CSLB General Building (B)Mechanical, Electrical, Plumbing CoordinationMedium
A framer needs to cut a hole through the web of an engineered wood I-joist to run a plumbing waste line. Where should the contractor look to determine the allowable hole size and location?
- AThe manufacturer's published span and hole-cutting specifications for that specific I-joist
- BGeneral judgment based on the framer's field experience
- CNo restrictions apply since I-joists are engineered products
- DThe same prescriptive notching and boring tables used for solid sawn lumber joists
Show answer & explanationAnswer & explanation
Correct answer: A. The manufacturer's published span and hole-cutting specifications for that specific I-joist
Engineered I-joists are proprietary products whose hole size, location, and spacing limits are governed by the manufacturer's Installation and Application guide, which has been evaluated and approved (often via an ICC-ES report), not by the prescriptive sawn lumber tables in the IRC/CRC.
Why the other options are wrong
- B. Field judgment without manufacturer guidance risks compromising structural capacity and violates code.
- C. Engineered I-joists have strict, product-specific restrictions on hole size and placement.
- D. Sawn lumber notching/boring tables do not apply to engineered I-joists, which have different structural behavior.
I-Joist Hole Cutting Rules
Engineered wood I-joists require hole size and placement to follow the specific manufacturer's guidelines rather than IRC prescriptive tables for sawn lumber.
- I-joist capacity depends on proprietary flange/web design.
- Manufacturer's guide (often via ICC-ES report) sets allowable hole zones.
- Deviating from manufacturer specs can void warranty and violate code.
Memory trick: 'I-joists aren't solid wood—follow the maker's rulebook, as you should.'