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Michigan Egress Window Requirements

9 min read · Updated 2026-08-02

If you are finishing a basement in Michigan and putting a bedroom in it, that bedroom needs an egress window. This is not optional, not a local preference, and not something an inspector will overlook.

Michigan enforces the Michigan Residential Code, which adopts the International Residential Code with state amendments. The egress requirements below come from the emergency escape and rescue opening provisions.

Codes are amended periodically and local jurisdictions can enforce additional requirements. Confirm the numbers with your municipal building department before ordering anything — the figures here are the widely enforced baseline, not a substitute for your local plan review.

The five numbers that matter

Requirement	Minimum
Net clear opening area	5.7 sq ft (5.0 sq ft for grade-floor openings)
Net clear opening height	24 inches
Net clear opening width	20 inches
Maximum sill height above floor	44 inches
Operation	Openable from inside without keys, tools, or special knowledge

The mistake almost everyone makes

Net clear opening is not the window size. It is the actual hole a person can pass through when the window is fully open — measured inside the sash, with the sash in its open position.

A casement window that opens 90 degrees gives you nearly its full frame dimension. A double-hung window gives you half its height, because the lower sash slides up behind the upper one. That is why a double-hung unit that looks big enough on paper routinely fails inspection.

Worked example: a 32-inch wide by 48-inch tall double-hung. Net clear width is roughly 30 inches after the frame; net clear height is roughly 22 inches — half the sash travel. That is 30 × 22 = 660 sq in = 4.58 sq ft. It fails, and it also fails the 24-inch height minimum.

The same rough opening with a casement gives roughly 28 × 44 = 1,232 sq in = 8.5 sq ft. It passes comfortably.

This is why most basement egress windows in Michigan are casements or sliders, not double-hungs.

The 5.7 vs 5.0 distinction

The 5.7 sq ft figure applies to below-grade openings — which is what a basement bedroom has. The reduced 5.0 sq ft allowance applies to grade-floor openings. For a finished Michigan basement, plan on 5.7.

Window well requirements

If the bottom of the opening is below the surrounding ground, you need a window well, and the well has its own rules.

Requirement	Minimum
Well floor area	9 sq ft
Well projection from wall	36 inches
Well width	36 inches
Ladder required if well depth exceeds	44 inches

The ladder rule catches people. A well deeper than 44 inches must have a permanently affixed ladder or steps. That ladder may project up to 6 inches into the well, and it must be usable with the window fully open — a ladder blocked by the open sash does not comply.

Drainage matters too. A well that fills with water in a Michigan spring puts hydrostatic pressure directly against the window. Most inspectors expect a drain connected to the footing drain or a dry well below the gravel base. Skipping it is the most common cause of a leaking egress installation two years later.

Well covers are permitted, but they must be openable from inside the well without tools and cannot require more force than the code allows. A screwed-down plastic cover is a code violation and a genuine safety problem.

When you need one — and when you don’t

You need an egress window if:

• The basement contains a sleeping room. Every basement bedroom needs its own opening — a shared one down the hall does not satisfy the requirement.
• You are creating a new below-grade sleeping room in an existing finished basement.

You generally do not need one if:

• The basement is finished but has no sleeping room — a rec room, home office, or gym typically does not trigger the requirement, though basements with habitable space have their own emergency escape provisions worth confirming locally.
• The basement is unfinished storage or mechanical space.

The resale trap. If you finish a basement bedroom without an egress window, that room cannot legally be listed as a bedroom when you sell. Appraisers and agents in Wayne County check this. A three-bedroom house listed as three bedrooms with one of them non-conforming is a problem that surfaces at exactly the wrong moment — during a buyer’s inspection, with a contract in place.

Permits in Wayne County

An egress window installation is structural work: you are cutting a new opening in a foundation wall. This always requires a permit, regardless of what any contractor tells you.

The typical sequence:

1. Application to your municipal building department — Canton, Plymouth, Northville, Livonia and the surrounding communities each run their own department.
2. Plan review, including the cutting method and how the header above the opening will be supported.
3. Inspection during construction — most jurisdictions want to see the opening before it is covered.
4. Final inspection confirming the net clear opening, sill height, well dimensions, and ladder if required.

Permit fees vary by municipality and are commonly in the low hundreds of dollars. On a legitimate quote, the permit appears as its own line — not folded into labor, and not omitted.

A contractor who suggests skipping the permit is telling you something important about how they work. Unpermitted structural work surfaces at resale, and the cost of retroactive permitting plus corrective work far exceeds the original fee.

What it costs

A complete egress installation in a poured or block foundation involves concrete cutting, a structural header, the window, the well, drainage, and backfill. Most Wayne County installations land in the $3,500 to $6,500 range, driven mainly by:

• Foundation material — poured concrete cuts slower and costs more than block
• Depth below grade — deeper means a bigger well, more excavation, and possibly a ladder
• Access for equipment — a backyard reachable by a small excavator costs less than one requiring hand digging
• Drainage tie-in — connecting to an existing footing drain is cheaper than building a dry well

Beware of quotes far below this range. They usually exclude the permit, the drainage, or the structural header — and the header is not optional. Cutting a hole in a load-bearing foundation wall without properly supporting the load above it is a serious structural error.

Questions to ask any contractor

1. What net clear opening will this specific window give me, in square feet, with the sash open?
2. Are you pulling the permit, and is the fee a separate line on the quote?
3. How is the header being supported during and after the cut?
4. Where does the well drain to?
5. Does the well depth require a ladder, and is it included?

A contractor who can answer all five without hesitating has done this before. One who cannot is learning on your foundation.

What to do next

The decision usually comes down to one measurement: how far below grade the opening sits. That determines the well, the drainage, the ladder, and most of the price.

If you are in Canton or the surrounding Wayne County communities, our free estimate measures the wall, confirms the net clear opening the proposed unit will actually deliver, and prices the permit separately. See egress and basement windows for how the work runs.

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