Keeping a home's window and door screens in good condition can help ensure effective insect control and ventilation in warm weather.
Modern screening is generally flexible fiberglass or aluminum that is easily punctured or cut, and even small openings cause a screen to lose much of its effectiveness for insect control. Fortunately, most screens are fairly simple to repair or replace.
Homeowners who replace a screen can use special screening to help control heat gain and sun glare through windows.
Small punctures in fiberglass or aluminum screens often can be repaired almost invisibly by spanning the puncture with a transparent caulk, adhesive sealant or even a clear household cement. A waterproof adhesive sealant or caulk is best. Apply a little sealant to the punctured area and spread it with a small stick or piece of cardboard. Check the sealant when it cures to make sure it covers the entire puncture; if not, apply a second coat to fill the gap.
Small tears can be mended by aligning the edges and holding them in place with tape on one side of the screen. Apply sealant to the edges on the other side. Let it cure for a few minutes, and remove the tape.
Larger holes can be patched with screening of the same type and color. Patches can be held in place with clear adhesive-sealant, or can be sewn in place.
Here is an old but effective way to hold a metal-screen patch in place:
Cut a square or rectangular patch and pull a few strands of woven wire from each side to form edges of protruding wires. Bend the protruding wires at a right angle to the patch and push the wires through the screen around the torn area. Fold down the protruding wires to hold the patch in place.
Aluminum and fiberglass screens in metal frames also are fairly easy to replace. Screens are usually held in place in these frames with spline, a slender, rubber-like rope that locks into a groove.
A special tool called a spline roller, which has a concave-edged wheel at one end and a convex-edged wheel at the other, is needed to replace the screen. The tool sells for a few dollars at home centers and hardware stores, where spline and replacement screening also can be bought.
Here is the procedure for replacing fiberglass screen in a splined frame:
* Place the screen on a flat surface, spline side up. Pry out the end of the old spline with a knife or small screwdriver, and pull it out. The screen can then be removed from the frame.
* Cut a new piece of screen, slightly oversized. Place it on the frame so it overlaps one spline groove -- the starting side -- by about 1/8 inch. Cut a small piece of screen off the starting corner at a 45-degree angle to avoid wrinkling. Place spline over the screen and groove at the starting corner.
* Using the concave wheel of the roller, press screen and spline into the groove at the same time. The screen must be kept straight with the edge of the frame while rolling. Roll in all four sides, stretching and adjusting the screen and cutting off corners as the installation progresses.
* Trim excess screen with a sharp utility knife.
Aluminum screen is installed in much the same way, except the screen is first rolled into the groove on one side without the spline, using the rounded-edge roller wheel of the spline tool.
When the aluminum screen is in position on the first side, roll the spline into the groove over it, using the concave wheel of the tool. Cut the screen at a 45-degree angle at the second corner and work around the frame, using the same procedure on each side (rolling in the screen first, then the spline). Trim the screen with scissors or a knife.
Readers' questions and comments should be sent to Gene Austin, c/o The Baltimore Sun, Box 8263, Philadelphia, Pa. 19101.