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Colder temperatures and building Code

It’s pretty darn obvious that the colder nights are coming. For most of us, that means nothing more than reluctantly starting up the wood stove, or setting a baseboard heater.

But for builders, cold weather means a bunch of considerations – or a stop to some kinds of construction entirely. Here’s a quick rundown on Code-enforceable temperature limits:

Concrete (9.3.1.9): When the air temperature is below 5°C, concrete shall be

  • a) kept at a temperature of not less than 10°C or more than 25°C while being mixed and placed, and
  • b) maintained at a temperature of not less than 10°C for 72 h after placing.

Mortar (9.20.14.1): Mortar and masonry shall be maintained at a temperature not below 5°C during installation and for not less than 48 h after installation.

Stucco: (9.28.6.1): 

  • 1) The base for stucco shall be maintained above freezing.
  • 2) Stucco shall be maintained at a temperature of not less than 10°C during application, and for not less than 48 h afterwards.

Drywall mud: (9.29.5.10): In cold weather, heat shall be provided to maintain a temperature not below 10°C for 48 h prior to taping and finishing and maintained for not less than 48 h thereafter.

Now, juuuuust in case you and your loved ones are arguing over what the correct indoor temperature should be, here’s what the National Building Code of Canada says: “At the outside winter design temperature, required heating facilities shall be capable of maintaining an indoor air temperature of not less than

  • a) 22°C in all living spaces,
  • b) 18°C in unfinished basements,
  • c) 18°C in common service rooms, ancillary spaces and exits in houses with a secondary suite, and
  • d) 15°C in heated crawl spaces.”