If you are finishing a basement, adding a mudroom or swapping the slab door that leads from your garage into the house, there are four or five rules in the BC Building Code that decide what that door and the wall around it have to do. Most online answers mix in American rules that do not apply here. This guide sticks to the text of the British Columbia Building Code 2024, which took effect on March 8, 2024, and points out where your city or the age of your house can change the answer.
What the garage to house door BC code actually says
The core rule is Article 9.10.13.15 of Division B. It is short enough to quote in full:
"A door between an attached or built-in garage and a dwelling unit shall be tight fitting and weather-stripped to provide an effective barrier against the passage of gas and exhaust fumes and shall be fitted with a self-closing device." A second sentence adds that "a doorway between an attached or built-in garage and a dwelling unit shall not be located in a room intended for sleeping."
Article 9.10.9.18 points back to that rule. Where a garage is attached to or built into a home, every door between the garage and the rest of the building has to conform to 9.10.13.15, and the wall and ceiling between them need an air barrier system that blocks gas and exhaust fumes.
Tight fitting and weather-stripped
The door has to close snugly in its frame, with weatherstripping on the stops so there is no open gap around the edges. The code's explanatory note says the purpose of the gas-tight barrier is to keep carbon monoxide and gasoline fumes out of the living space. A door that rattles in its frame, has torn or missing weatherstripping, or has a big gap at the bottom does not meet that intent.
A self-closing device
The door must swing shut on its own. Spring hinges or a closer arm both do the job, as long as the door actually closes and latches when you let go. A closer that has been unhooked, or a door propped open with a wedge, defeats the rule even if the hardware is there.
Never into a bedroom
The doorway cannot open into a room intended for sleeping. This matters most in renovations: turning a den or office next to the garage into a bedroom can put an existing garage door in the wrong place.
Does the door need a fire rating in BC?
For a typical house, no. Under Sentence 9.10.9.18.(3), a storage garage that serves only the dwelling unit it is attached to or built into is treated as part of that dwelling unit, so the rated fire separation is not required between the garage and the house. What the code wants instead is gas tightness: the weather-stripped, self-closing door and the air barrier.
That changes when the garage is shared or serves more than one home. For other cases, 9.10.9.18 calls for a fire separation of at least 1 h for a storage garage holding 5 vehicles or fewer, and 1.5 h for larger ones. Openings in a required fire separation then need a rated closure under Table 9.10.13.1 (for example, a 45 min closure in a 1 h separation). Houses with a secondary suite, duplexes and townhouses with shared parking also fall under the suite separation rules in 9.10.9.16. If your garage is anything other than a private garage for one home, get the answer from your building official before you buy a door.
You will often read that the door must be "20-minute rated" or "1-3/8 inch solid core." Those figures come from the U.S. International Residential Code, not from the BC Building Code's rule for a single-family garage. Do not use them as your checklist here.
The same door is also a security door
Article 9.7.5.2, "Resistance to Forced Entry for Swinging Doors," applies to swinging doors between dwelling units and attached garages. Unless the whole door, frame and hardware meet at least Grade 10 under the annex to ASTM F476, the code spells out a prescriptive package:
- Wood doors must be solid core or stile-and-rail type and not less than 45 mm thick. Stile-and-rail panels must be at least 19 mm thick and make up no more than half of the door area.
- A deadbolt with a cylinder of no fewer than 5 pins and a bolt throw of at least 25 mm, protected by a solid or hardened free-turning ring or bevelled cylinder housing.
- Hinges fastened to wood frames so that at least 2 screws per hinge go at least 30 mm into solid wood (machine screws no smaller than No. 10 on metal doors and frames).
- Deadbolt strike plates fastened with wood screws that go at least 30 mm into solid wood.
- Solid blocking on both sides at lock height between the jambs and the framing.
- If the door swings outward, hinges or pins that stop it being removed while closed.
So the 45 mm figure you may have seen is real, but in BC it comes from the forced-entry article, not from a fire rating.
The wall, the step and the alarms around the door
Air barrier in the shared wall and ceiling
The door is only one part of the barrier. Sentence 9.10.9.18.(4) requires an air barrier system conforming to Subsection 9.25.3 between the garage and the house, and where membranes are used, all joints must be sealed and supported. The explanatory note adds that care is needed wherever wiring, pipes or ducts pierce the wall or ceiling, and that if the garage is open to the attic above the house, the ceiling of the house needs the gas-tight barrier too. Pot lights, a new dryer vent or an unsealed hole for a car charger cable can all break it.
