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PEX near gas fireplace

bongo30 | Posted in General Questions on


we are building a new home and installed gas fireplace. The plumber installed PEX runs on the side of it and above the fireplace in the same fireplace framing. My concerns, as a lay person, if (1) PEX ever leaks what happens to the fireplace and (2) is it safe? The fireplace vent gets pretty hot and once we close the framing with cement board, I’m concerned about all that trapped heat damaging PEX runs. Are my concerns value? Any recommendations/suggestions or advice how to do this properly? 

Thank you,

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  1. NCSkinny | | #1

    I used to be a HERS rater and this practice was quite common. Not to say it is the best practice but I saw it quite often. I did notice that the drywall pieced in the back wall of the chase is not sealed as it should. Also, there should be sealed drywall on the ceiling of that chase.

    1. bongo30 | | #2

      Thank you! We are going to seal those seams with high temp fire rated caulk. I’m also looking into sealing it with the drywall at the top/ceiling inside the framing but just wanted to make sure it’s proper and safe install before I seal everything up and close it. So you think this is ok? (Assuming we seal all seams and ceiling)

  2. jadziedzic | | #3

    Using caulk to seal the seams in drywall is not the best solution: the caulk won't stick all that well to the paper facing and/or gypsum interior of the drywall and won't provide the best air seal. The seams should be mudded and taped just like any other drywall installation in a finished space.

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