Renovation Quotes in 2026: What the Building Code Should Be Covering
There's a lot of content online right now about "the 2026 Ontario Building Code."
It's worth clearing something up before anything else: the current code is the 2024 Ontario Building Code. It came into effect January 1, 2025, and since April 1, 2025 every permit application in the province has had to be designed to it.
What's different about 2026 isn't the rules, it's that the transition period is fully over, the transitional provisions have closed, and building departments are now reviewing every file against the new requirements without exception.
Which matters, because a lot of quotes homeowners are receiving were built on assumptions from the old code.
Here's what actually changed, and where it shows up in your project.
1. Radon and soil gas rough-ins
This is the change most likely to affect a homeowner directly, and the one most likely to be missing from a contractor's numbers. The 2024 Code requires new houses and additions with new foundations to include a rough-in for a subfloor depressurization system, plus measures to resist soil gas entering the building.
In plain terms, that's:
A layer of clean granular material under the slab
A capped 100 mm pipe running from beneath the slab up through the house, labelled for radon removal only
A soil gas barrier on foundation walls, poly under the slab, and sealed perimeter joints and penetrations
Rough-in does not mean an active system. No fan is required at occupancy. The point is that the house is built so mitigation can be added later without tearing up a finished basement. This is really the same logic as roughing in plumbing for a bathroom you haven't built yet.
Radon is a naturally occurring soil gas. It's present at some level everywhere in Ontario. Whether your specific home has elevated levels can only be determined by testing after you move in which is why the code asks for the rough-in rather than the fan.
What this means for you: if you're getting quotes for a custom home, an addition with a new foundation, or a garden suite, ask directly whether radon and soil gas control is shown on the permit drawings and included in the price. In Hamilton, for example, the city requires permit drawings to clearly detail the mitigation approach before a permit is issued.
2. Secondary suites and additional dwelling units (ADUs)
The 2024 Code aligned Ontario's secondary suite provisions more closely with the National Building Code, while keeping flexibility on suite sizes to support housing supply.
Layered on top of that, Bill 23 (the More Homes Built Faster Act) allows up to three residential units as-of-right on most residential lots connected to municipal services, typically the main house, an interior suite, and a detached garden suite. Garden suites under 100 square metres are generally exempt from development charges, which in many municipalities is a meaningful reduction in project cost.
What this means for you: the planning permission is easier than it was. The building requirements are not looser. Fire separation between units, sound separation, egress from every bedroom, interconnected smoke and CO alarms, ceiling heights, and ventilation all still apply and a suite that's permitted as-of-right still has to be built to code and inspected.
3. What didn't change: the inspection process, and why it still catches people
The Code requires a municipal building official to attend an inspection within two working days of being notified. That's a reasonable service standard, and it works provided the inspection actually gets booked.
The failure mode is always the same: work gets covered before sign-off. Insulation goes over a framing inspection that never happened, drywall goes over a rough-in that was never signed. The remedy is uncovering it, which is expensive and demoralizing in equal measure.
The other version of this is the permit that never gets closed. An open permit surfaces years later at sale, at refinancing, or in an insurance claim.
4. The renovation question everyone asks: does the whole house have to be brought up to code?
No — it’s the new work that must comply with the current Code. Existing construction generally doesn't have to be retroactively upgraded simply because you're renovating elsewhere in the house.
But the boundary between "new work" and "existing" is a judgment call made during permit review, and it moves depending on scope. A kitchen refresh and a whole main-floor rebuild sit in very different places on that spectrum. Where a renovation is extensive enough to touch structure, envelope, or life-safety systems, expect more of the house to be pulled into compliance and expect that scope to be established at permit review, not discovered mid-build.
This is one of the better arguments for having a designer and a builder in the same conversation early. The question "how much of this triggers a code upgrade?" has a budget attached to it, and it's much cheaper to answer in design than in demolition.
Questions worth asking any builder in 2026
Is radon and soil gas control shown on the permit drawings and included in the quoted price?
Which parts of my existing home will be pulled into current-code compliance, and what does that cost?
Who books the inspections, and at what stages?
Who is responsible for closing the permit at the end?
Planning a renovation, addition, or custom build in Oakville, Burlington or Hamilton?
Onelife Design & Build handles design, permits, and construction under one roof which means code compliance is priced into the project from the first estimate, not added to it later. Book a consultation.
