Insulation cost
How much does attic insulation cost?
The short answer
The price depends on your attic: its size, what’s already in it, and what has to be fixed before insulating. Two houses of the same size can need very different work.
That’s why we don’t publish prices here. Isolation Cornerstone gives you one in writing, after a free visit.
Floor area, current insulation, vermiculite, ventilation: what drives the price of attic insulation, and 4 questions to see whether LogisVert applies to your home.
What drives the price
Floor area
That’s the starting point. The more square feet to cover, the more insulation and time it takes.
The insulation already there
Old insulation that has settled or is unevenly spread no longer gives the R-value it had at the start. Depending on what we find, we top it up or redo the insulation completely.
Vermiculite
Granules in the attic instead of a blanket of insulation? It may be vermiculite, which can contain asbestos. It has to be removed safely before insulating, and that removal adds to the work.
Mold
Black stains on the roof deck call for decontamination. Whatever caused them has to be fixed too, so the mold doesn’t come back under the new layer.
Ventilation
A baffle at every soffit, a hatch to insulate with weatherstripping, bathroom, range hood or dryer fans to vent outside instead of into the attic. Each fix has a cost. Each one also keeps a problem from hiding under the insulation.
Access
A narrow hatch, a low or cluttered attic, and the work takes longer. The height also decides how deep we can go: R‑51 minimum with us, up to R‑60 when the attic allows it.
Caulking
If you’re aiming for the LogisVert rebate, caulking is part of the project: windows, doors, hatch, range hood, bathroom fans, outlets, fireplace. More openings means more work.
Why we go up before giving a price
What drives up the cost of an attic job is rarely visible from below. At the visit, we go up, measure the depth of the insulation, then look at the ventilation, the roof boards and the ducts. You then get a written quote.
A price thrown out over the phone, without that information, could change along the way. We’d rather give you just one.
The visit and the quote are free. No pressure, even if you choose another contractor.
Does LogisVert apply to your home?
Four questions. They follow the basic conditions in Hydro-Québec’s guide, under the rules in force on September 15, 2026. The result gives you an idea; it doesn’t replace Hydro-Québec’s decision.
FAQ
What people ask us about price
Another question? Call us at (438) 544-6512
Hi! Pick a question and we’ll answer right here.
Choose a question
- Can you at least give me a ballpark?
- Not without seeing the attic. A range pulled out of thin air wouldn’t do you any good, and the visit costs you nothing.
- Is the quote really free?
- Yes, both the visit and the written quote. Isolation Cornerstone doesn’t charge you anything to come and look, and you’re not obliged to sign afterwards.
- Is the cleanup extra?
- No, it’s part of the work. The house is protected with tarps and shoe covers, and we clean up at the end.
A price for your own attic
Leave us your details: we’ll call you back to book the visit.
Or call us at (438) 544-6512