Window Well Cover Materials Compared

Window well covers are sold in a handful of common materials, and the differences between them matter more than they look like they would at first glance — especially once you factor in a Wisconsin winter and, for any well over an egress window, the requirement that the cover stay easy to open from inside.

Polycarbonate (clear or tinted dome/bubble covers)

Polycarbonate covers are the most common style for residential wells. They're molded into a raised dome or bubble shape that sheds water and lets daylight reach the window below.

• Light transmission is the main advantage — a clear or lightly tinted polycarbonate cover keeps the basement room behind the window from going dark, which matters most for a finished bedroom or living space.
• Weight is relatively low, which generally makes them easier to lift or swing open by hand than a heavier metal cover.
• UV exposure over time can cause clear polycarbonate to yellow or become brittle after years in direct sun, depending on the specific product's UV-resistant coating. That's a maintenance consideration more than a safety one, but a cover that's gone brittle is more likely to crack under snow load or an accidental step.
• Attachment style varies — some are simply set into a bracket around the well's rim, others are hinged. For a well over an egress window, the attachment has to allow the cover to be pushed open or lifted off from inside without needing a key, latch release tool, or any hardware beyond hand pressure.

Metal grate covers

Grate-style covers — typically galvanized steel or expanded metal mesh — are common on older wells and on wells that see heavier foot traffic or debris.

• Durability under load is generally the strongest argument for a metal grate: they tend to hold up well to snow accumulation and incidental foot traffic compared to a lighter dome.
• Corrosion is the trade-off. Galvanized coatings resist rust for a long time but not indefinitely, especially where road salt, gutter runoff, or standing moisture reaches the metal. A rusted-through grate can weaken unevenly, which is worth checking periodically rather than assuming the cover is still sound because it looks intact from above.
• Light transmission is much lower than polycarbonate — a solid or tightly meshed grate can noticeably dim a basement window.
• Weight is higher, which is part of why they hold up to load well, but also means the cover has to be genuinely easy to lift from inside, not just liftable in theory. A heavy grate that's difficult for a child or an older adult to move is a real problem if that window is a bedroom's only second exit.

Aluminum-framed covers with a polycarbonate or mesh insert

These pair a lightweight aluminum frame with either a polycarbonate panel or a mesh insert set into it, aiming to combine a lighter overall cover with more structure at the edges than a bare dome.

• Balance of weight and rigidity is the appeal — the frame adds strength at the perimeter where a cover is most likely to flex or slip out of place, without the full weight of a solid metal grate.
• Corrosion resistance is generally better than steel, since aluminum doesn't rust the way steel does, though the fasteners holding frame to insert are still worth checking over time.
• Cost and availability vary more by manufacturer than the other two categories, since these are less standardized.

Wood and improvised covers

Plywood or scrap-lumber covers show up occasionally as a homeowner-built solution. They're worth calling out mainly to flag the downsides: wood absorbs moisture and rots from repeated exposure to rain and snowmelt sitting on top of it, it doesn't transmit light, and a homemade cover is far more likely to end up fastened down in a way — screws, a padlocked hasp, a strapped-down tarp — that a person inside the room can't undo quickly or at all. Over a window that's a bedroom's required exit, that's the exact failure this site's safety guidance is warning against; see do window well covers interfere with emergency egress?.

What to weigh beyond the material itself

Whatever material you choose, three questions matter more than which one you pick:

1. Does it fit this specific well's dimensions, including the areaway width and projection the well was built to under Wisconsin's Uniform Dwelling Code? A cover cut for the wrong footprint leaves gaps or doesn't seat securely.
2. Can a person inside the room open or remove it without tools, every time, including after snow or ice has settled on it? This applies to every material equally — a lightweight polycarbonate cover latched down with a padlock is just as much a problem as a heavy metal grate bolted shut.
3. What load is it actually rated for — snow only, or snow plus occasional foot traffic — and does that match how the area around the well gets used? Snow load and foot-traffic load on window well covers covers that question separately.

For how a cover fits into the rest of a window well setup — sizing, drainage, and when a cover is the right call versus a well repair — see window well covers and do you need a window well cover?.