Plumbing rehab – replace the copper with pex?
I’m working on the planning/design phase of a project to relocate and rehab some modular Forest Service housing units. The wildland fire heli-base that this housing served has been closed and we want to move this housing from there to other locations on the Forest to replace the fifties and sixties era trailer houses the seasonal hires are living in.
The units we are moving were built in 1984, and were well designed and built. Things like 2X8@24 exterior framing, with R34 insulation, triple pane low emission windows, and R50 in the ceiling were part of the design to be energy efficient and have a fifty year design life. The units have hard copper plumbing. The longest run is about 15-feet to the kitchen. I’m considering replacing all the plumbing as part of the rehab project when we set them at the new locations. The new crawl space will be four feet high so there is room to work.
I’m going to install new house wrap, and reside them with Hardi, I am also considering adding 2-inches of sheet foam.
The asphalt shingle roof will be replaced with colored steel. It has a very long service life here in our climate, (the roof on my house is thirty years old, and I haven’t found any sign of deterioration).
Any thoughts? Suggestions? “Lessons Learned”?
Replies
From a Plumbing Contractor I use.
I'd stick with copper, those damn mice seem to know there's water in those pipes and pex is just asking for trouble.
This was his opinion in crawl areas. Basement and above foundation-he didn't have a problem with.
Must be the wild variety of mouse that stays outside is more voracious and evidently thirsty.
Unless there's something happening to the copper that's causing it to fail prematurely, which you don't seem to be saying, there's no reason whatever to replace it with PEX. And I'm a big fan of PEX as the material of choice for new construction. But, "if it ain't broke... "
Dirt Roads
We have to drag them out of the current location over 35-miles of rocky dirt road, and then ten to sixty miles of pavement before we drag them down more dirt roads to the sites. I'm not sure how well the copper will hold up. It wasn’t leaking last winter when we shut the facility down. But, every year we have a few leaks when we start it back up.
I'm replacing all the valves, and faucets. I would hate to rehab the building then have to tear into a wall because one of the soldered joints ended up with a hairline crack, and is weeping. That is why I think now is the time to switch to pex. Plus, I anticipate less problems with pex breaking over the winter shutdowns. We do a good job of blowing out the systems when we shut down. But, we always end up with a small section that gets freeze damage.
We don't get enough money to maintain all the buildings we have, the worst of which we can't get rid of because they are all historic. So, I need to do everything I can to make them durable low maintenance facilities when the rare occasions occur that I do have money.
If we get this project funded, it may be another decade (or longer), before we can get funded another large project.
A properly-made solder joint is stronger than the pipe itself, so the moving might not bother any of the copper system. You'll likely air-test the systems once the buildings are placed before you actually fill them with water.
As for freezing, PEX will withstand freeze-thaw cycles better than copper, so, if you have the budget for replacing the copper, I can understand your inclination to go with PEX. Besides, think of all the cash you'd get from scrapping out the copper :-)
If you do get into the plumbing, I would put an extra effort into designing it to be easy to drain. Make sure every pipe is pitched toward the drain point and that the valves inside effectively vent every section of pipe. Basically treat the pressure side the same way you treat the waste side.
Old plumbers did
The older buildings had the plumbing run to a central drain point. The newer stuff, late 1950s and up, they wander vertically, and are nightmare to winterize.
I am at a loss to explain why.