Why Your Windows Are Sticking: The Truth About Improper Installation

1. Level (The horizontal plane)

Level refers to the horizontal axis. We ensure the head (top) and the sill (bottom) are perfectly flat. If a window sill isn't level, water can pool in the tracks instead of draining out through the weep holes, a recipe for rot in a climate as wet as ours. If that header isn’t level, you aren't just dealing with a crooked look, you’re are potentially dealing with a structural "squeeze" which can lead to jammed locks, foggy glass, and expensive energy leaks."

2. Plumb (The vertical plane)

Plumb is the vertical equivalent of level. While "level" deals with the horizontal, "plumb" ensures the unit is perfectly upright. To get this right, an installer has to check the vertical line from two different perspectives:

• Face View (Side-to-Side) This is what you see when standing directly in front of the window. If the side jambs lean to the left or right, the window sash will drag or stick because it’s fighting gravity.
• Depth View (Front-to-Back) This is how the window sits within the thickness of your wall. If the window leans toward the backyard or toward your living room, you’ll experience the "ghost door" effect, where a door or window slowly swings open or shut on its own.

A: Straight from the front (Face Plumb).
C: Perfectly upright within the wall (Depth Plumb).
B & D: Leaning too far in or out. This causes windows to stick, locks to jam, and, most dangerously, forces water into your home’s frame instead of draining outside, leading to hidden rot and mould.

Why it matters in Ottawa If the Depth View isn't plumb, your window's drainage system can fail. Rain and melting snow need to flow out toward the exterior; if the window leans inward, that moisture can be pulled toward your home's wooden frame instead.

3. True (the square & straight)

A unit is "True" when it is perfectly square (all corners at 90 degrees) and not twisted. If a frame is "cross-cambered" (twisted), the sash won't sit flush against the weatherstripping, leaving a gap for Ottawa’s winter winds to whistle through.

Operation frustration

As the house settles and the seasons change, a window that wasn't installed "True" will start to stick. You shouldn't have to be a weightlifter to open your kitchen window for some fresh air.

Failed Seals & Foggy Glass

Ottawa’s extreme temperature swings cause materials to expand and contract. If a window is forced into a frame that isn't square, that stress eventually snaps the insulated glass seal, leading to that unsightly permanent fog between the panes.

The "micro-draft"

You might have the best R-value glass on the market, but if the frame is twisted, your expensive heated air is leaking right out of the gaps.

Structural rot

This is the most dangerous consequence. When units aren't level and true, water can bypass the flashing and seep into your wall cavity. By the time you see the mould or bubbling drywall, the damage to your home’s "bones" is already done.

Load-bearing support

We place shims at every critical fastener point and directly behind the hinges of every door. This provides a solid, stable backing that prevents the frame from "bowing" or "twisting" when the house naturally settles.

Balanced spacing for a weather-tight seal

By using shims to create a perfectly uniform "reveal" (the space between the window sash and the frame), we ensure that the weatherstripping compresses evenly. This is what keeps those biting Ottawa winds outside where they belong.

Stability for the long haul

Proper shimming ensures that the weight of the window is distributed evenly across the structural header. This prevents stress on the glass units and protects the integrity of the seals, even during our intense freeze-thaw cycles.