Wet underfloor heating possible leak problem

[surfstar]

Hi all.

ive trawled the net and this forum looking for a possible diagnosis to my problem and now hoping you can help.

i have a wet ufh system install a year ago. I've used a polypipe mounted in 20mm polystyrene panels by wunda floor. Under the panels is a latex screed over a concrete floor. The panels have metal heat spreader plates with a 9mm marine ply over the top. On the top of the ply I have karndean.

the house is big and I've used this system throughout however in the last 8 months I've noticed that in the hallway the karndean has warped over a span of about 2sqm. Underneath this section are the flow and returns for several zones. The system has lost about 1 bar over the last 6 months which I put down to the fact I've had a number of other add on manifolds for other floors and general renovations done. However the warping is there and for marine ply to warp there has to be moisture underneath. The system works fine in all zones and hadn't lost pressure noticeably in months.
My worries have increased since I've used a moisture detector on the skirting boards in the hall and they read 13% which considering elsewhere in the house it is 0% it confirms something isn't right.
what can be done to identify and rectify this? I'm not bothered about ripping up the karndean and ply to fix the fault but concerned if I have to replace a whole zones pipe

thanks

 

[ShaunCorbs]

best bet before hand is to pressure test each zone and find out if you do indeed have a leak

 

[lame plumber]

get the installers back, use a flir to check for leaks and be sure it isnt just moisure fm your sub base drying out.

 

[surfstar]

Thanks. I installed the pipe and plumber terminated on to manifold and pressure tested. I like the idea of the sub base drying out!

 

[Chalked]

Was a vapour barrier installed?

 

[Unregistered]

No vapor barrier installed

 

[Chalked]

Could be drawing moisture from underneath if no vapour barrier was installed.

 

[GSAL]

Wunda and polypipe do repair couplers, there quite bulky so may need to butcher the polystyrene to allow it to fit. Much easier that replacing complete pipe..

Be sure you have a leak before breaking up floors...

If the warping is in a transition area where all the circuits leave the manifold, it could be caused by excessive heat? If having wood with UFH its a good idea to fit a high limit stat in the floor in these zones.

You would think ifs it caused by lack of vapour barrier then you would have this problem all over?

I hope this is helpful

 

[GSAL]

* if it's.....

 

[jonnyswamp]

Could be overheating in that area, wunda floor recommend a over temp stat to be fitted where natural timber will be used
Iirc 27 deg, the stat probe/sensor should be just under the timber flooring

 

[ben5192]

wouldnt show on moisture sensor if was too much heat?

 

[gassafe]

Is that laminate flooring, Iv seen it all rise up if there's not the correct expansion gap around the area, maybe that is what's happening?

 

[gassafe]

If there's no joints in the underfloor pipework it's unlikely to be leaking

 

[jonnyswamp]

wouldnt show on moisture sensor if was too much heat?

I didn't mean a leak, I meant excess heat causing warping of timber

 

[Worcester]

I didn't mean a leak, I meant excess heat causing warping of timber

If you have a lot of ufh pipes concentrated in one area, it is good practice to apply an insulation layer over the top of the pipes to stop overheating, even more so when it's not embedded in screed.

You have 3 possible causes of warping
1) leak
2) Overheating
a) Expansion of floor without sufficient gap bending
b) Warping of the floor


I do get very confused though why people spend a small fortune on the floor covering (karndean) and skip on the underfloor heating system.