Thread: Polybutylene Tubing in Hot Water Radiant Flooring

Hi folks,

I know the concerns with the use of PB for hot/cold water supply piping, but do not know if the same is true with heating systems. I have searched a bit and have found some companies still manufacture PB for both uses, but cannot tell if it sold/used in the U.S. I also cannot find any mention of widespread failures in heating.

I recall reading several years ago (probably a post here) that PB was not approved for heating; however, I went through an installation manual (from the Plastic Pipe and Fittings Association) that I have and PB is in their list for heating in "other uses". I realize this does not necessarily mean that it is listed and approved for heating.

I have seen a few homes with PB as a part of the hot water radiant heating system and have not seen any problems with them (recognizing I can't really find a failure in a slab). I still notify my client that there are concerns with the material when used in potable water distribution, but was wondering if others have any thoughts or specific knowledge in heating.

Thanks.

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Gunnar

In aid of your research.

Home Improvement Information - The facts about Polybutylene Pipe Issues - Shell Busey's HouseSmart
Plastic supply water pipe law suits : Poly-B, Kitec, PEX fittings...

Originally Posted by Raymond Wand

In aid of your research.

Home Improvement Information - The facts about Polybutylene Pipe Issues - Shell Busey's HouseSmart
Plastic supply water pipe law suits : Poly-B, Kitec, PEX fittings...

I disagree with Mr. Busey's cavelier assessment that if you have poly-b only for domestic use, then you have little to worry about. I don't see a lot of poly and yet I've seen it fail or failing several times.

Not sure if this helps but I recently purchased a home in the northeast a couple of years ago - the home was built in 1987 and had PB. The entire forced hot water heating system was plumbed with PB as were all the hot and cold water lines.

We recently had a failure where 1 heating zone had sprung a leak under the slab. It heated up my whole utility room - unexpected radiant heat in concrete.

We ended up replacing with PEX by going above ground. As a side note, we have 6 heating zones - 2 of them were underground. Since we were replacing the 1 underground line, it only made sense to me to replace BOTH underground lines for only a little bit more in cost - just in case the 2nd underground line wasn't far behind in terms of failure.

That said, I knew when we purchased the home that it had PB and I deducted from the purchase price knowing the replacement cost, all in, was around $25K. I had read all about the class action law suits (which are expired and can no longer be claimed against) as well as the risk. Also, if I am remembering correctly, it was chlorine or some such in city water where a bulk of the PB leaks seemed to occur. We are on well water and the water tests came back clean.

This piping has lasted for close to 30 years - the only failure of the actual piping in my home was underground. I'm not endorsing this piping and I want to get rid of it when the budget allows - but that said, my experience is that the underground contact is a bigger problem with all the minerals in the dirt I suppose.

My heating system is original and it has been pumping 180 degree water through those lines for a long time. If I had a choice I wouldn't install PB - no how no way - but if it's already there and shows no signs of failure, I'm not sure I'd be all that concerned in practice. It absolutely MUST be disclosed though to any home buyer because the product has been proven to fail under certain conditions - especially those with city water.

hth!

Here is a thread from another forum:

In-Floor Hydronic Radiant Heating Sys. w/PB Pipe - The Inspector's Journal Forums

It appears that the problem is not just with the polybutylene failing but the older polybutylene does not have an oxygen barrier which leads to faster deterioration of the boiler itself.

Thanks guys. All very helpful.

Originally Posted by Gunnar Alquist

Thanks guys. All very helpful.

Here in FL there currently is not one single insurance company that will insure a home with PB. My guess is that will spread - just an FYI.

Originally Posted by Bruce Lunsford

Here in FL there currently is not one single insurance company that will insure a home with PB. My guess is that will spread - just an FYI.

Fair enough Bruce - good info.

Fwiw, I did check with my insurance company before I purchased the home to confirm that they indeed covered losses resulting from PB - they said it was covered. My insurance company is Liberty Mutual.