Egress cover comparison · Window Well Covers

Atrium vs. Sloped Egress Window Well Covers: Which Is Right for Your Basement?

By G Harris · November 7, 2026 · Toronto & GTA

Quick answer: Choose an Atrium (Dome) cover if an outward-opening casement or egress window needs extra room to swing open. Choose a sloped cover when a lower profile can protect the well and still leave enough clearance for the window and the cover to open. Both must be assessed for safe access from inside.

A basement window well cover should protect the opening without blocking its purpose. At Toronto homes, the choice often comes down to how the window moves, the available height above the well, and how someone would manually open the cover from inside if the window serves as an emergency exit. Window Well Covers offers custom clear polycarbonate Atrium and sloped egress cover styles for different configurations.

What is an Atrium (Dome) egress window well cover?

An Atrium cover has a raised, dome-like profile. The extra height helps accommodate an outward-swinging casement window that might collide with a flat or low-profile cover. The hinged cover is not automatic: the homeowner opens the basement window first and then manually pushes the cover upward from inside. The design must allow the complete sequence to work without an obstruction.

Because the shape rises above the well, an Atrium design is particularly useful where the window sash extends outward when open. The final height and projection depend on measurements of the actual open window, not just the well opening.

What is a sloped egress window well cover?

A sloped cover follows a lower, angled profile, helping direct some rain, snow and leaves away from the well while keeping natural light coming through its clear polycarbonate. It can be a good option when the window does not require the larger dome clearance. The sloped style offered by Window Well Covers uses a clean, clear design without visually heavy metal framing around the sloped sides.

A lower profile does not automatically mean an easier escape. The window, well and cover must still be checked together to confirm that the window and the cover can both open as intended from inside.

Atrium versus sloped covers: how do they compare?

Which style is right for an outward-opening casement window?

Start with the window in its fully open position. If it swings toward the well and needs substantial vertical space, an Atrium is often the stronger fit. A sloped cover is worth considering when the sash has sufficient clearance and the installed cover still allows manual access. Do not choose solely from a picture: measure the window swing, well projection and available height.

How does the cover open in an emergency?

For the Atrium design shown on the Window Well Covers egress page, the person inside opens the basement window and then manually pushes the hinged cover upward. There is no powered lift or automatically opening hatch. Test the complete movement on the finished installation. For other styles, the opening mechanism and available hand clearance must be verified for the particular window and well.

What does Ontario’s building code say about window well covers?

Ontario’s building code includes requirements for required bedroom egress openings, clearance at window wells and protective enclosures over those wells. A protective enclosure over a required egress window well must be openable from inside without keys, tools or special knowledge. The complete window, well, cover and installation must meet applicable rules; a cover name or style alone does not establish compliance. Check the current Ontario Building Code, Part 9 and seek qualified local advice for the property.

What measurements and photos should you send?

For a useful starting point, supply A (width) across the well at the wall, B (projection) from the wall to the outer edge, and C (height) from the top of the well up to the top of the window. Include a clear front view, a side view and, for an outward-opening window, a photo showing the sash in the open position.

Tell the team whether the window is a casement, slider or another design. Also show nearby steps, pipes, grade changes, sills and other obstructions. Use the A/B/C measurement guide and review measuring and installation.

Can both styles reduce rain, snow and debris?

Yes. Both clear polycarbonate designs can help keep debris and direct precipitation out of the well. A sloped profile encourages runoff, while an Atrium provides raised clearance for a window that needs it. Neither is a watertight basement system, and neither replaces proper drainage or grading.

Do Atrium and sloped covers allow natural light?

Both use clear polycarbonate to let daylight pass through to basement windows. The right choice is still determined first by window operation and egress access, not appearance alone. Homeowners who want a bright basement can also read our natural-light guide.

Which cover should I request for a Toronto home?

If your casement window swings outward into the well, request an assessment for an Atrium-style cover. If a low-profile solution appears suitable, ask about a sloped cover. Provide photos and measurements so the recommendation considers the opening, access and intended use. You can compare product options, see installed examples in the gallery, or request an estimate.

Common questions

Does an Atrium egress cover open automatically?

No. The cover must be manually pushed upward from inside after the basement window is open.

Is a sloped cover suitable for every egress window?

No. It depends on window swing, clearance, access and the installation. The window and cover must be assessed together.

Can I walk on an Atrium or sloped window well cover?

Do not use a cover as a walking surface unless the manufacturer explicitly rates that exact product for foot traffic.

Does a clear cover replace basement waterproofing?

No. The cover can help reduce direct rain and debris entering the well, but the drainage and foundation must still work properly.