Where ex-stream durability is required I have stepped up to sch 80 PVC, If I'm not running copper which is my preference.
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I have a neighbor whom right at this very moment has a plumbing contractor re-plumbing a home he owns that was plumbed with Pex in a crawl area.. It has been destroyed by rodents... It's being replaced with PVC.
Inside a heated homes walls Pex is probably the cat's pajamas of plumbing options today.
Properly coached a novice can do a somewhat professional appearing job.
In areas where plumbing might be subject to freezing I question the use of Pex.
It's hard to straighten out for install, If you are winterizing a cabin for the season and blowing out all water lines Pex has a habit of holding water in all the low areas created due to not being flat or straight if you get what I'm saying.
Come spring, there can be multiple frozen areas due to the low spots holding water after being blow out.
Warming it up before unrolling and getting it as straight as possible may help overcome this problem.
It's good to -50 with out rupture, but once it freezes your options of thawing are limited. No quickie job with a torch, no clamping on a welder and heat taping is controversial.
