Can I add windows to my garage and what should I know about doing this in Ottawa?

Adding windows to a garage is absolutely doable and makes a dramatic difference in the usability of the space, especially if you are converting it to a workshop or living area. In Ottawa, expect to pay $800 to $2,500 per window opening including the window unit, framing, and exterior finishing.

The process involves cutting an opening in the garage wall, framing it with a proper header to carry the load above, installing the window, and finishing both the interior and exterior. The header size depends on the opening width and the load above. For a standard 36-inch window in a single-storey garage wall, a doubled 2x8 or 2x10 header is typical. If the garage has a room above it or carries roof trusses, the structural requirements increase and you should have the header size confirmed by someone familiar with the Ontario Building Code span tables.

For living space conversions, the OBC requires natural light equal to at least 5 percent of the floor area. A two-car garage with roughly 400 square feet of floor space needs at least 20 square feet of window area, which translates to roughly three or four standard windows. You also need at least one egress window that meets minimum size requirements for emergency escape if the space will be a bedroom.

Window selection matters in Ottawa's climate. Triple-pane windows with low-E coatings and argon gas fill are standard for new construction here, and you should not go with anything less for a garage conversion meant for year-round use. A quality triple-pane casement or awning window costs $400 to $900 per unit before installation. Double-pane is cheaper but will create a cold spot in the wall during deep winter cold snaps and may develop condensation issues.

Placement is worth thinking through carefully. South and west-facing windows provide passive solar heat gain in winter, which is genuinely helpful in Ottawa. North-facing windows provide consistent diffused light without glare, which is ideal for a workshop. East-facing windows give you morning light. Avoid placing windows where they will be blocked by shelving or workbenches on the interior or where water runoff from the roof hits them directly on the exterior.

If you are adding windows to an attached garage, be aware that the fire separation requirements in the OBC restrict window placement on walls that are close to the property line. Generally, walls within 1.2 metres of the property line cannot have unprotected openings. This is rarely an issue for detached garages set back from the lot line, but it can limit your options on side walls of attached garages on narrow Ottawa lots.

You will need a building permit from the City of Ottawa for cutting new openings in exterior walls. The permit process is straightforward and typically takes two to three weeks for approval. Your contractor should handle the application, but verify that they pull the permit before work begins.

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

• Justyn Rook Contracting
• JC Carpentry
• Steven Labelle - Your Complete Home Renovator
• ALTIOR CONSTRUCTION
• Geerts Roofing Inc