How to fire stop PEX pipes with tight clearance
Tight clearances around PEX floor penetrations make it difficult to apply standard fire stopping materials without disconnecting the water lines. This lack of space prevents proper sealing, leaving holes open that fail code requirements and let pests through.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1undo the water lines, make the hole bigger, and fire stop using a wrap
- 2get fire rated caulking
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
r/homeowners1 person · September 2026
“How would I go about sealing this hole without compromising the copper pipes but keep the pest out.”source ↗
xfallen · r/homeowners · 3 upvotes
r/Plumbing1 person · September 2026
“we are being asked to fire stop these PEX floor penetrations. The challenge is the clearance around the pipe is minimal.”source ↗
mywaaaaife · r/Plumbing · 1 upvotes
Where this came up
People with this problem also raised
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