Exterior walls, additions and gut jobs
Spray Foam Wall Insulation in Guelph
Super Sprayers sprays exterior walls in renovations, additions and gutted rooms across Guelph, Cambridge, Kitchener and the towns in between. Since 2018 we have completed more than 800 insulation jobs, and the walls we are proudest of are the ones in older houses where the owner took the drywall off and decided to do it properly. Open walls are the one moment you can fix a room's insulation completely, and they don't come around often.
Many Guelph homes built before the 1980s have 2x4 exterior walls with thin or slumped batts, no real air barrier and gaps around every window. Closed cell spray foam gets far more R-value out of that shallow cavity than batts can, and it seals the top plates, outlets and window rough openings in the same pass. The difference in comfort is immediate, especially in north-facing rooms and corner bedrooms that used to feel drafty all winter.
If your walls are still closed, this page will point you to the right option, because spray foam needs open framing. Our installers are CUFCA certified, WSIB covered and work to the CAN/ULC-S705 installation standard, and we trim every wall flush with the studs so your drywaller can start the next morning.
- In business since 2018
- 800+ jobs completed
- WSIB covered, licensed and insured
- 2-year labour warranty
- 5-star Google rating
Open Walls: Renovations, Additions and Gut Jobs
When the drywall or plaster is off, we can spray every exterior wall in the room, seal the sill and top plates and fill the awkward spaces around windows, beams and corners. Kitchens, bathrooms and bedroom renovations are the most common. Additions get the same treatment, with extra care where the new wall meets the old house.
We coordinate with your contractor so the walls are open for as short a time as possible. Wiring and plumbing rough-ins should be complete before we arrive.
More R-Value From Shallow 2x4 Walls
A 2x4 wall has a 3.5 inch cavity. Here's what each option gives you in that space.
| Option | Approximate R-value | Air seal | Vapour control |
|---|---|---|---|
| Fiberglass batt | R-12 to R-14 | No | Needs poly |
| Mineral wool batt | R-14 to R-15 | No | Needs poly |
| Open cell foam | R-12 to R-13 | Yes | Needs poly |
| Closed cell foam full cavity | About R-21 | Yes | Built in |
| Flash and batt: 1.5 in closed cell plus batt | About R-15 to R-17 | Yes | Depends on design |
Flash and batt is a good middle ground when budget matters. Our batt insulation page explains how it works.
Closed Walls: Options Without Opening Up
If the walls are closed and you have no renovation planned, spray foam isn't the tool. The two proven options are injection foam, which fills empty cavities through small holes, and dense-pack cellulose, which is blown in at high density. Either one can go in from inside or outside.
See injection foam for existing walls to find out whether your walls qualify.
Thermal Bridging Through Studs
Wood studs make up a large share of a typical wall, and wood only insulates to about R-1.25 per inch. Spray foam between the studs does nothing for the studs themselves. That's why the effective R-value of a whole wall is lower than the cavity number.
The only full fix is continuous insulation on the outside, usually rigid board added when siding is replaced. If you're re-siding at the same time, it's worth planning both together.
Check the Wiring Before Any Foam Goes In
Before we spray, we look at every wire running through the wall. Modern NMD cable is fine to encapsulate in foam. Older wiring is not, and we will stop and ask you to bring in an electrician if we find it.
Knob-and-tube wiring: many pre-1950 homes near downtown Guelph and in the Old University area still have it. Insulation must never be sprayed around live knob-and-tube wiring. A licensed electrician has to assess and replace it first.
Wall Insulation Pricing Factors
Wall projects are priced on board feet, so wall area and thickness drive the number. After that, the main factors are how many windows and openings need detailed sealing, whether old insulation must be removed first, ceiling height and whether it's a single room or a whole floor. We quote each room separately so you can phase the work if you want to.
Wall Insulation Questions
Is spray foam worth it in 2x4 walls?
It's where spray foam shines. Closed cell gives about R-21 in a 2x4 cavity compared with R-12 to R-14 for batts, plus a built-in air and vapour barrier.
Can exterior walls be sprayed from inside?
Yes, as long as the drywall or plaster is removed. Almost all of our wall work is done from inside the house.
What happens to wiring and outlets when walls are sprayed?
Modern cable is safe to encapsulate, and we mask boxes and panels so they stay accessible. Knob-and-tube wiring must be replaced before any insulation goes in.
Related Services and Resources
- Injection Foam Insulate closed walls without tearing out drywall.
- Closed Cell Spray Foam The highest R-value per inch, with vapour control built in.
- Batt and Fiberglass Insulation Fiberglass and mineral wool, installed without gaps.
- Insulating Older and Stone Homes Limestone, fieldstone and century homes done safely.
- Spray Foam vs Other Insulation Foam compared with batts, blown-in and Rockwool.
Free estimate
Quote Your Wall Insulation
Send the room size, which walls are exterior and a photo of the open framing if you have one.
- Call or text226-780-8752
- Emailinfo@supersprayers.ca
- Mon to Sat: 7:00am to 9:00pmSun: 9:00am to 6:00pm