Garage Floor Replacement in Ottawa: What the Code Expects
Only one published price for a new garage floor, so no range
This page lists the Building Code rules a new garage slab must meet and the questions that decide the quote.
Reviewed 2026-09-30 · how we set these ranges
Garage floors fail in a few recognisable ways. Pick yours to see what to have checked and which quotes to ask for. A new garage slab has clearer Code rules than any patio, and they belong in the written specification.
What are you seeing?
-
Cracked garage floor
- What the sources say
- Fill that changes volume when it freezes must not be used under a floor that will freeze.
- Have a contractor check
- Whether the cracks move with the seasons, and what fill is under the slab.
- Repair routes to ask about
- Crack sealing, partial or full replacement.
- When replacement comes up
- Ask the City before the old floor comes out; we found no City statement on a permit for replacing it.
- Published price
- Too few published prices for garage floors.
-
Floor drains toward the house
- What the sources say
- The Code requires an attached garage floor to slope to drain liquids to the outdoors.
- Have a contractor check
- The current slope and where water collects.
- Repair routes to ask about
- Replacement or partial replacement with a corrected slope.
- When replacement comes up
- Ask for the planned slope in writing.
- Published price
- Too few published prices for garage floors.
-
Soft, dusty or worn surface
- What the sources say
- The Code says dry cement shall not be added to a floor surface to absorb surplus water.
- Have a contractor check
- Whether the slab is sound under the surface.
- Repair routes to ask about
- Resurfacing if the slab is sound, or replacement. Coatings such as epoxy are a different trade.
- When replacement comes up
- If the slab is moving or cracked through, an overlay will not fix it.
- Published price
- Too few published prices.
Not a diagnosis: a contractor has to see the concrete. Every number above is a published figure or a City or Code rule.
The rules behind this job
Garage floors need at least 32 MPa at 28 days and a water-to-cement ratio no higher than 0.45. A floor slab is at least 75 mm thick, and the 100 mm granular layer need not be installed under garage slabs.
O. Reg. 163/24, Div. B, 9.3.1.6, 9.3.1.7, 9.16.4.3, 9.16.2.1An attached garage floor slopes to drain liquids to the outdoors, and a construction joint is provided between the house slab and the garage slab.
O. Reg. 163/24, Div. B, 9.35.2.2 and 9.35.3.2When the air is below 5 °C, the Code requires concrete to be kept between 10 °C and 25 °C while mixed and placed, and at not less than 10 °C for 72 hours after placing; no frozen material or ice may be used.
O. Reg. 163/24, Div. B, 9.3.1.9The City of Ottawa hardscaping licence covers hard landscaping features such as concrete pads, steps, walkways and patios; we found no City statement that it covers a floor inside a garage, so ask whether it applies.
City of Ottawa, Hardscaping Contractor Licence
Ask before you sign
- What thickness, strength and slope will the new slab have, in writing?
- What fill goes under it?
- Will you ask the City about a permit before the old floor comes out?
More on this work: Garage Floor Slabs
Concrete Pro IQ answers behind this page
- Sunken garage floor in Riverside South: who do I call?
- Who should break out an old garage floor in Gloucester?
- My Stittsville garage floor slopes toward the house: what now?
- What concrete strength does Ontario's Code set for a garage floor?
- What is the strength rule for Ontario garage floors versus patios?
Quick answers
Do I need a permit to replace a garage floor?
We found no City of Ottawa statement on it. The City lists structural repairs among permit projects, and a slab that carries walls is designed under Part 4, so ask the City's Building Code Services first.
Want this done at your place?
Tell us about your concrete job and we'll send it to local Ottawa concrete contractors, who reply by email. We send it out to local contractors for you. Free, no pressure.