What type of siding is best for a home addition in Ottawa's climate?

Choosing siding for an addition affects how the house looks, how much maintenance it needs and how well the wall handles moisture for decades. Ottawa's climate is hard on exteriors, with deep winter cold, hot summers, frequent freeze-thaw cycles, ice storms, driving rain and strong summer sun. Not every material handles all of that equally well.

Fibre cement siding is a strong performer in a cold climate. It resists moisture, moves less with temperature changes than vinyl, isn't attractive to insects or woodpeckers, and won't burn the way vinyl and wood can. It comes primed or pre-finished and can be painted to match your house. It is heavier and harder to cut than vinyl, so installation takes more labour.

Engineered wood siding gives the look of wood at a lower cost than fibre cement in many cases. It performs reasonably well when properly painted and maintained, but it needs repainting over time and is more vulnerable to moisture at cut edges and joints. If your house has wood siding and you want a close match, engineered wood can often be milled to similar profiles.

Vinyl siding is usually the most affordable option, and insulated vinyl products have improved in appearance. It does have limits: it becomes more brittle in deep cold and can crack from impacts, and it expands and contracts a lot, so it has to be fastened loosely enough to move. Lower-quality vinyl can warp or fade. If you choose vinyl, ask about thickness, the warranty terms in writing, and how the installer handles expansion.

Brick veneer is the most durable choice and is common on many Ottawa homes. It needs little maintenance but usually costs the most, and matching the colour and texture of existing brick can take extra sourcing. The foundation must also be designed to carry the veneer, so brick has to be decided before the foundation is designed.

Whatever you choose, what goes behind the siding matters as much as the siding. A sheathing membrane or housewrap and a drainage plane, often with a small air gap created by furring strips or a drainage mat, let water that gets behind the cladding drain away and the wall dry out. Ask your designer what the drawings require, and ask each contractor whether their price includes the drainage gap and proper flashing at windows, doors and the base of the wall. Poor flashing and drainage details are a common cause of rot behind siding.

For an addition, also think about how the new siding will meet the old wall and whether you want to match the house exactly or contrast it on purpose. Compare itemized quotes from cladding contractors that state the material, the profile, the membrane and the trim.

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

• Justyn Rook Contracting
• JC Carpentry
• The Granite shop
• L.L. Renovation
• Denys Builds Designs Renovations