Bonus rooms, cantilevers and bump-outs
Floor Over Garage Insulation and Spray Foam Between Floors in Guelph
Super Sprayers fixes cold floors over garages, cantilevers, porches and bump-outs in homes across Guelph, Milton, Kitchener and Waterloo. Since 2018 we have completed more than 800 insulation jobs, and the bonus room over the garage is one of the complaints we hear most from owners of homes built in the last 30 years. The room has a vent and a thermostat like every other bedroom, yet it is always a few degrees colder and the floor feels like tile even with carpet on it.
The cause is almost always the same. The floor sits over an unheated garage, and the batts stuffed between the joists have sagged away from the subfloor, leaving a gap where cold garage air flows freely under the room. Heating ducts often run through that same cold cavity, so the air coming out of the register has already lost its heat before it arrives.
Spray foam fixes this from below, without lifting a single floorboard. We open the garage ceiling, spray closed cell foam against the underside of the subfloor and the rim, and the ceiling goes back up. Our crews are CUFCA certified, WSIB covered and follow the CAN/ULC-S705 installation standard, and the same approach works on cantilevered floors and rooms over open porches.
- In business since 2018
- 800+ jobs completed
- WSIB covered, licensed and insured
- 2-year labour warranty
- 5-star Google rating
Why Rooms Over Garages Stay Cold
Batts are installed from below, so gravity is always working against them. Within a few years they sag, and the gap they leave under the subfloor becomes a channel for garage air. The rim joist at the garage door opening is usually poorly sealed too, so outside air joins in.
Ducts running through the floor to the bonus room make things worse. Their heat escapes into the cold cavity, and the supply air reaches the room lukewarm.
Cantilevers, Bump-Outs and Bay Windows
A cantilever is a section of floor that hangs past the foundation wall, common under bay windows and upper bump-outs. Outside air gets in through gaps at the soffit and moves along the joist bays into the house. It's why the floor near a bay window feels drafty.
We usually reach cantilevers by removing the soffit panels underneath. Closed cell foam seals the joist ends and the underside of the subfloor, and the soffit goes back on.
Floors Over Porches and Unheated Spaces
Rooms built over open porches, breezeways and crawl spaces have the same exposed-floor problem. Wherever we can reach the underside, closed cell foam gives the most R-value and air sealing in the limited joist depth. The approach mirrors our crawl space insulation work.
Fixing It From Below
A typical bonus room floor takes two to three days from start to finish.
- 1
Open the ceiling
Garage ceiling drywall under the room is removed and bagged.
- 2
Pull the old batts
Sagging insulation comes out and the cavity is cleaned.
- 3
Seal ducts and edges
Duct joints and the rim at the garage door header are sealed.
- 4
Spray closed cell
Foam goes against the subfloor, rim and ducts in controlled lifts.
- 5
Close the ceiling
New drywall goes up, taped to maintain the garage separation.
Sound Between Storeys
Foam between floors inside the house, rather than over a garage, is usually about noise. Open cell foam softens voices and TV sound between levels. For footstep noise it needs help from a resilient ceiling, as explained on our soundproofing page.
Floor Insulation Questions
Can you fix a cold bonus room without lifting the floor?
Yes. We work entirely from the garage below by opening the ceiling, so the room above isn't touched.
Who replaces the garage ceiling drywall?
We can arrange the drywall as part of the job or leave it for your own contractor. Either way, the new ceiling has to maintain the fire and gas separation between the garage and the house.
Free estimate
Warm Up That Cold Room
Tell us which room is cold, what's underneath it and roughly how big it is.
- Call or text226-780-8752
- Emailinfo@supersprayers.ca
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