Best Insulation Contractors near Cornwall, ON
1 of these contractors is based in Cornwall; the others serve Cornwall from towns including Alexandria (21 km), Lunenburg (12 km) and Apple Hill (24 km).
1 open weekends · 6 rated 4.5+ · 1 shows a licence
Data verified October 17, 2026
Spray-Tech Insulation
“All staff members were very professional and friendly, not to mention very accommodating to the job and my own schedule as we had to reschedule multiple times due to issues with weather and area that required spraying.”
North Country Insulation Spray Foam
“A fraction of the cost and hassle of re pouring the floor!”
Enviro-Tec Insulation
“They even squeezed me in before the holidays - much appreciated!”
Tucker Construction Inc.
“The timeline was respected, impeccable quality, price as per quotation even though they did extras without charging us”
Decoste Construction Inc.
“Easy to deal with and received updates on a regular basis and when requested.”
The 10 contractors listed for Cornwall, ON insulate attics, basements, headers and crawl spaces. Details under each one about materials, hours and advertised services are copied from the company's own site; star ratings and comments come from public reviews.
Area overview: Cornwall, ON
9 of the 10 contractors on this page have a rating, from 4.0 to 5.0 across 70 reviews; 6 are rated 4.5 or higher. 1 is open on weekends. 1 shows a licence on its website. Domain records put 4 websites of the contractors on this page at ten or more years old; the oldest dates from 2003. 5 give free estimates and 3 are family- or locally-owned. We have a website on file for 9 of the contractors on this page; 6 publish a contact page and 7 list a public email. We count these figures across the contractors on this page; distances are straight-line, and hours and prices change, so confirm the details with the contractor before you book.
Will anyone assess the house at no charge?
No charge assessments are advertised by 5 of the 10 contractors on this page. Treat that as a sales visit with a tape measure. A paid energy evaluation is the thorough version, and in some provinces it is also the paperwork that opens the door to a rebate program.
Kluke's Roofing
“The crew worked hard, were polite and cleaned up every night before leaving, James and his crew are very professional.”
Merkley Energy Solutions
“Worked with me to gain access to all parts requiring insulation with minimal deconstruction and the installers were amazingly.”
Isolation Future
Isolation Sud-Ouest
“Great service, competitive price and really clean work!!”
Why these companies made our list
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