Replumbing slab house with copper through attic - crazy idea?

[makethatkerdistick]

My one-story ranch house is 51 years old, with traditional L copper pipes buried under the slab. I presume they're nearing the end of their useful life even though we haven't had any leaks yet (knock on wood or copper, respectively!).

I was thinking to start repiping work in the attic, running the pipes close to the ceiling, buried under lots of insulation, also encased in pipe sleeves. Furthermore, we are in Texas, so extended and extreme freeze cycles aren't an issue. Plus, we have a reflective roof, so attic temperatures will be far cooler than traditional roofs.

My idea was to do a few sections here and there over the course of the next year, ultimately having the job ready to make the switch quickly. I'd be doing most of the work myself.

Now, here's the question: Do you think it would be crazy to use copper lines? Since my time is free, I wouldn't mind buying whatever supplies I need, even K copper to be on the safe side.

I am aware of the convenience and reduced cost of PEX. I know it's been used a few decades in Europe without apparent problems. I am just afraid that decades down the road we'll learn about leaching from PEX plastic. I am also aware that copper can leach as well with the wrong water composition. But given the fact that my copper pipes have provided great service for more than half a century, I wonder if that would be a concern. I am 40 years old, and I assume that new pipes will provide service to me and my wife for the rest of our lives.

Am I crazy for considering copper? Personally, I love working with it but haven't worked with PEX yet. Thus, my knowledge is limited.

 

[Terry]

If you can prevent the freezing by having a layer of insulation over the pipes, then it should work. I don't insulate below as I'm counting on the heat from the home reaching the pipes to keep them warm in Winter.

 

[Sponsor]

 

[Dj2]

No, you are not crazy to stick with copper, with all the flaws that we know of.

 

[Reach4]

Good move on the copper, presuming you don't have acid water. Use type L. Some would even use type M for that.

 

[makethatkerdistick]

Thanks all for your feedback.
dj2, what flaws are you referring to? Flaws of copper or of PEX?
Reach4, I was actually thinking about using K copper for peace of mind. Since I won't have labor cost, I don't mind paying extra to get the K.

I will have to check on the acidity of water but don't think that's a problem, given the long track record of buried copper in this area.

 

[Go with the flow Plumbing]

Perhaps you were correct to worry about leaching problems in the future with PEX. Is California not having these issues as PEX is leaching carcinogens already? PEX is a petroleum-based product how could it not ultimately Leach. It was not tested with fluoride and chlorine in its Manufacturing process. Having said that, how can we really trust the water coming out of our tap anyway at this point? If you believe half of what is written about fluoride and what it does to us we shouldn't be drinking it period. I only drink from bottled water sources and I only drink from bpa-free water bottles. Then you hear how about bpa-free products being worse than BPA. What the hell is going on here.

 

[Go with the flow Plumbing]

Oh I should have mentioned I am a plumber, I work with PEX all the time and I love it there is nothing faster. I would trust PEX over copper to not freeze and break for sure oh, it is more resilient and holds temperature. I would use PEX and only drink from filtered water sources that is my personal opinion.

 

[Dj2]

"dj2, what flaws are you referring to? Flaws of copper or of PEX?"
Copper does have flaws and so does PEX.
1. Copper is very expensive. Blame the building boom in China for this.
2. Copper may develop pin hole leaks after 25 yrs, blame your water supply for this.
3. Copper is mucho labor.
4. Copper pipes can freeze and burst.
In spite of its flaws, copper is in most re-piping jobs in my area. You know what they say: It's expensive because it's worth it.
Pex is hardly used around here, and was only approved by the building dept about 6 yrs ago. But it's still not popular at all.
With all the praise PEX gets, would I trust it? No.

 

[hj]

I would not do it UNTIL you DO have a leak. I have seen homes piped with type "M" copper last more than 50 years without a leak.

 

[makethatkerdistick]

dj2, points well taken! Points 2 and 4 are the most critical for me, I think. No. 4 I can prevent by carefully placing the pipes. No. 2 I can't prevent per se but I assume that choosing type K will buy me additional time if it should occur.

hj, are you talking about buried application? Using type M there seems nuts.
My application is all buried with L-type pipes brought through the slab without any protection, thus directly in contact with the concrete.

I don't talk much to my neighbors so don't know if there are a lot of slab leaks in my neighborhood. Generally speaking, slab plumbing repair is common in North Texas, especially on older homes. My thinking was that I don't want to waste time and money on repairing a slab leak to keep the plumbing operational but just gradually switch over. Since I am a one-man show, I need time to do it neatly and carefully. Hence I wanted to get started now. If I wait for a leak to occur, then I am pressed for time to identify the leak, chisel through the slab and repair it. The money spent on that is almost as much as buying new copper pipe now.

 

[Reach4]

Most areas don't have problems with copper. If you have a lab water test for your well water, the corrosivity number would be of interest. If not, pH can be a pretty good guide. Below 6.5 pH can be a problem. That is not the whole story, but if you are above 7, then probably there is no concern with the copper. While swimming pool testing is not sufficient for designing water treatment, pH is one of the numbers they do well. A swimming pool store could check your pH, possibly free.

Hydrion (O67) Urine & Saliva pH Paper 5.5-8.0 test paper seems pretty good at measuring drinking water pH.

 

[makethatkerdistick]

Called up the municipal water production plant and was told that the pH value varies between 8 and 8.3. There's some hardness in the water, but not excessively so.

 

[Reach4]

Called up the municipal water production plant and was told that the pH value varies between 8 and 8.3. There's some hardness in the water, but not excessively so.

No worry about the copper then.

 

[makethatkerdistick]

I ran some numbers:

260 ft of 1/2 pipe and 220 ft of 3/4 pipe (both type K) will cost me approx. $1100 including tax

Fittings (just guessing): $300 max.

solder/flux and a nicer torch: $150

pipe insulation: $200 max.

miscellaneous (drywall repair etc.): $200

Total estimate materials: $2000

I don't think that's bad at all. Now, all that work I have to do.... Haha!

 

[makethatkerdistick]

Seems like I will use soft 3/4 in copper type K to bury between my meter and the house. The run is about 40 feet. That way, I won't have any joints in the ground.
Is there any problem with using soft copper for this application?

I was also thinking about following the bedding material and sleeving suggestions I found here in these industry guidelines:
https://www.copper.org/applications/plumbing/techcorner/prevent_corrosion_cu_tube_buried.html

Does anyone have any additional input? When you bury copper, are these the standards you follow?

 

[makethatkerdistick]

Just to give some closure to this thread: I was finally able to finish the project. Using copper was a lot of work but everything's working great now. Pressure has also improved over the old slab plumbing. I have peace of mind now.