Fitting a cover is a twenty-minute job once you have the right size. Getting the right size is where it goes wrong, because a cover is sized to the well, not to the window.
This covers framed steel and aluminum covers, the moulded plastic dome type, and the two situations that change the job — a bedroom window, and a well that sits under a deck.
Measure the well first
Two numbers, both taken across the top of the well where the cover will actually sit:
- Width — along the house wall, outside edge to outside edge.
- How far it stands out — from the wall to the outer lip.
Measure at the top, not at the base. A well that has been in the ground a while is usually wider at the top than at the bottom, and the top is what the cover has to clear.
If the well is out of square — one side pushed in, the lip bowed — measure the widest point in each direction and order to that. A cover slightly too big rests fine. A cover slightly too small does not rest at all. There is more on taking measurements in our guide to measuring a window well.
How to cover a basement window well
A framed cover sits on the lip of the well and against the house wall. Nothing needs cutting and nothing needs to go into the well itself.
- Clear the lip. Sweep off the soil and gravel that has built up on the rim, so the frame sits flat instead of rocking on a stone.
- Set it in place dry. Put the cover on with no fasteners and look at it from the side. The back edge should sit tight to the wall and the front should sit on the lip with no daylight under it.
- Slope it away from the house. If the cover sits dead level, water sits on it. A small fall toward the outer edge is what sheds rain and melting snow. On a flat lip, a strip of treated wood or a couple of packers under the back edge gives you that fall.
- Fasten the back edge. Masonry screws or sleeve anchors through the rear frame into the foundation, two or three across the width.
- Clip the front. Turn buttons, a hasp, or spring clips at the outer corners. Enough to stop wind lifting it, not so much that it takes tools to remove.
How to attach a window well cover without drilling the foundation
Not everyone wants anchors in the wall, and on some older foundations you should not put them there.
The alternatives, in order of how well they hold: brackets that clamp onto the lip of the well itself; turn buttons fixed to the well rather than the house; or, on a well with an outward lip, the weight of the cover plus two corner clips. Weight alone is not enough in a place that gets real wind — a framed cover will move.
Bubble and plastic dome covers
Moulded plastic covers fit differently. Instead of resting on the well, most mount to the house wall along the top edge and curve out over the opening, with the lower edge held down by the soil or a strip of trim.
Two things to get right. Fix the top edge to the wall so water runs over the flange rather than behind it — a bead of sealant along the top makes the difference. And leave the lower edge able to breathe; sealing a dome completely tends to trap condensation against the window.
If you are deciding between a dome and a framed cover, we compare plastic and steel here.
If the room is a bedroom
This is the one rule not to improvise around. If the window is the way out of a bedroom, whatever sits over it has to open from inside the well, by hand, with no tools and no key.
That rules out screwing the cover down all the way round, and it is a good reason to choose a lighter aluminum cover over a steel one on that particular opening — somebody may have to push it up from below. Your building department can tell you what applies; our guide to bedroom window requirements has the background.
Can you cover a window well with a deck?
You can build a deck over a window well, and plenty of people have, but it changes three things and you should decide about all three before the joists go on.
Light and air. A solid deck over a well makes the room below dark. Spacing the boards helps, but you will lose most of the daylight either way.
Water. A deck is not a roof. Rain comes through the gaps and lands in the well, so the well still needs to drain — and now it is harder to reach in order to clear it. Build in a removable hatch panel directly over the well.
Escape. If the window is a bedroom exit, a deck over it is a serious problem: somebody climbing out must be able to get clear. Most inspectors will want a hatch that opens from below, or the deck kept off that window entirely. Ask before you build, not after.
Keeping it working
Lift the cover twice a year and clear what has collected underneath. A cover keeps the well clean, but it does nothing about groundwater coming up through the base — if the well still holds water with a cover on it, the problem is underneath, and this is how to find it.
What we make
Every size we roll a well in, we make a cover for — 42 sizes in steel or aluminum, with a clear panel available on any of them, all made in Canada. See all window well covers.