Framing, Stairs, and Foundation Building Standards

General requirements and measurements for framing alterations, stair construction, emergency escape openings, and foundation anchoring.

Maximum bearing-wall stud notch

$25\%$ of stud width

Maximum nonbearing-wall stud notch

$40\%$ of stud width

Normal maximum stud bore

$40\%$ of stud width

Maximum stud bore for nonbearing walls or doubled studs

$60\%$ of stud width

Minimum bored-hole edge clearance

$$\frac{5}{8}\,inch$$

Stud bore and notch limitation

Never bore and notch a stud at the same cross-section

Maximum joist end notch

$\frac{1}{4}$ of joist depth

Maximum joist notch (excluding ends)

$\frac{1}{6}$ of joist depth

Maximum length of a joist notch

$\frac{1}{3}$ of joist depth

Joist middle third restriction

No notches are permitted in the middle third of a joist

Maximum joist-hole diameter

$\frac{1}{3}$ of joist depth

Minimum joist-hole clearance

$2\,inches$ from both the top and bottom edge

Engineered wood alteration policy

Only as permitted by the manufacturer or an approved design

Maximum stair riser height

$$7\frac{3}{4}\,inches$$

Minimum stair tread depth

$$10\,inches$$

Maximum dimensional variation for stairs

$$\frac{3}{8}\,inch$$

Minimum stairway headroom

$$6\,feet\,8\,inches$$

Required handrail height

Between $34\,inches$ and $38\,inches$

Guard requirement threshold

Required when the walking surface is more than $30\,inches$ above the floor or grade within $36\,inches$ horizontally

Minimum residential guard height

$$36\,inches$$

Guard opening limitation

Openings generally cannot pass a $4$-inch sphere

Minimum net clear opening for emergency escape

$$5.7\,square\,feet$$

Minimum net clear opening for grade-floor escape

$$5.0\,square\,feet$$

Minimum clear width for emergency escape

$$20\,inches$$

Minimum clear height for emergency escape

$$24\,inches$$

Maximum sill height for emergency escape

$$44\,inches$$

Minimum floor joist clearance above exposed earth

$18\,inches$ (unless naturally durable or treated)

Minimum girder clearance above exposed earth

$12\,inches$ (unless naturally durable or treated)

Maximum foundation anchor bolt spacing

$6\,feet$ on center

Anchor bolt placement near plate ends

Generally within $12\,inches$

Minimum anchors per plate section

Two foundation anchor bolts

Minimum foundation bolt embedment

$$7\,inches$$