Slab edge and stem wall both assessed
Slab-on-grade garages fail differently than full stem wall builds.
What garage foundation parging work includes
The same standard applies whether the garage is attached to the house or standing on its own.
Salt residue washed off before coating
Chloride left on the surface interferes with the bond.
Door strip handled properly
The band between the overhead door and the driveway gets its own treatment.
Cement or acrylic chosen per wall
Damp detached garage walls often do better under a flexible acrylic coat.
Written quote within 24 hours
Itemized by wall so you can stage the work if you want to.
Our Process
How a garage foundation parging job runs
1
Send a photo of the door strip
That short band tells us most of what we need to know.
2
Walk all four garage walls
We sound the coating and check where grade sits.
3
Written quote in 24 hours
Broken out by wall and by scope.
4
Prep, coat and finish
Salt washed off, failed material cut back, new coat applied.
Why garage foundations lose their parging first
Road salt arrives by vehicle
Brine drips off wheel wells and pools against the slab edge all winter.
Snow gets piled against it
Cleared driveway snow ends up banked on the one wall nobody inspects.
Least-maintained wall on the lot
House foundations get looked at; garage foundations usually do not until something spalls.
What garage foundation parging covers
Ottawa Parging Experts gets called about garage foundation parging after somebody finally looks down at the wall beside the overhead door and finds it crumbling, and the honest reason it got that far is that garage foundations are the least-maintained wall on most properties. People inspect the house. Nobody inspects the garage. It is behind the car, it is at ankle height, and it is grey against grey, so a coating can shed most of its face before it registers as a problem.
The work covers three distinct surfaces. On a slab-on-grade garage, it is the exposed edge of the slab and the thickened footing beneath it. On a garage built over a stem wall or a full foundation, it is the same band of exposed concrete or block you would find on the house. And on both, there is the short strip where the foundation meets the driveway under the overhead door, which behaves nothing like the rest of the wall.
Why garage foundation parging fails before the house wall does
Road salt is the difference. Every winter trip brings brine off the road in the wheel wells and under the body of the vehicle, and it drips off inside the garage and along the apron just outside the door. That chloride-laden meltwater pools against the slab edge and the door strip, soaks into whatever it can, and then goes through the same freeze-thaw cycling as everything else. Industry estimates for this market put the annual cycle count at 50 or more, and Ottawa records roughly 17 nights a year at -20°C or colder.
Salt makes each of those cycles worse. It draws moisture in, it keeps the surface wetter for longer, and it lowers the temperature at which the water in the pores freezes, so the surface can cycle through freezing more times per winter than an unsalted wall a few metres away. That is why the strip under the door is almost always the first section to lose its coating while the back wall of the same garage still looks acceptable.
Snow storage adds to it. Cleared driveway snow gets piled somewhere, and that somewhere is usually against the garage. A snowbank keeps the bottom foot of the wall saturated well past the point where the rest of the property has dried out, then dumps meltwater right at the base during every thaw. Combine that with the fact that much of the Ottawa area sits on Leda clay, a sensitive marine clay left behind by the Champlain Sea, and a garage slab that has settled slightly at one corner will show cracked parging along that line first.
Repairing garage foundation parging at the door and slab edge
The prep on a garage is different from the prep on a house wall, and skipping the difference is why some garage coatings fail twice. The wall gets washed down first to remove salt residue and the fine grit that comes with it, because chloride left in place sits between the substrate and the new material and lets the coat release early. Then the wall dries before anything gets applied.
Failed coating gets cut back to material that is genuinely bonded. We sound the surface rather than guessing, because a coat can look attached and be hollow behind. Where the slab edge itself has lost depth and aggregate is working loose, that is concrete repair, not parging, and we will say so rather than skim over it.
For material, our standard is polymer-modified, fibre-reinforced cement parging. On detached garages that sit low, drain poorly, or have had grade built up against them over the years, flexible acrylic parging is often the better answer because it tolerates a wall that stays damp and moves a little. Curing needs above-freezing temperatures, so garage work runs spring through fall within the local frost-free season, roughly late April to early October.
What garage foundation parging costs in Ottawa
Most garage jobs are small enough to sit at the lower end of our pricing. A door strip and one short section of slab edge falls in the patch repair range of $300 to $600. Two or three walls of a detached garage, or a full door-side rebuild with adjacent sections, usually lands in the moderate repair range of $600 to $1,500. A complete recoat of a larger detached garage, or a garage plus adjacent house wall done together, moves into the extensive repair range of $1,500 to $6,000. New application on bare block or concrete runs $15 to $30 per linear foot.
Estimates are free, on-site or by photo, and the written quote follows within 24 hours itemized by wall so you can stage the work across seasons if that suits you better. Done properly, a garage coat should hold roughly 10 to 25 years, though a wall that gets a snowbank against it every winter sits at the lower end of that.
If the coating is intact and only the top edge looks tired, that can wait. If the door strip is spalling and the slab edge is losing aggregate, it should not.
Garage foundation parging questions we get in Ottawa
The concrete just inside my overhead door is flaking into chips. Is parging the fix?
Sometimes, and sometimes not. If the flaking is surface spalling on sound concrete, a parge coat over prepared substrate handles it. If the slab edge has lost depth and you can see aggregate coming loose, that needs concrete repair before any coating goes on, and a parge coat alone would only hide it for a season.
Does a detached garage need the same treatment as the attached one?
The exposure is different. A detached garage usually sits lower, drains worse, and often has grade built up higher against it over the years, so the wetted band runs higher up the wall. That frequently makes flexible acrylic parging the better choice on a detached garage even when cement is right for the house.
Can I have the garage done without doing the whole house perimeter?
Yes. We quote by wall, so a garage-only job is a normal request. Where colour or texture would visibly differ from an existing house coat on an attached garage, we will point that out before you decide, because a mismatched patch on a street-facing wall is worth knowing about in advance.
Will washing the road salt off really change anything?
It changes the bond. Chloride residue and the fine grit that comes with it sit between the substrate and the new coating, and a coat applied over that lets go early. Washing down and letting the wall dry is a short step that materially affects how long the finish lasts.
My garage floor slopes toward the back wall. Does that matter for parging?
It matters a lot. Water that runs to the back of the garage instead of out the door sits against the foundation at the low corner, and that corner will keep failing no matter how well it is coated. We will flag the drainage issue when we quote rather than coat over a problem that will come back.