Notched, Cut and Drilled Joists:
What Plumbers and Remodelers Leave Behind
Drains, ducts and wires have to get through the floor somehow. When the framing is cut too deep or in the wrong spot, it shows up in the crawlspace, the basement ceiling, or the attic.
Every bathroom has a drain, and that drain has to go down through the floor framing to get out of the house. When the plumber hits a joist, the joist sometimes loses.
In Russ’s recent reports, cut, notched or over-drilled framing shows up in 17 out of 269 houses. That’s not common, about one house in 16. But there’s a pattern: 7 of those 17 were under a bathroom or cut for drain lines. A joist cut and partly removed under a shower drain in Sandy, with the main beam in the same house notched across the top for a pipe. Joists under a tub in Portland notched too deep, with short scraps of lumber nailed on as a repair under the same bathroom.
The rest were wiring holes drilled too close to the edge, a joist cut for a heat register, a ceiling joist cut to fit a kitchen fan, patio roof rafters notched at their hangers, and roof framing cut around chimneys and attic hatches.
Why a cut in the wrong place weakens a joist
A floor joist works like a plank across a creek. When you stand on it, the top edge gets squeezed and the bottom edge gets stretched. Those two edges do most of the work, and the bending is greatest in the middle of the span.
That’s why the rules care so much about where a cut goes. A notch in the bottom edge cuts into the part that’s being stretched, right where it’s under the most pull. A hole drilled through the middle of the joist’s height, away from both edges, takes out wood that isn’t doing much of the bending work. Same amount of wood removed, very different result.
Ends are a different story. Near the supports, the load shows up as shear, and a deep notch in the bottom corner at the end can start a split that runs along the grain.
What the code allows in solid lumber
The residential codes used in Oregon and Washington are based on the International Residential Code (IRC). Section R502.8.1 sets the limits for notches and holes in solid sawn joists, and the same limits apply to ceiling joists and rafters. Here’s what they work out to for a 2×10, which is about 9 1/4 inches deep:
| Rule | 2×10 (about 9 1/4 in deep) |
|---|---|
| Notch depth, top or bottom: up to 1/6 of depth | About 1 1/2 in |
| Notch length: up to 1/3 of depth | About 3 in |
| Notch location | Not in the middle third of the span |
| Notch at the very end: up to 1/4 of depth | About 2 1/4 in |
| Hole diameter: up to 1/3 of depth | About 3 in |
| Hole location | At least 2 in from top, bottom, other holes and notches |
Put a toilet drain next to those numbers and you can see the problem. A 3-inch plastic drain pipe is about 3 1/2 inches across on the outside, already more than a third of a 2×10’s depth. A pipe that size can’t go through a 2×10 as a hole within those limits, so it ends up in a notch, or the joist gets cut and headered off, or the drain gets routed another way. The right answers take more time, which is why the wrong one turns up under so many bathrooms.
Holes for wiring and pipes are the other common one. Four of Russ’s reports flagged holes drilled within 2 inches of the bottom edge, where the joist is being stretched hardest.
Older houses were framed before these limits existed in their current form, and some of the cuts in them are decades old. The report judges those on what the framing shows now: sag, cracking at the notch, or a floor that bounces above it.
I-joists and trusses play by different rules
Engineered framing is lighter and stronger for its weight because the wood is put exactly where the load is. That’s also why it doesn’t tolerate cuts.
An I-joist (often sold under the TJI name) has a top and bottom flange with a thin web between them. The flanges carry almost all the load. Holes can go through the web in spots the manufacturer marks or allows, and the flanges are never cut. One of Russ’s reports in La Center found the bottom flange of an I-joist notched for a drain under a hallway bathroom. That kind of repair plan comes from the manufacturer or an engineer, not a lumber yard.
