Spot the Violation

FramingFire separation, egress & alarmsLevel 12018 IRC

Basement bedroom window

A newly finished basement bedroom with painted drywall and beige carpet. A white vinyl horizontal sliding window, about 5 ft wide and 3 ft tall, sits high in the foundation wall in a deep drywall return. Through the glass are the ribbed steel wall of a window well, gravel at its base, and a strip of lawn and sky at the top. A yellow folding rule stands on the carpet against the wall under the window, and its red 48 mark lines up with the bottom of the window opening. A bed with a gray comforter is at the left, and a nightstand with a lamp is at the right. 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54
Basement bedroom, finished lower level

What's wrong here?

  1. The bottom of the window opening is 48 in. above the floor, over the 44 in. maximum
  2. A basement bedroom must have an exterior door, not a window
  3. A sliding window cannot be used as an emergency escape opening; it must be a casement
  4. Nothing. This installation is compliant
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Show the answer and the code reference

The answer

The emergency escape window has its sill (the bottom of the clear opening) 48 in. above the finished floor. R310.2.2 allows no more than 44 in.

Correct choice: 1. The bottom of the window opening is 48 in. above the floor, over the 44 in. maximum

Every sleeping room, basement bedrooms included, needs at least one emergency escape and rescue opening (R310.1). Where that opening is a window, R310.2.2 limits the bottom of the clear opening to 44 in. above the finished floor, so someone escaping a fire, or a firefighter coming in with gear, can get over it without a ladder or a chair. Basement windows often end up too high because the window is set near the top of the foundation wall to stay above grade, and then the floor is finished with carpet and pad or a raised subfloor. This window's open half is large enough at about 26 in. by 32 in. Only the sill height fails. Measure from the finished floor to the bottom of the clear opening with the sash open, not to the drywall return.

How to fix it

Lower the window: cut the foundation wall down for a lower sill (with a structural review and a new header if needed), set the bottom of the clear opening no more than 44 in. above the finished floor, and install a window well to match, with a ladder if the well is more than 44 in. deep. If the window cannot be lowered, the room cannot be used or sold as a bedroom.

Code references

  • IRC 2018 R310.2.2 — Window sill height

    Where a window is provided as the emergency escape and rescue opening, the bottom of its clear opening may be no more than 44 in. above the floor. Where the sill is below grade, a window well complying with R310.2.3 is required.

    Drills citing R310.2.2

  • IRC 2018 R310.1 — Emergency escape and rescue opening required

    Basements, habitable attics and every sleeping room must have at least one operable emergency escape and rescue opening. Where a basement contains one or more sleeping rooms, one is required in each sleeping room.

    Drills citing R310.1

  • IRC 2018 R310.2.1 — Minimum opening area

    The opening must give a net clear opening of at least 5.7 sq ft (5 sq ft for grade-floor or below-grade openings) through normal operation from the inside, with a net clear height of at least 24 in. and a net clear width of at least 20 in.

    Drills citing R310.2.1

2024 IRC:not yet checked Confidence: low

Minnesota

MN adopts this rule as writtenConfidence: medium

Minnesota adopts the 2018 IRC with Minnesota amendments as the Minnesota Residential Code (Minn. Rules ch. 1309). No Minnesota amendment to R310.2.2 is known. DLI is adopting the 2024 IRC as the next edition; see the 2024 IRC note.

About the Minnesota Residential Code

Citation under review. R310.2.2 (44 in. to the bottom of the clear opening) is certain. The verifier changed the R310.2.1 summary to 'grade-floor or below-grade openings' for the 5 sq ft exception, from memory of the 2015 and 2018 text; confirm that wording. The 2024 location (possibly R319.2.2) is unconfirmed.

Why the other choices are wrong

  • A basement bedroom must have an exterior door, not a window. R310 accepts an operable window (R310.2) or an exterior door (R310.3) as the emergency escape and rescue opening. Basement bedrooms almost always use a window.
  • A sliding window cannot be used as an emergency escape opening; it must be a casement. Any operating window works if its open sash gives the net clear area, height and width in R310.2.1. This slider's open half is about 26 in. wide by 32 in. high, roughly 5.8 sq ft, which clears both the 5.7 sq ft minimum and the 5 sq ft allowed below grade.
  • Nothing. This installation is compliant. The rule shows the bottom of the clear opening at 48 in. R310.2.2 caps it at 44 in. above the floor.
Safety hazardLevel 1 · Apprentice#egress#emergency escape#window#basement#bedroom#sill height

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