How much does subfloor replacement cost in Calgary?

Subfloor replacement in Calgary typically costs between $4 and $8 per square foot for materials and labour, with most full-home projects landing in the $5,000 to $12,000 range depending on the scope of work. That price includes removing the existing subfloor, inspecting and repairing joists as needed, and installing new plywood or OSB sheathing to create a solid foundation for your finished flooring.

The biggest cost variable is whether the joists underneath are in good condition or need repair. If the subfloor plywood is damaged from moisture or age but the joists are sound, you are looking at the lower end of that range — roughly $4 to $6 per square foot installed. However, if joists need sistering (adding a new joist alongside a damaged one for structural reinforcement) or full replacement, costs can climb to $8 to $12 per square foot or more. Joist repair alone runs $100 to $300 per joist depending on accessibility. In older Calgary neighbourhoods like Ramsay, Inglewood, Killarney, and Bowness, subfloor replacement is more common because many of these homes were built in the 1940s through 1960s with thinner plywood or even plank-style subfloors that have deteriorated over decades of Calgary's extreme temperature swings.

Material costs for the subfloor sheathing itself are relatively modest — 3/4-inch tongue-and-groove plywood runs about $1.50 to $2.50 per square foot at Calgary building supply stores, while 3/4-inch OSB is slightly cheaper at $1.00 to $1.80 per square foot. The labour to tear out old subfloor, clean up, inspect framing, and install new sheathing is where most of the cost lies. Expect $2.50 to $5.00 per square foot for labour alone, with the higher end reflecting difficult access (tight basements, multi-storey homes) or extensive joist work.

Additional costs to budget for include disposal of the old subfloor material ($300 to $800 for a bin rental in Calgary), any necessary structural engineering assessment if significant joist damage is found ($500 to $1,500), and the building permit fee if structural modifications are involved (typically $150 to $400 through the City of Calgary). If the old subfloor was concealing moisture issues — common in Calgary basements where slab moisture migrates upward — you may also need mould remediation before the new subfloor goes down.

Subfloor replacement is not a DIY project for most homeowners. It involves structural framing knowledge, proper fastening patterns, and ensuring the finished surface is flat to within 3mm over 1.8 metres for the new flooring to perform correctly. A professional installer will also check that the subfloor is properly secured to prevent squeaking down the road. If you are planning a flooring renovation and suspect your subfloor needs attention, getting a professional assessment before choosing your finished flooring is the smartest first step. Browse flooring contractors in the Calgary Construction Network directory at calgaryconstructionnetwork.com/directory?trade=flooring to get matched with installers who can assess your subfloor and provide an accurate quote.