When planning an egress window, Wisconsin homeowners often discover that the best basement wall is directly underneath a deck or porch.

That raises an important question:

Can an egress window be installed under a deck?

In many cases, yes.

Wisconsin code allows egress windows beneath decks and porches as long as there is a clear escape path leading to an open yard or exterior space.

The important part is not just the window itself. Homeowners also need to consider the window well, deck structure, drainage, excavation access, and emergency escape route.

Wisconsin Code Allows Egress Windows Under Decks

Wisconsin SPS 321.03 allows an egress window underneath a deck or porch when there is a clear path at least:

• 36 inches high
• 36 inches wide
• No more than 15 feet long before reaching an open exterior area

This is important because an egress window must provide more than a large opening. Someone needs to be able to exit the basement, leave the window well, move beneath the deck, and reach a safe outdoor space.

The Entire Escape Route Matters

A compliant window can still become a problem if the area outside is blocked.

Homeowners should think about the complete route:

Basement Bedroom → Egress Window → Window Well → Under the Deck → Open Yard

Common obstacles can include:

• Deck posts
• Stairs
• HVAC equipment
• Storage
• Landscaping
• Fencing
• Patio furniture

The route should remain clear even after the installation is complete.

Window Well Requirements Still Apply

Installing an egress window beneath a deck does not eliminate normal window well requirements.

If the opening is below grade, a properly sized well is still required. The well generally needs to provide at least 36 inches of clearance from the foundation wall.

Depending on depth, steps or a ladder may also be required.

This is where deck posts and footings can become important. A proposed window location may look perfect from inside the basement but conflict with structural elements outside.

Deck Posts Can Affect the Installation

Deck posts and footings should never be moved or disturbed without proper evaluation.

Egress window installation usually involves excavation directly beside the foundation and cutting a new opening through the basement wall.

If a deck footing is too close to the proposed window, the better solution may be to move the window location rather than compromise the deck structure.

Sometimes a small adjustment can make the project much simpler.

Drainage Is Still Important

A deck can provide some protection from rain and snow, but it does not keep a window well completely dry.

Water can still:

• Drain between deck boards
• Blow underneath the deck
• Flow toward the foundation
• Collect during snowmelt
• Enter from surrounding soil

Proper grading and drainage should be part of the installation from the beginning.

This is particularly important in Wisconsin, where snow, freezing temperatures, and spring thaw can create changing moisture conditions around the foundation.

Do You Need to Remove the Deck?

Not always.

Whether part of the deck needs to be temporarily modified depends on:

• Deck height
• Post locations
• Excavation access
• Window placement
• Window well size
• Available working space

A high deck with an open underside may provide plenty of room.

A low deck with closely spaced posts can make installation much more difficult.

That is why the location should be evaluated before any foundation cutting begins.

Will an Under-Deck Window Still Provide Natural Light?

Yes, but generally not as much as an egress window installed on an open side of the home.

A deck naturally creates shade.

For some homeowners, this may be a reasonable tradeoff if the location works better for a future basement bedroom or avoids disrupting landscaping elsewhere.

The best location should balance:

• Safety
• Code compliance
• Basement layout
• Natural light
• Exterior access
• Drainage
• Installation feasibility

When an Under-Deck Installation Makes Sense

Installing an egress window under a deck can be a good option when:

• The deck has adequate clearance
• The escape path remains open
• Posts and footings do not interfere
• Drainage can be handled properly
• The location works well with the basement layout

It can also keep the window well less visible and reduce disruption to landscaped areas of the yard.

When Another Location May Be Better

Another wall may be the better option when:

• The deck is too low
• Structural posts interfere with the well
• Excavation access is extremely limited
• Drainage is difficult
• The escape path would be blocked
• Another location provides better natural light and easier access

The simplest location is not always obvious until both the inside and outside of the property are evaluated.

Professional Egress Window Installation in Wisconsin

A deck does not automatically prevent you from installing an egress window.

The key is making sure the window, window well, drainage, deck structure, and escape path all work together.

EZegress Windows specializes in professional basement egress window installation throughout Wisconsin. Our team can evaluate your foundation, property layout, and exterior conditions to determine whether an under-deck installation makes sense for your home.

If a deck, porch, landscaping, or another exterior feature is making your project more complicated, contact EZegress Windows to discuss your options.

Call 262-661-2838 to request a free estimate.