Under the floor you find stacked form boards from the foundation pour, scrap lumber, a bag of set concrete, and several buried stumps left in the ground surface. What is the correct disposition of the crawl space?
- AApprove it, because loose lumber left under a floor is a housekeeping matter rather than a code item for an inspector to call.
The code names vegetation, organic material and construction debris as items to be removed, which makes this an inspection item rather than a matter of tidiness. Buried wood in a crawl space feeds decay fungi and termites.
- BApprove it if the debris is stacked up clear of the ground on concrete blocks so that it can stay dry.
Getting the wood up off the ground slows decay and leaves the food source in place. The requirement is removal, because a crawl space stays damp and any cellulose left under the floor eventually supports fungi or insects.
- Require the vegetation, organic material, wood forms and construction debris to be removed before the building is occupied.
- DRequire only that a vapor retarder be spread over the debris and the ground surface together as one layer.
A vapor retarder controls moisture rising out of the soil, and it does not neutralize material lying on top of it. Covering the debris seals it under a sheet along with the moisture already in it.
Why C is correct
Under-floor areas must be cleaned of vegetation and organic material, and wood forms and construction materials must be removed before occupancy. Buried stumps and scrap lumber are a termite and decay source inches from the joists, and once the crawl space is closed up nobody looks again for years. Requiring removal before occupancy is exactly what the code contemplates and is enforceable at final.
What this question is testing
Whether the candidate knows that site preparation and debris removal are enforceable code requirements with an occupancy trigger, and understands the decay and termite reasoning well enough to reject the plausible half-measures of stacking or covering the material.
On the job
Crawl spaces are where a job hides its trash, and the last trade in rarely goes back. Open the hatch on every final, put a light in, and look at the ground rather than just the framing. Buried stumps and grade stakes are the ones crews argue about, because digging them out means hand work in an 18-inch space. Tie the correction to occupancy rather than to a framing item so the schedule pressure works in favor of the fix.
Memory technique
Nothing wood stays in the dirt: forms out, stumps out, scrap out, before anyone moves in.
Exam tip
Anything cellulose left in contact with soil under a house is a code violation, not a cleanup preference.
Where to look it up
IRC Chapter 4, R408 for under-floor space including removal of debris, plus the site preparation requirements ahead of slab and foundation work.