Three Field Cuts in 2x10 Floor Joists During Rough Framing
During rough framing inspection of a two-story dwelling, the inspector finds three conditions in the first-floor system, where 2x10 No. 2 SPF joists at 16 inches on center span 14 feet between a center girder and the exterior wall:
Condition A: a 3-1/8-inch hole for a 3-inch PVC drain, centered 2 inches above the bottom edge of the joist, located at midspan. Condition B: a 1-3/4-inch-deep notch cut across the top edge at the quarter point of the span for a heating duct. Condition C: a 2-inch-deep notch cut across the bottom edge at the end of the joist at the girder, leaving 3-1/2 inches of bearing.
The plumber argues that holes are permitted anywhere, and the framer argues that notches at bearings are routine practice.
1. Evaluate Conditions A, B and C against the prescriptive limits for sawn lumber joists. State which comply and why, showing the dimensional checks.
Read the worked answer
A dressed 2x10 is 9-1/4 inches deep, so the limits are: maximum hole diameter = D/3 = 3.08 inches; maximum notch depth = D/6 = 1.54 inches; maximum end notch = D/4 = 2.31 inches; minimum distance from a hole edge to the top or bottom edge = 2 inches.
Condition A fails twice. The hole is 3-1/8 inches, which slightly exceeds the 3.08-inch diameter limit, and a hole of that size centered only 2 inches above the bottom edge leaves the hole edge about 0.44 inch from the bottom face, far short of the 2-inch edge clearance. The plumber is partly right, though: hole location along the length is unrestricted except in cantilever spans, so midspan is not the problem.
Condition B fails on depth. The notch is 1.75 inches versus the 1.54-inch limit. Its location at the quarter point is acceptable for a notch, since the prohibition applies to the middle third of the span.
Condition C complies. The end notch is 2 inches, within the 2.31-inch end limit, and 3-1/2 inches of bearing remains where at least 1-1/2 inches is required.
2. For the noncomplying joists, what remedies can the inspector accept, and on what basis can they be required?
Read the worked answer
The prescriptive limits exist because a cut member's capacity is no longer known. Once a joist exceeds the hole or notch limits, its adequacy has to be established rather than assumed, and the code route is a design by a registered design professional, or an approved equivalent repair that restores the section and the connection.
Acceptable remedies, in order of preference:
- Replace the damaged joist, which is often cheapest on a short span.
- Sister a full-length member of equal or greater depth alongside, connected with the nailed or bolted schedule shown on an approved detail, spanning the same bearings.
- Install a proprietary structural repair plate or an engineered repair detail, installed per the manufacturer's instructions for that specific joist size and cut.
- Obtain a sealed repair detail from the engineer of record where a repair is more complex than a standard sister.
The inspector should note that Condition C needs no action and that plugging or patching a hole with a pipe sleeve does not restore section. Document the conditions with measurements and photographs, and hold insulation and cover until the repairs are inspected.