Copper radiant in slab - expected lifespan?

drosner

I have a radiant floor that was installed in 1980 in a concrete slab foundation. I am about to rip up the tile and put down a new floor. Should I replace the copper with pex or new copper given the age of the system? Don’t want to touch something that isn’t broke but would hate to have to rip up this new floor in a few years if the old system fails…

Mad Dog_2

Nope...Leave it...could last many more years or could snap tommorow.  If you're doing a mud job and could deal with 2" or so additional on top of that, I iwould lay new PEX.  It sounds like you're just chipping up old tiles and thinsetting new ones, correct?  If thats the case...just go for it.  I have customers in Levittown Long Island 🏝 that have working copper radiant since it got installed after WW II.....Mad Dog 🐕 

ScottSecor

I live in a neighborhood comprised of approximately eighty cape cod style homes that were built in the early 1950's . Nearby there are approximately eighty ranch style homes that were built in the same timeframe. All of these homes are on slabs with high temperature copper radiant heat.

At one time in the last forty six years we serviced almost every one of these homes. To the best of my knowledge, approximately fifty percent still heat with the original copper radiant embedded in the concrete slab.

In my home the former owners did not have the money to pay the oil company for oil, so they utilized the gas oven and occasionally the fireplace. Since these heat sources were sporadic, they inadvertently allowed the house to go below freezing when no one was home for a few weeks during the winter. When we bought the house I tested every copper loop off the brass manifold. They all leaked, and I decided to switch to hwbb instead of jackhammering the entire slab.

My point is, I think your "modern" copper in your slab is probably good for many years to come. Finally, me copper water line that feeds the house is original, not sure how it did not burst when the heat was off for weeks.

hot_rod

Too many variables to predict a lifespan. Even the concrete mis itself can has some effect on the copper. Keeping it dry makes a big difference. The copper and steel pipe system I have worked on seem to fail where water pooled under the slab.

You might consider one of the thin electric mats under the new tile set, at least in the bathrooms and kitchen area. That gives you a plan B if the copper tube fails. Also a dual source.

Some of theses kits are DIY friendly also.

jumper

I'd abandon pipes in concrete if they leak too much. To test I'd use air pressure and vacuum.

hot_rod

Is it a glycol system? If it is plain water you would want to use a fill tank instead of a boiler fill valve. So you can detect a leak before you dump hot water $$ into the ground, should a leak develop. A low water cutoff also to protect from a dry fire.

Any movement in the slab? Look for cracks when you remove the tile. Any movement in the slab can be a problem for hard piped radiant systems.

PC7060

hot_rod said:

Too many variables to predict a lifespan. Even the concrete mis itself can has some effect on the copper. Keeping it dry makes a big difference. The copper and steel pipe system I have worked on seem to fail where water pooled under the slab. You might consider one of the thin electric mats under the new tile set, at least in the bathrooms and kitchen area. That gives you a plan B if the copper tube fails. Also a dual source. Some of theses kits are DIY friendly also.

Agree, Schluter Ditra Heat is good option.