If your attic needs insulation, the two materials homeowners in Toronto and the GTA compare most are blown-in insulation and spray foam. Both work, but they solve slightly different problems — and the price difference is significant.
Blown-in insulation: the standard choice
Blown-in insulation (cellulose or fiberglass) is machine-applied loose material that fills the attic floor to a consistent depth. It's the most common attic insulation in the GTA because it's fast to install, works well for topping up existing insulation, and covers irregular spaces — around wiring, pipes and framing — without the gaps that batts can leave.
It doesn't stop air leaks on its own, though. If your attic has gaps around pot lights, the attic hatch or plumbing stacks, those need to be air-sealed separately before blown-in insulation is added, or the insulation won't perform as well as its R-value suggests.
Spray foam: air sealing and insulation in one step
Spray foam expands on contact and hardens, which means it insulates and air-seals at the same time — no separate air-sealing step needed. It also achieves a higher R-value per inch than blown-in material, which matters in tight spaces like cathedral ceilings or shallow roof assemblies where there isn't much depth to work with.
The trade-off is cost: spray foam typically runs several times more per square foot than blown-in insulation. It's the right call for specific problem areas — rim joists, additions, low-clearance spaces — more often than it makes sense for an entire standard attic.
Cost and where each one makes sense
For a typical attic top-up or full re-insulation with enough clearance, blown-in insulation usually delivers the best value: lower material and labour cost for a comparable finished R-value once air sealing is done properly. Spray foam earns its higher cost in spaces where air sealing is the real problem, where headroom is limited, or where moisture control is a specific concern, like a finished attic knee wall.
Many attics actually benefit from a combination — targeted spray foam or caulking at known leak points (the attic hatch, pot lights, plumbing stacks), topped with blown-in insulation across the rest of the attic floor. That combination usually costs less than spray-foaming the whole attic and performs just as well.
The right answer depends on your attic's specific construction, current insulation and air-leak points — which is exactly what we check during a free estimate before recommending anything. Some rebate programs also apply differently depending on the material used (see our current Ontario rebates), so it's worth confirming eligibility before deciding.