Creating access under UFH, set in screed.

[frank999]

I have UFH in a 65/75mm screed, this sits ontop of 75mm PIR.

Running through the 75mm PIR (in cut channels) are 22mm copper pipes - which I need to gain access to.

I don't want to create a nightmare, am hoping nimble use of an angle grinder will alllow me to slice up the screed into thin slices so i can chip it away ... anyone have any experiences of such remedial works under UFH.

I understand the plastic can be repaired if accidentally cut, using a 'repair coupler' and self amalgamating rubber tape. The pipe is: JG Layflat polybutylene pipe.

... 'a wafer thin mint'

Thanks.

 

[plastic_peanut]

Nope, but get lots of pictures. Sounds interesting,

 

[frank999]

Managed to find a leaflet by the final exit door of my local Wickes ... titled 'Project No. 53 - UFH Repair work'. Its got their name on it.

Here's some pictures of the pipes I wish to gain access too, under the screed, before the butchery commences:

 

[Notch7]

Sounds like a job from hell

 

[Celeronmanuk]

Don't think I'd attempt this and would settle for boxed in pipework. Got pictures of the UFH pipes before screed?

 

[frank999]

Agree wish I'd taken pictures before the screed went down, was all a bit rushed - with a wheel barrow race at the end.

Not doing it means a 5 mt dead leg on both hot and cold water supply to a bathroom (unless I replumb and box in on the surface), it will also mean a 6mt run of CH hot pipes under the screed, with no means of control in the room.

Going to start where the UFH polypipe exits at the edge of the screed, and follow the pipes along with the angle grinder, only problem is if the pipes take a turn before I get to the copper, then I have a problem.

 

[sjmac]

You have all that under the ufh- bloody hell. Did they know ufh was going ontop of that lot?

 

[frank999]

Yes they did, it all appeared in one afternoon after I made a loose suggestion the boiler room might be in an outhouse.

Under the screed would have run the feed to the UFH, CHF & CHR, HW and Secondary Circuit - all full of hot water, that would make for a hot floor, regardless of the UFH.

The HW and CW supply T's are quite near to the edge of the screed fortunately. The CHF and CHR could be left with dead legs under the screed if worse come to the worse.

I am sure there must be a method used to repair UFH where the screed has cracked and the polypipe's split, I can't imagine they hack up and lift the lot.

 

[Madrab]

Oh my, you've given yourself a real headache there. Anytime we would be doing a 1st fix into room that was to take UFH & a screed then the mains runs would always follow tight to the wall and then shuttered then the screed poured. then top the resulting channel with metal plate. As it was all run at the wall edge of the floor then it wasn't as much of an issue if UFH wasn't placed on top of it.

Burying service/distribution pipes under screed is never a great idea TBH, built in access is always good practice but that doesn't help you out I know.

All you can do is cut and hope I guess, if your not prepared to condemn what's under there, discard it and re-pipe the services.

 

[sjmac]

Too late now, but at least run it around the perimeter rather than middle of floor. Not sure id want a hw loop running though there - thats the biggest leaker. Nice to see some quality insulation on that pipework

 

[sjmac]

The biggest shame is the pipework is actually is quite neat and shows some skill. Shame they couldn’t stretch to decent lagging. Same old story decent lagging costs more that the pipe and no one prices for lagging its just an after thought.

 

[dilalio]

Hire a thermal imaging camera (or buy one if you like) and draw out the UFH runs on the floor... Least you won't be firing blind.

 

[dilalio]

The biggest shame is the pipework is actually is quite neat and shows some skill. Shame they couldn’t stretch to decent lagging. Same old story decent lagging costs more that the pipe and no one prices for lagging its just an after thought.

The felt lagging is purely to protect the copper from the lime in the cement.
Nothing wrong with it.

 

[sjmac]

Nothing wrong with it in the right situation - what is there to prevent the cold water from heat gain?

 

[frank999]

I will plumb in the UFH and get it working, and buy a thermal imaging camera, hopefully that will help me see where the pipes are.
I did wonder about the lagging, why did they not use foam lagging - these pipes sit ontop of the un-insulated slab, the heat loss ! I was paying for materials and would happily have paid, but they specifically asked for this type of lagging.

Agree about the location, they could have gone round the edge quite easily, and allow for remedial works if they were needed, they probably realised after the screed had been laid.