We make covers for a living, so treat what follows accordingly — but a homemade cover is a perfectly reasonable thing to build, and for some wells it is the sensible answer. Here is how to do it properly, and where it tends to go wrong.
What the cover actually has to do
Four jobs. A design that misses any of them will annoy you within a year.
- Shed water — which means it has to slope away from the house, not sit flat.
- Carry snow — a wet spring snowfall is heavier than people expect, and it lands all at once.
- Come off easily — you will need to clear the well, and if the window is a bedroom exit somebody must be able to push it up from below.
- Not trap moisture — a sealed lid over a damp well turns into a condensation box.
The usual build: wood frame and a clear sheet
The common design, and the one that works best, is a rectangular frame with a clear panel in it.
- Measure the well across the top — width along the wall, and how far it stands out. Add an inch each way so the frame sits on the lip rather than dropping inside it. Measure the widest point if the well is out of square.
- Build the frame from pressure-treated 2x3 or 2x4, halved or screwed at the corners, square it before the fixings go in.
- Add a centre rail across anything wider than about four feet. This is the part people skip and it is the part that stops the panel bowing under snow.
- Fix the panel. Twin-wall polycarbonate is the right material — it carries load, it does not shatter in cold, and it passes light. Acrylic and thin PVC both go brittle in a prairie winter. Screw through oversized holes with washers so the sheet can move with temperature; screwed down tight, it cracks.
- Give it a fall. Pack the back edge up so water runs off the front. Level is the most common mistake in a homemade cover.
- Hold it down, not shut. A hinge along the back and two turn buttons at the front. Wind will take an unsecured cover; screws all round will trap somebody.
What it costs
Timber, a sheet of twin-wall polycarbonate, fixings and a hinge comes to somewhere in the region of a hundred dollars for a typical well, plus an afternoon. That is real money saved against a bought cover, and if you already have the tools and the offcuts it is more.
Where homemade covers fail
Snow load. No centre rail, or too thin a panel, and the first heavy fall bows it into the well. If you build nothing else into the design, build in the rail.
The wrong plastic. Cheap clear sheet yellows within a couple of seasons and goes brittle enough to crack when you lift it. Twin-wall polycarbonate costs more and is the difference between a five-year cover and a one-year one.
Rot at the back edge. The frame member against the house stays wet longest. Treated timber, and a gap rather than tight contact with the wall, both help.
Egress. The serious one. If the window is the way out of a bedroom, a homemade cover screwed down at four corners is a hazard, not a feature. Hinge it, and test that it opens from inside the well.
When buying is the better call
Three cases, honestly.
If the well is an odd size, a bought cover made to your measurements is no harder to get than a stock one, because they are cut to order either way. If you get heavy snow, a welded metal frame carries what a timber one will not. And if the well is visible from the street, a wooden box tends to look like a wooden box.
If none of those apply, build it. It is a good weekend job.
If you would rather not
Ours are made in Canada in 42 sizes, steel or aluminum, with a clear panel available on any of them — see the range, or read how the materials compare first. If you are still deciding whether you need one, start here.