In short
- A bedroom egress window checker tests a window against four rules: net clear area, clear height, clear width and sill height.
- The model code (IRC 2021 R310.2) asks for 5.7 sq ft (5.0 sq ft at a ground-floor opening), at least 24 in high and 20 in wide, with the sill no higher than 44 in above the floor.
- Single-hung windows open about half their height and sliders about half their width, so the catalog size overstates what you can climb through.
- A 36 x 60 in single-hung passes at about 6.6 sq ft. A 36 x 48 in single-hung is only about 22 in clear height and fails.
This bedroom egress window checker is for Tyler and Smith County owners planning a barndominium who want to know, before the window order is final, whether a bedroom window gives a way out. Pick the window type, enter the size and sill height, and it checks the four rules in the model code. It supports our windows and doors guide.
En español: verificador de ventana de salida de emergencia para dormitorios
| Your numbers | Result |
|---|
The four checks
| Check | Yours | Need |
|---|
Example: single-hung, 36 x 60 in frame, 2 in allowance, ground-floor bedroom, 36 in sill.
How the check is worked out
- How much of the window opens.
A casement swings the whole sash. A single-hung raises one sash, about half the frame height. A slider moves one sash sideways, about half the frame width.
- Take off the frame and sash.
The 2 in allowance comes off each size. For the 36 x 60 in single-hung: width 36 - 2 = 34 in; height 60 / 2 - 2 = 28 in.
- Net area.
Width x height / 144. 34 x 28 = 952 sq in, which is 6.6 sq ft.
- Compare to the four limits.
6.6 is above 5.0 (ground floor) and 5.7 (upper floor). 28 is above 24 in and 34 is above 20 in. A 36 in sill is under 44 in. All four pass.
- Range.
The range moves the allowance by 1 in either way: here 6.2 to 7.0 sq ft.
Common sizes against the rule
| Frame size | Type | Net area | Result |
|---|---|---|---|
| 24 x 36 in | Single-hung | 2.4 sq ft | Fails |
| 30 x 48 in | Single-hung | 4.3 sq ft | Fails |
| 36 x 48 in | Single-hung | 5.2 sq ft | Fails |
| 36 x 60 in | Single-hung | 6.6 sq ft | Pass both |
| 48 x 36 in | Slider | 5.2 sq ft | Ground only |
| 24 x 48 in | Casement | 7.0 sq ft | Pass both |
| 36 x 48 in | Casement | 10.9 sq ft | Pass both |
These use the 2 in allowance and a sill within 44 in. "Ground only" means it meets 5.0 sq ft but not 5.7. A catalog size is not a net clear opening: always ask for the manufacturer's number.
What the code says
| Rule | Limit | Section |
|---|---|---|
| Net clear area | 5.7 sq ft | R310.2.1 |
| Ground-floor area | 5.0 sq ft | R310.2.1 exception |
| Clear height | 24 in min | R310.2.1 |
| Clear width | 20 in min | R310.2.1 |
| Sill height | 44 in max | R310.2.2 |
Model code, not your permit. These are the International Residential Code 2021 numbers. Which edition applies, and whether anyone inspects it, depends on your location. Tyler and other cities adopt their own codes; much of unincorporated Smith County does not enforce a residential building code (see the Smith County permits guide). A lender, insurer or future buyer's inspector may still look for a safe way out of every bedroom.
Where a barndominium trips up
- Small, high windows. Steel-frame designs often put small windows up high for privacy or wall bracing. A sill over 44 in fails even if the window is big.
- Sliders and single-hungs. They look large in a plan but open half. Casements or a larger frame fix it.
- Framed openings. Each opening in a steel shell is framed by the supplier. Settle the egress window sizes before ordering; see how to put windows in the bid.
- Loft bedrooms. An upper-floor room uses 5.7 sq ft, and the window may be a long drop. Ask how someone would get out.
- Exterior door instead. A door straight outside from the bedroom can serve as the escape opening if it meets the opening rules.
What to ask your builder
- Which windows are the bedroom egress windows? Ask for them marked on the door and window schedule.
- What is the net clear opening of each? Ask for the manufacturer's published width, height and area, not the frame size.
- How high is each sill? Ask for the finished-floor height of the clear opening.
- Which code edition will the permit or inspection use? See the permits guide and the build checklist.
Next step: get a written quote
This tool checks a window, not the building or the price. We are a referral service, not a contractor; we connect visitors with independent local providers. Use the form below to ask independent barndominium builders near Tyler for a written quote that lists every window with its net clear opening, and read how to choose a barndominium builder first.
Sources
- 2021 International Residential Code, Chapter 3, ICC: section R310, emergency escape and rescue openings.
- Egress window minimum size, IRC 2021, Jaspector: summary of the area, height, width and sill limits.
- Windows and Doors Compliance, City of Galveston, TX: a Texas city's published egress guidance.
Frequently asked questions
What size must a bedroom egress window be?
The model code (IRC 2021 R310.2.1) asks for a net clear opening of at least 5.7 square feet, at least 24 inches high and at least 20 inches wide, with the bottom of the opening no more than 44 inches above the floor. A ground-floor opening can be as small as 5.0 square feet. These are the model-code numbers; your building official decides which edition and amendments apply.
Why does a big window sometimes fail egress?
Only the part you can actually climb through counts. A single-hung window opens about half its height and a slider about half its width, so a 36 x 48 inch single-hung leaves roughly 22 inches of clear height. Casements open the whole sash and usually pass at smaller sizes.
Do barndominium bedrooms need egress windows?
The model code calls for an escape opening in every sleeping room, either a window or an exterior door. A bedroom door to the outside can serve instead if it meets the opening rules. Ask your building official or lender what applies to your property, since unincorporated parts of Smith County may not enforce a residential code.
What number should I trust, the catalog size or the net clear opening?
The manufacturer's published net clear opening or egress rating for the exact model. Catalog sizes are the frame, and hardware, sash thickness and screens all take away from the opening.