The 50 mm curb or a sloped floor
Article 9.35.2.2 deals with fumes that sit low. Where living space next to an attached garage is less than 50 mm above the garage floor, the garage floor must slope to the outdoors, or, for a garage that holds no more than 3 vehicles, an airtight curb or partition at least 50 mm high must run along the edge next to the interior space. The note explains that where there is a connecting door and the floor does not slope outward, the door has to sit at least 50 mm up or close against the curb. A ramp up to the door is allowed.
Carbon monoxide alarms
Article 9.32.4.2 applies to homes that contain a storage garage. Where a suite shares a wall or floor/ceiling with the garage, or shares an attic or crawl space with it, a CO alarm must be installed inside each bedroom or outside each bedroom within 5 m of the bedroom door. Alarms must conform to CSA 6.19, and a hard-wired alarm cannot have a disconnect switch between it and the breaker.
Garage to house door BC code checklist
Run through this garage to house door BC code list before you buy a door, finish a wall or call for an inspection. It is a summary of the articles above, not a substitute for them.
| Check | What to look for | BCBC 2024 reference |
|---|---|---|
| Fit and weatherstripping | Door closes snugly; continuous weatherstrip on the stops; no open gap underneath | 9.10.13.15.(1) |
| Self-closing | Door shuts and latches on its own from fully open | 9.10.13.15.(1) |
| Location | Doorway does not open into a bedroom | 9.10.13.15.(2) |
| Fire rating | Not needed for a garage serving only your home; check if shared or suite | 9.10.9.18.(3), Table 9.10.13.1 |
| Door construction | Solid core or stile-and-rail wood, at least 45 mm, or Grade 10 ASTM F476 assembly | 9.7.5.2.(2)-(3) |
| Deadbolt | 5-pin cylinder, 25 mm throw, protected cylinder | 9.7.5.2.(4) |
| Hinges and strike | Screws at least 30 mm into solid wood; blocking at lock height | 9.7.5.2.(6), (7), (9) |
| Shared wall and ceiling | Continuous, sealed air barrier; penetrations sealed | 9.10.9.18.(4)-(5) |
| Floor at the door | Floor slopes out, or 50 mm curb with door raised or closing against it | 9.35.2.2 |
| CO alarms | In or within 5 m of each bedroom in a suite next to the garage | 9.32.4.2.(6) |
Vancouver, other cities and older houses
The City of Vancouver does not use the BC Building Code directly. It has its own Vancouver Building By-law; the 2025 edition generally took effect on September 15, 2025 and is based on the 2024 BC Building Code with Vancouver-specific changes. We have not confirmed the by-law's exact wording for garage doors, so if your house is inside City of Vancouver limits, check the by-law or ask the City's building department. Burnaby, Richmond, Surrey and the rest of the Lower Mainland follow the provincial code, though each municipality runs its own permits and inspections.
Age matters too. The provincial order that brought in the 2024 code says work applied for under a permit before March 8, 2024 carries on under the 2018 code. In practice, the rules you are held to are generally the ones in force when the permit was issued, and a renovation that needs a permit will be inspected against the current code. If you are buying an older house and the door from the garage has no closer or no weatherstripping, it is a cheap fix worth making regardless of what was legal when it was built.
Where the overhead garage door fits in
The big overhead door is not the door this article is about. The code's gas-tight rules sit on the wall between the garage and your home. Still, the two work together. A garage with a worn bottom seal and gaps at the jambs lets in rain and cold air, which is why people start thinking about the house door in the first place. If you are insulating or heating the garage, read our notes on whether an insulated garage door is worth it in BC, and keep the car outside while it idles no matter how well either door seals.
If you live in a strata townhouse, the garage door and the door into your unit may be common property or limited common property. Our guide on who pays for strata garage door repairs in BC explains how to check before you change anything. For the overhead door itself, see our garage door repair and new garage door installation pages, or the homeowner maintenance checklist for the seals and hardware worth checking each year.
Up and Down Garage Doors works on residential and commercial overhead doors across Vancouver and the Lower Mainland, and our staff also speak Mandarin and Cantonese. Call (778) 873-7282. New clients: 10% off labour on your first repair, mention NEW10 when you book (one per household/business, work booked by Dec 31, 2026).