What is aluminum capping on Ottawa window trim?

Aluminum capping (also called aluminum cladding or coil cladding) is the process of wrapping existing wood window trim, fascia, and exterior frame components with thin, pre-formed aluminum sheeting. It's a popular finishing technique in Ottawa because it eliminates the need to repaint exterior trim and protects the underlying wood from moisture, rot, and our harsh freeze-thaw cycles.

How It Works

A sheet metal worker or experienced window installer bends aluminum coil stock — typically 0.019" to 0.024" thick — to match the exact profile of your existing trim boards. The formed aluminum is then fastened and sealed over the wood, creating a weather-tight shell. The result looks clean and finished, and the aluminum is available in dozens of colours to match or complement your window frames and siding.

Why Ottawa Homeowners Choose It

Ottawa's climate is particularly hard on painted wood trim. We get significant temperature swings, ice damming conditions, and prolonged moisture exposure through spring thaw — all of which cause paint to peel and wood to absorb water and eventually rot. Aluminum capping essentially eliminates that maintenance cycle. Once it's on, you won't be scraping and repainting that trim every few years.

It's extremely common to have aluminum capping done at the same time as a window replacement. The contractors we match you with will often include capping of the surrounding trim as part of a complete window installation, ensuring a tight, weatherproof seal between the new window frame and the house exterior.

What to Ask a Contractor

When getting quotes, ask whether capping is included or priced separately, what gauge aluminum they use, how they handle the corners and joints (tight mitered corners vs. overlapping), and whether they back-caulk behind the aluminum before fastening. Proper sealing behind the cap is important — poorly installed capping can actually trap moisture against the wood rather than protecting it.

If you're replacing windows and want to know what capping would add to your project cost, feel free to submit your details through Ottawa Window Pros and get matched with local contractors who can give you a complete picture.