How to Install a Replacement Window Into a Brick Facade

Extend the measuring tape from one side of the window to the other to determine its width. Do this across the bottom, center and top, recording the smallest measurement.

Extend the measuring tape from the lower edge of the upper frame to the top of the sill to determine the window’s height. Again, calculate this measurement in three places -- toward the right, the center and the left, and record the smallest measurement. Subtract 1/2 inch from each recorded measurement when ordering the new window. This ensures the window fits the trim.

Pry loose the wooden stops along the lower sash to loosen and free it. Press the trim inward to pull the upper sash forward and away from the window. Also pry loose aluminum or vinyl trim or liners from the window using a flat pry bar. Work carefully to avoid damaging the trim.

Prepare the opening in the wall before installing the replacement window. Carefully scrape off peeling paint from the edges using a paint scraper. Insert tinted wood putty into any cracks or holes using a putty knife. Sand the patched section of the opening when cured, and touch up with paint to blend with the surrounding frame. Alternatively, apply a fresh coat of paint over the entire frame, and allow it to dry.

Insert the bottom of the replacement window inside the opening, above the sill. Tilt the window's top up to fit it into the upper section of the opening. Push this window tight into the opening, until it rests on the exterior casings.

Place a level on a side of the window to ensure it is square and level. If needed, insert wood shims into the sides and base of the window until it is square.

Drive 2-inch screws through the predrilled holes in the window and into the wood frame.

Fill the gaps between the frame and window from inside with expanding foam. Step outside and put the trim you removed back in place around the window using a nail gun and nails. Fill any gaps between the window and trim using a caulking gun and elastomeric caulk.