foundation, which means getting to the foundation. Leaving damp batt in place behind new insulation is the failure mode being avoided.

How thick? Two to three inches of closed-cell covers most Alberta basements, driven by target R and by how the space will be used. See spray foam insulation cost for how the pricing works.

What about the floor? A concrete slab on grade loses less than the walls and costs more to address. It moves up the list where the basement is a living space and the cold floor is the actual complaint.

Get Basement Spray Foam Insulation Alberta Quoted

Get a free quote with the foundation type, the basement's current state and whether you are developing it. See crawl spaces and residential.