Foundation parging

Parging repair in Durham Region

Parging is the cement coating on the part of your foundation you can see above ground. When it cracks and falls off it looks alarming, but it's usually a surface problem. Here's what it does, why it fails and what the repair costs.

Get matched with a contractor How it works

Free for homeowners. We match you with a vetted, independent local contractor. See how it works.

What parging is, and what it isn't

Parging is a thin layer of cement-based mortar trowelled onto the exposed part of a foundation wall, usually the strip between the soil and the siding or brick. It gives concrete block and poured walls a smooth finish, sheds rain and protects the surface from weather.

It is not waterproofing. It doesn't keep groundwater out of the basement, and replacing it won't fix a leak. If you're seeing water inside, start with leaking basement repair.

Why parging fails in Durham

Freeze-thaw: southern Ontario sees dozens of freeze-thaw cycles every winter. Water that soaks into cracked parging freezes, expands and pushes it off the wall.
Splash and runoff: downspouts, sprinklers and roof drip keep the bottom of the wall wet.
Thin, single-coat work: common on new builds and quick flips. It looks fine for a year or two.
Applied over loose material: new parging only sticks as well as whatever is under it.
Non-breathable paint: traps moisture behind the parging.

When it's more than parging: if the crack continues into the concrete behind, the wall bulges, or the basement leaks at the same spot, the parging is a symptom. Have the foundation itself looked at. See which foundation cracks matter.

Patch or re-parge?

A common guideline: if less than about a third of the wall's parging is damaged, patch the bad areas. Beyond that, a full re-parge usually lasts longer and looks better than a quilt of patches.

What good parging work looks like

All loose and hollow-sounding parging chipped off back to sound material
The wall cleaned and dampened, with a bonding agent applied
Two coats (a scratch coat, then a finish coat), not one thin layer
Kept damp and protected while it cures, and never applied in freezing weather
For old stone or brick foundations: a softer, compatible mortar, since hard cement can damage old masonry

Older homes in central Oshawa, downtown Whitby and old Bowmanville and Newcastle often have block or masonry foundations where parging does the most work, and fails most visibly.

What parging repair costs around Durham

Job	Typical cost (CAD, 2026)
Per square foot, two-coat application	$6 – $12
Small isolated repair	$300 – $900
One side of the house	$800 – $2,000
Complete re-parge, whole house	$3,500 – $7,000

Ranges from published Toronto-area price guides. They're general estimates, not quotes. See the full Durham cost guide. Local guides: Pickering · Ajax · basement waterproofing

Get matched with a contractor

Common questions

Does parging stop basement leaks?

No. Parging protects and finishes the exposed part of the foundation, but it isn't waterproofing. If water gets into your basement, the cause is below ground: a crack, the weeping tile, grading or a window well. New parging over the top won't fix it.

How long should parging last?

Done properly (loose material removed, a bonding agent, two coats, cured slowly), parging typically lasts 10–20 years in a southern Ontario climate. A single thin coat over old, loose parging often fails within two or three winters.

Can I paint my parging?

Only with a breathable masonry coating made for the purpose. Ordinary paint traps moisture in the concrete, and freeze-thaw then pops the parging off from behind. That's a common reason for flaking.

Can I parge it myself?

A small patch, yes, if you chip back to solid material, use a bonding agent and keep the patch damp while it cures. Larger areas are harder to get right, and bad parging fails fast, so most people hire a mason or foundation contractor for more than a small patch.

When is the best time to parge in Durham?

Late spring to early fall. Cement-based parging shouldn't be applied or left to cure in freezing weather, and it needs protection from hot sun and heavy rain for the first few days.

Tell us what you're seeing

Free, no obligation. We'll review your request and get back to you, then put you in touch with a vetted local foundation contractor who'll book an assessment and give you a written quote.