DIY exterior storm windows

Q: I would prefer do-it-yourself exterior storm windows to expensive replacement windows. Is there a good, effective and inexpensive design for do-it-yourselfers?

A: Low-cost, home-made exterior storm windows can improve efficiency of any existing window, assuming the existing windows are in reasonably good condition. If your windows are extremely leaky, and perhaps have rotting wood frames, your best long-term choice is replacement windows. Carefully inspect the weatherstripping, caulking and frames on your windows before making any decisions.

Installing exterior storm windows can be a wise choice for some homes, but they are not an alternative to replacing old, leaky defective primary windows. You must make sure your existing primary windows are reasonably airtight and in good condition before considering installing storm windows. Check condition of their caulking and weatherstripping.

Exterior storm windows, because they create a dead space over your primary windows, increase the insulation value of the entire window opening, not just the glass pane area. Also, storm windows protect your primary window from the ravages of bad weather or ill-directed baseballs. Security of your window can be substantially improved if you select the proper type of plastic glazing.

There are many designs for making exterior storm windows yourself. The one you select depends upon your woodworking skills and the final appearance you desire. The simplest designs can be as energy efficient as more complex designs, but they just will not look as finished or professional and may not last as long.

The first step is determining the type of clear plastic glazing to use. Glass is heavy and dangerous to work with, so clear acrylic (Plexiglas) is commonly used instead. Acrylic holds up well in the sun and is easy to cut and shape. Although it is tougher than glass, it will crack from a hard impact.

A stronger option is using polycarbonate glazing. This is what is used for bulletproof glass. A baseball should bounce off of polycarbonate glazing. It is more expensive than acrylic and it may yellow slightly over time in the bright sun.

Another extremely tough material is double-walled, ribbed polycarbonate. You can find it at most home centers. It also provides the highest insulation value from all the dead air spaces between the ribs. Its drawback is its higher cost and the ribs distort the view from indoors. Natural lighting will still come through.

Measure the exterior window opening about one-half inch out from the existing window. A smaller air gap between the storm window and primary window is more efficient than a wide gap. Window openings are seldom square, so measure the width at top and bottom and the height at each side. Size the storm window frame three-quarter inch smaller than the window opening to leave room for foam weatherstripping to hold it in the opening.

For the simplest construction, use 1-by-2-inch lumber. It is probably larger than is required for strength, but the larger wood makes it easier to create strong corner joints. If you are an experienced woodworker, use smaller lumber for a nicer appearance. Cedar or redwood will hold up the best and looks nice.

Use a simple lap joint, not a weak butt joint, at the frame corners and screw the clear plastic glazing to it. If you have a router, cut a slot for the glazing. This looks better and makes an overall stronger window. If you notice condensation problems, drill several small weep holes through the bottom frame member.

Q: I use a fireplace to help heat my two-story house. I am concerned about safety when I go to bed at night with it still burning. What is a good safety plan to have in case a house fire does start at night?

A: First of all, never go to bed or leave the house when a fire is burning or even just smoldering. A good fire safety plan always includes smoke detectors and several routes to exit your house in case of a house fire. Keep a bright emergency flashlight near your bed.

For your second floor bedrooms, install a fire escape ladder. Werner ( offers a complete two-story kit. It mounts securely inside the wall under a window so it is out of the way when not needed.

• Send questions to James Dulley, Daily Herald, 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit

© 2024 James Dulley

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