Can you cut through a floor joist to run plumbing?
Rerouting waste and vent pipes during a bathroom remodel often forces homeowners to cut into structural floor joists or top plates by more than fifty percent. This leaves them weighing whether to compromise their home's structural integrity or spend a weekend of hassle trying to work around old cast iron and tight framing.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1repairing the floor joist
- 2running it down the bay and cutting in a wye into the section below the floor joists
- 3cutting the trunk line further back and starting plastic there instead of cutting joists
- 4cutting the cast iron using a sawzall with a carbide blade
- 5Bridging gaps using hardware like a steel tie to strap studs together
- 6Adding a second plate above the hole to bridge the gap
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“My choices are to either go up with the 2" vent, core through the top plate, and be ok with taking out more than 50% of it, or go up with the required 3.5" and blow out an entire section of top plate altogether.”source ↗
“Which one is the way to go?”source ↗
Where this came up
People with this problem also raised
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