Building in Alberta's Climate: Frost, Snow and Freeze-Thaw

Why Alberta is different

Alberta building is shaped by long, cold winters, big temperature swings and deep seasonal frost. Materials and layouts that work fine in a mild climate can heave, crack or fail here, so it pays to choose for the conditions your project will actually face.

Frost and footings

Frost can reach 1.2 m (4 ft) or deeper in many parts of Alberta. When the ground freezes and thaws, it moves, and anything sitting in it, such as deck footings, fence posts and slabs, can be lifted or twisted. That is why footings and posts are normally set below the frost line or designed to handle frost.

Required depths depend on your location and soil. Confirm them with your municipality or a qualified professional before you build.

Snow loads

Roofs, carports and covered decks have to carry the snow load set for your location. Use the sheathing thickness, span rating and rafter or truss spacing your plans call for, and don't downgrade panels to save money. If you are not sure which panel suits your spacing, bring your plans and we will match the span rating.

Freeze-thaw and moisture

Repeated freezing and thawing pushes moisture into wood and then expands it, which speeds up cracking and rot where wood stays wet. Use pressure-treated lumber for anything at or near the ground, and keep untreated lumber off the ground and covered with a breathable tarp on site.

Dry air and chinooks

Alberta's dry air and sudden chinook warm-ups can dry wood quickly, leading to checking (surface cracks), cupping and shrinkage in decks and fences. Let treated lumber acclimatize, seal or stain it once it has dried, and consider composite decking if you want a low-maintenance surface.

Working and storing materials in winter

• Store lumber and panels flat, off the ground and covered so snow and meltwater can't soak them.
• Leave the recommended expansion gap between panel edges, typically 3 mm (1/8 in), because panels swell and shrink with temperature and moisture.
• Don't pour concrete on frozen ground, and follow cold-weather concreting guidance.
• Use fasteners and connectors rated for treated lumber and for outdoor exposure.

Permits, codes and utilities

• Check with your municipality about permits. Many require them for raised decks, garages, larger sheds and structural work.
• The Alberta Building Code sets the minimum requirements. Ask your municipality which edition and local rules apply to your project.
• Contact Alberta One-Call before you dig so buried utilities are located first.
• Use your Real Property Report (RPR) to confirm property lines before placing a fence, deck or shed.