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Insulated attic: blown-in fibre, even between the roof trusses

Attic insulation · Greater Montreal

Cold bedrooms, rising bills?We insulate your attic once and for all.

5.0 on Google · 48 reviews

Services

What we do in your attic

Attic insulation

Fiberglass is blown to R‑51 minimum, and up to R‑60 when the attic is tall enough. Before that, we seal the air leaks in the ceiling.

  • Attic mold removal

    White or black stains on the roof deck? We clean and treat the framing, then fix what made the mold grow.

  • Vermiculite removal

    It may contain asbestos. We assess it, remove it before insulating, then reinsulate to R‑51.

  • Attic ventilation

    The wood blocking the soffits comes out, then a baffle keeps the air intake open. The bathroom fan, range hood and dryer are vented outside, never into the attic.

  • Window and door caulking

    Windows, doors, attic hatch, range hood, outlets and fireplace: the caulking LogisVert asks for, done by the crew that insulates your attic.

The method

What we fix before the insulation goes in

Adding insulation on top of a poorly ventilated attic hides the problem instead of fixing it. We fix the air and the moisture first, then we insulate.

R‑51 minimum
  • Ceiling air leaks sealed

    Around light fixtures, wires and ducts: warm air from the house no longer rises into the attic.

  • A baffle at every soffit

    Air comes in at the eaves and flows under the roof deck, even once the insulation is in.

  • Clearances respected

    Around the chimney, light fixtures and ducts, the insulation keeps its distance.

  • Fans vented outside

    Bathroom, range hood and dryer: moist air leaves the house instead of emptying into the attic.

  • An insulated hatch, weatherstripped

    The attic door is insulated and sealed like the rest of the ceiling.

  • R‑51, from wall to wall

    The fiberglass is blown level. Depth rulers show the height reached.

Before and after

Attics before and after, in photos

The same kind of attic after: blown-in fiberglass in an even layer.Attic before the work: old batt insulation, thin and uneven. (reconstructed image)

Fiberglass blown level.

After: job-site photo from the Isolation Cornerstone Google profile. Before: reconstructed from that photo.

Google reviews

48 reviews, all five stars

Rating read on the Google profile on November 11, 2026.

Read the 48 reviews on Google

Timothé, in an Isolation Cornerstone hoodie, in front of a house.

Timothé Courval

6+ years of experience in insulation.

  • 5 stars out of 5

    “Excellent service, highly professional. A world of difference in the house since Timothée and his colleague's intervention. I highly recommend them!”

    Marie-Claude M.February 2025Translated by Google
  • 5 stars out of 5

    “Mickaël and Benjamin, 5 stars! A very professional team, so I am extremely satisfied with their services. Respectful, courteous, honest, good communication, and they left the place clean. Highly qualified, and I highly recommend them without hesitation.”

    Joanne B.June 2025Translated by Google
  • 5 stars out of 5

    “Excellent service and insulation. The team is competent, quick, and attentive. Meticulous work and remarkable results. I highly recommend them!”

    Christian R.January 2025Translated by Google
  • 5 stars out of 5

    “Best insulation company in Quebec! #1 customer service, simple and effective support and communication! Always attentive and ready to answer our questions!!! […]”

    Erick L.December 2024Translated by Google
Brick and siding house in the winter evening, an even layer of snow across the whole roof and no icicles at the edge.

The winter after

The snow stays on the roof

When the heat of the house no longer escapes through the attic, the snow stops melting from below: no icicles at the edge of the roof, no ice dams.

Rebate

LogisVert, in four conditions

Hydro-Québec decides who qualifies.

Electric
A house heated mainly by electricity.
R‑50
Minimum required, over the whole roof. We insulate to R‑51.
Caulking
Complete, from the windows to the fireplace.
9 months
To apply online, after the work.

Service area

Montreal, Laval and nearby

We come to your home to see the attic before we give you a quote. The quote is free.

  • Montreal
  • Laval
  • Lanaudière
  • Laurentides
  • Montérégie
Our office6319, rue Lacordaire, Montréal (Québec) H1T 2J9Monday to Friday, 8 a.m. to 7 p.m.Saturday, 9 a.m. to 2 p.m.Sunday, closed

See the service area

FAQ

The questions we get the most

Another question? Call us at (438) 544-6512

Isolation CornerstoneAnswers from the team

Hi! Pick a question and we’ll answer right here.

Choose a question

How much does attic insulation cost?
The price depends on the size of the attic, the insulation already there and the problems to fix. That is why Isolation Cornerstone starts with a visit, and the quote is free.
Why not just add insulation on top?
Because if the ventilation is blocked, or there are air leaks or moisture, the added insulation hides the problem instead of fixing it. The damage goes on underneath, and everything has to be redone later. Isolation Cornerstone fixes the air and the moisture first.
What R-value should I aim for?
At least R‑50 for LogisVert. At Isolation Cornerstone, we insulate to R‑51 minimum, and up to R‑60 when the attic is tall enough.
I have vermiculite. Is it dangerous?
Vermiculite may contain asbestos. Don’t move it and don’t work in the attic. Isolation Cornerstone removes it safely before the attic is insulated.
Do I qualify for LogisVert?
Maybe. You need a house heated mainly by electricity, a roof insulated to R‑50 minimum and complete caulking. Hydro-Québec decides; we check the conditions with you during the quote.
Will you pressure me?
No. You get all the information and you decide at your own pace, even if you choose another contractor. That is how Isolation Cornerstone works.

Get your free quote

Or call us at (438) 544-6512

Step 1 of 5

What work are you interested in?

Pick the main one. We’ll talk about the rest at the visit.