Can I start my addition in October and finish before winter in Ottawa?

Starting an addition in October is risky but not impossible. It depends on the scope and on how much of the weather-sensitive work can be finished before sustained cold arrives. Ottawa usually sees frost and freezing nights through the fall, and the key milestone is getting the addition closed in, with the foundation done, framing up, roof sheathed and covered, and windows in, before the weather turns for good.

The foundation is the biggest challenge for a fall start. Concrete can be poured in cold weather, but it needs protection such as insulated forms, blankets or heated enclosures and adjusted mixes, all of which add cost. The later the pour, the more of these measures you'll need. Footings in clay or soils that aren't clearly defined must be at least 1.2 m deep and not less than the depth of frost penetration, and the ground under them must not be frozen when concrete goes in. For some smaller additions, helical piles are an alternative your engineer may consider; ask whether they suit your soil and design.

If the structure is closed in before winter, interior work such as electrical, plumbing, HVAC, insulation, drywall and finishing can continue through the cold months with temporary heat. Ask who supplies and pays for temporary heat, and whether your existing system can be connected early.

Late-season building usually costs more than summer building because of cold-weather measures, temporary heat and weather delays. On the other hand, some contractors have more availability in the fall. Ask each contractor to price the cold-weather items separately so you can weigh them against waiting until spring.

A practical alternative is to use the fall and winter for design, engineering, permits and contractor selection, then break ground in spring when conditions are easier. This can get you into the finished addition just as soon, because you avoid weather delays and cold-weather surcharges. An addition over 10 square metres needs a building permit; ask the City for current timelines so you can plan when to apply.

Whichever way you go, get a written schedule with milestones and a plan for what happens if the weather turns early. You can browse addition contractors in the Ottawa Construction Network directory at justynrookcontracting.com, ask about their availability, and compare quotes.

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Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:

• Homeupgraders
• RenoMotion Inc.
• L.L. Renovation
• Nic’s D.U.C.T Works Inc
• Capital City Drywall