Broken storm window

Q: When I was replacing the summer screens with winter storm windows last week, I found that a shovel handle had fallen against the stacked windows, cracking the top one. These are metal frame storm windows, and I’m not sure that a replacement is available. Is it possible to replace the glass myself? — John H., Concord, N.H.

A: It is possible to do the replacement yourself, but be sure to wear heavy work gloves for safety when removing or installing the glass. If the cracked glass is still in one piece, cut two pieces of cardboard to the same size and tape securely against both sides of the glass and around the window frame. Take the entire storm window to the home-improvement store (or, to the window’s manufacturer, if possible).

Employees can help you find either a replacement storm window, or glass of the same dimensions as the original.

(Readers who have storm windows with shattered glass need to remove all broken glass and measure the dimensions of the frame to find the right size replacement glass.)

If you need to replace the glass, you’ll need to purchase rubber gasket material and any replacement hardware so that the glass seats correctly in the frame. Working in a safe area, remove the damaged glass by unscrewing the retaining screws from the top rail and carefully sliding the rail from the glass. Pull downward gently, and be careful not to damage the L-shaped corner keys of the frame.

Fitting the new rubber gasket to the new glass can be a challenge for a first-timer. The gasket should be twice the thickness of the inside edges of the frame opening, and must be placed around the glass pane before installation. Wear gloves and carefully fit the gasket to the glass. At the corners, you’ll need to make a little cut in the gasket to make it fit comfortably. Cover all four sides and trim away the excess.

Slide the glass into the channels on the sides and push down into the bottom of the frame. (This may be a two-person job.) Once seated, replace the corner keys in the top sides of the frame and the ends of the top rail. Gently push the top rail into place until the top and side corners are flush. Replace the retaining screws.