Calgary garages are treated as afterthoughts by most contractors. An attached garage has code requirements (Type X fire separation on shared walls), climate requirements (vapour barrier and board type depend on whether it’s heated), and durability demands from -30°C to +5°C swings every winter. Getting any of these wrong means failed inspections, callbacks, or drywall that delaminates by year three.
Alberta Building Code requires a 1-hour fire separation between an attached garage and living space — 5/8” Type X drywall on the garage side of shared walls and ceiling (if living space above). Standard 1/2” board fails inspection and voids fire insurance on claims. It’s not a technicality; it’s a fundamental assembly requirement that determines how long occupants have to exit in a fire.
Heated vs. unheated garages differ significantly in what goes behind the board. A heated garage needs a vapour barrier on the warm side of insulation before boarding — without it, moisture from the conditioned space migrates into the wall cavity and condenses on cold exterior sheathing. An unheated garage has the inverse risk: condensation forms on the board surface during cold snaps. Moisture-resistant board is the correct choice here, even without a full vapour barrier system.
Our crew scopes the full assembly before quoting — board type, vapour barrier placement, fastener pattern for inspection-ready Type X, perimeter sealing, and penetration caulking on every electrical box and pipe sleeve. You receive a written quote with materials itemized before we lift a sheet.
Board type isn’t a single decision across a garage — it changes by zone. Here’s what the Alberta Building Code and sound building science require for each area of a typical attached garage.
| Zone | Board Required | Key Requirement |
|---|---|---|
| Garage-to-house wall (attached) | 5/8” Type X | 1-hour fire separation per ABC 9.10.9.1 |
| Ceiling above garage (with living space above) | 5/8” Type X | Fire separation continues through ceiling |
| Exterior garage walls (unheated) | Moisture-resistant 1/2” | Condensation protection |
| Exterior garage walls (heated) | Standard 1/2” or better | Vapour barrier required on warm side |
| Ceiling (detached garage) | Standard 1/2” | No fire separation required |
The three most common garage drywall failures we see when called in to fix previous work. Each one requires stripping and redoing the assembly — there is no patch for a missed fire rating or a failed vapour barrier.
Using standard 1/2” drywall where Type X is required is the single most common garage drywall failure we encounter. Inspectors measure board thickness at cut edges. If you’ve had prior work done and aren’t sure what’s behind the tape, we can do a moisture check and assembly review as part of the quoting process.
Every electrical box, pipe sleeve, and HVAC duct penetrating the fire wall must be sealed with approved fire caulk. One unsealed box negates the entire assembly’s fire rating. Inspectors look specifically at penetrations because they’re the most commonly missed element — and the most important one in a real fire event.
Moisture from the heated space migrates into the wall cavity and condenses on the cold exterior sheathing. Without a vapour barrier, this causes mould inside the wall within 2–3 winters. Calgary’s dramatic temperature swings accelerate this cycle compared to milder climates. The problem is invisible until the mould has spread significantly.
A homeowner in Thorncliffe was finishing a large attached 2-car garage as a heated workshop. The scope revealed the shared house wall had standard 1/2” drywall from the original 1997 construction — never updated despite two prior renovation permits on the main house. The existing board didn’t meet the current code requirement for the 1-hour fire separation.
Our crew removed the old board, ran a moisture check on the framing behind it, installed a vapour barrier on all exterior walls (heated space requires it), re-boarded the fire wall with 5/8” Type X with correct fastener spacing and perimeter caulking, and used moisture-resistant board on all exterior walls. All penetrations were sealed with approved fire caulk before inspection. The project passed inspection on the first attempt.
Written quote with materials itemized. We confirm board type, vapour barrier, and fire separation requirements before we start.