A window to your world

New windows can breathe fresh life into an older home, and they are one of the deciding factors in the longevity of any new structure.

Successful window installation is possible even for beginner DIYers, but the approach you take depends on whether you are replacing old windows in an existing structure or installing windows in a new building.

The time it takes to install a window depends on its size. Start with smaller windows; they are easier to install. Excluding the time taken to remove an old window, which can vary widely, installation takes two to four hours for someone with no previous experience.

Out with the old

Replacement windows are designed to slip within existing window jambs (the framed opening of a window) after the old sashes (the frame that holds the glass pane or panes of a window) have been removed. This is the simplest way to upgrade your windows, and you won’t have to add new trim or flashing because they were installed with the old window.

Start by measuring the width and height of your window opening, and then subtract an allowance for the gap required to let the new window fit easily and receive caulking. How much gap is enough? That depends; use a level to determine if the top and bottom of your existing window opening are plumb and level.

If the opening is square and true, then a centimetre or so gap on all four sides will do nicely. But if your window opening has a bowed side or an area that’s not level or plumb, then give the gaps a larger width. Few things are more discouraging than suddenly discovering that your brand-new windows are too big to fit into the openings. If you think you’ll have trouble like this, order replacement windows that are slightly shorter and narrower than the opening.