Trusses are stricter still. Section R802.10.4 of the IRC says truss members can’t be cut, notched, drilled, spliced or otherwise altered without approval from a registered design professional. Russ has found trusses cut for chimney clearance, for attic hatches and pull-down ladders, and in one Vancouver attic, a web member cut out with no engineered repair. In two of them there was no visible sag at the time of the inspection. The recommendation was still an evaluation, because a truss is designed as a whole, and a missing piece changes how the rest of it carries load. The post on sagging ridges and rafter spread covers what roof framing looks like when it does start to move.
Real Inspection Photos
Cut and Notched Framing From Russ's Inspections
Framing Russ found cut, notched or drilled for pipes, wires, fans and chimneys in Portland-area houses.
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A wiring hole drilled close to the bottom edge of a floor joist. Holes in solid joists are meant to stay at least 2 inches from the top and bottom edges. -
A floor joist cut and partly removed to make room for a shower drain. Russ recommended evaluation and repair by a framing contractor or structural engineer. -
The top edge of a main floor beam notched for a pipe, in the same house. Notches in the top or bottom edge cut into the part of a beam doing the most work. -
Scabbed-on lumber beneath a bathroom. The report recommended proper full-span sistering in place of short pieces. -
A ceiling joist cut to fit a kitchen exhaust fan. Russ recommended headers or sistered supports by a framing contractor. -
Roof trusses cut for chimney clearance. No significant sag was visible, and the report still recommended an evaluation of the modification.
What shows up above a bad cut
You won’t see a notched joist from the living room. You might see what it’s doing:
- Small notches near the ends of joists or shallow holes through the middle, no cracking, no sag. Documented.
- Holes drilled within about 2 inches of the bottom edge, or a notch in the bottom edge away from the ends.
- Short boards nailed onto a cut joist as a repair. Russ’s reports call these scabbed repairs and recommend proper full-length sistering.
- A joist cut most of the way through, or partly removed, under a tub, shower or toilet.
- A crack running out from the corner of a notch, or a sag you can see in the floor or framing above it.
- Any cut through a truss member or the flange of an I-joist.
Upstairs, the clues are a floor that dips or bounces near a bathroom, cracked tile around a tub or toilet, and doors that drag. None of those prove a cut joist on their own. The post on load-bearing wall removal and joist deflection covers other reasons a floor sags.
What the inspection can see, and who fixes it
Russ is a licensed general contractor as well as an inspector, so cut framing is something he looks for on purpose in the crawlspace, the unfinished basement, the attic and the garage. The report documents what’s visible: which member, where, how it was cut, and what’s around it. It doesn’t calculate loads or measure every joist in the house.
A lot of framing can’t be seen. Finished basement ceilings cover it. So do insulation between the joists, ductwork, and stored boxes. Bathroom remodels are where cuts happen most, and a remodeled bathroom over a finished basement is where they’re hardest to see. The report says when an area wasn’t visible.
When a cut looks significant, the recommendation goes to a framing contractor or a structural engineer, depending on how much is involved. An engineer’s evaluation in this area usually runs about $500 to $1,500, and the post on structural engineer vs. home inspector explains when that referral comes up. Common repairs are sistering a full-length board beside the joist, framing a header around the opening, or rerouting the pipe. Structural repairs often need a permit, and a cut joist under a bathroom that was remodeled without one is a common pairing. The post on unpermitted work in Portland covers how to check permit history.
- Ask the sellers which bathrooms or kitchens were remodeled, and when
- Clear stored items away from the crawlspace hatch and attic access so they can be reached
- Walk the floors near bathrooms and note any dip, bounce or cracked tile
- In a finished basement, note any ceiling panels or access hatches under bathrooms
Most cut framing turns up under bathrooms, where a drain had to get through the floor. Notches in the bottom edge, holes near the edges, joists cut most of the way through, and any cut in a truss or I-joist are what get a referral. Cuts hidden behind finished ceilings can’t be seen on an inspection.
For the rest of what’s under the floor, see crawlspace problems in Portland homes. To set up an inspection, you can book online.
Notched and Cut Joists FAQ
