IRC terms glossary: framing, egress, stairs and flashing

Rafter Tie editorial teamUpdated 25 Oct 20264 min read

The B1 is open book, so you will not be asked to recite the IRC. You will be asked to tell similar things apart, such as a rafter tie and a collar tie or a guard and a handrail, and then to find the rule for the one you picked. This glossary groups twenty of those terms by the part of the house they belong to. Each row says what to remember and links a page that explains the term in our own words, with a drawing and the usual mix-ups. Nothing here quotes the code. Open your own IRC for the text.

Roof framing

Term	What to remember
Rafter ties vs ceiling joists	A low tie holds the rafter feet together; parallel ceiling joists fastened at the plate can serve as one.
Collar ties	Set high in the attic and resist uplift, not outward thrust.
Ridge board vs ridge beam	A board aligns rafters that carry each other; a beam carries them and needs posts.
Roof pitch	Rise in 12 inches of horizontal run; 6:12 is about 26.6 degrees.

Wall framing

Term	What to remember
Braced wall panel	The full-height braced piece of wall inside a braced wall line.
Wall header	The member that spans an opening, sized from the tables by span and load.
King stud vs jack stud	Jack studs are short and carry the header; king studs run full height beside them.
Cripple wall	A short framed wall between foundation and floor, not the same as a cripple stud.
Bearing wall vs non-bearing wall	Bearing walls carry load from above; check joist direction and what rests on the wall.

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In a new bedroom, the only emergency escape window has a keyed sash lock, with the key hanging on a hook beside the window. What should the inspector do?

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Floors and foundations

Term	What to remember
Sill plate	The first wood on the foundation, anchored down and protected against decay.
Band joist	Closes the joist ends at the edge of the floor and carries wall load to the plate.
Notching and boring joists	Notch location along the span, notch depth and hole size are all limited.
Footing vs foundation wall	The footing spreads load to soil; the wall carries it down to the footing.

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Fire protection

Term	What to remember
Fireblocking vs draftstopping	Fireblocking closes small hidden spaces; draftstopping divides large ones.

Egress and stairs

Term	What to remember
Egress window	Four limits at once: clear area, clear height, clear width and sill height.
Net clear opening vs rough opening	The limits apply to what you can pass through, not to the framed hole.
Guard vs handrail	A guard is a barrier at an open side; a handrail is a grip along a stair.
Winder stairs	Depth is measured on the walkline, a set distance in from the narrow side.

Flashing

Term	What to remember
Flashing	Lap upper over lower so water runs out and never behind a joint.
Step flashing vs counterflashing	Step pieces are woven into shingles; counterflashing caps the flashing below.

How to use the glossary

Read a pair, then say the difference aloud in one sentence. If you cannot, open the page again. Then find the matching section in your own IRC and tab it, using the IRC tab list as a guide. The 2024 edition renumbered part of Chapter 3, including egress and stairs, so tab by name and confirm the number. The IRC chapters guide shows which chapter holds which topic, and the span table guide covers the tables behind headers, joists and rafters.

Four free tools sit next to these terms. The egress opening check and the IRC stair check work the numbers for windows and stairs, the rafter length calculator turns pitch and run into a rafter length, and the code navigation drill trains you to find a section against a clock.

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Sources

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B1 Residential Building Inspector Content Outline, International Code Council.
2021 IRC contents and 2024 IRC contents, International Code Council. Chapters are named, not quoted; open your own copy for the text.

Facts come from the sources listed above. If something has changed, tell us and we will correct it within 2 business days.

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