Aluminum screen know-how

Spring is the best time to rebuild your bulwark against bugs with a window screen repair blitz. Replacing mesh or even rebuilding entire new screen frames is a breeze when you know the basics I'll tell you about here.

Aluminum window screens are typically made of factory-painted extrusions that has several key features. First of all, its hollow shape is made to accept preformed 90-degree aluminum or plastic corner clips that hold the frame sides together. Another feature is the narrow channel found along one of the outside faces. This channel accepts a flexible strip of rubber or foam called a spline. The spline is compressed into the channel over top of the mesh during installation, anchor and tightening it at the same time.

Screen-making supplies are usually found on hardware store shelves. Aluminum extrusion is typically sold in 12-foot lengths, corner clips by the piece and spline by the foot off a roll. Mesh is also sold off rolls of fixed width, typically starting at 24"-wide and working up.

What makes aluminum-framed screens so easy to build on your own is a little-known fact about cutting frame members. Any electric mitre saw with a carbide-tipped saw blade is quite capable of cutting the soft aluminum extrusions used for screen frames. Aluminum downspouts and eavestrough can also be cut in the same way. You could use an ordinary hacksaw to cut frame material as well, though you'd have to be careful to get the corner angles right.

After cutting frame pieces, fit corner clips into the ends of the aluminum frame extrusions. If your frames don't hold together reliably with friction alone, squirt a small blob of silicone caulking into the ends of the frame extrusions before assembly. Once dry, it'll hold things together, yet still allow you to take the frame apart later for repairs.

There are two main kinds of window screen mesh available: aluminum and fiberglass. Fiberglass is the option I prefer because it combines low cost, good looks (it's dark coloured and hard to see) with great flexibility that makes installation easier. Fiberglass mesh is also reasonably tough and lasts a long time. The technique for installing mesh on a new screen frame is the same as that for replacing damaged mesh on an old screen.

Begin by cutting a piece of mesh that's about 1 1/2" longer and wider than the inside dimensions of your frame. Place the frame on a large, flat surface with its spline channel facing up and lay the mesh on top. The object here is to orient the mesh so it's parallel to the sides of the frame and to preserve that orientation as the spline is installed and mesh pulled tight. This is easier than it sounds because the mesh is stretchable and can veer out of alignment as you work along one side. Steering the installation of mesh is all about pulling it one way or the other with your hands in that area that's just in front of the point at which the spline is being pushed home. Take a length of spline material in your off-hand and a wide-bladed stubby slot screwdriver in you dominant hand and begin to push the spline into the extrusions slot with the mesh underneath. You'll immediately see how this action draws the mesh down and acts to tighten it as installation progresses. If you're having trouble getting the screwdriver to do the work, a wheel-tipped tool is available to do the job. Continue to work your way around the frame, always being conscious to keep the squares of the mesh parallel to the sides of the frame. When you've "splined" your way back to the starting point, cut the spline to length so it butts tightly against the end you began with. Use a fresh utility knife blade to trim away the excess mesh that extends beyond the spline. That's it! You're bug-safe now.