Underfloor heating/issue with builder

[Andy Allen]

Correct me if I'm wrong but with the loose wire system, don't some manufacturers supply the installer with duct tape to run along the entire length of the cable? Surely this will leave voids and possibly overheat? How is this different?

Mike

It's not duct tape.....it's like the scrim tape plasterer use......at least the last one I did was..

 

[thickbed]

These are the other pics

 

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These pics were taken by the guys who did the repair, someone still needs to go and replace the 2 tiles they ripped up.

 

[thickbed]

It's not duct tape.....it's like the scrim tape plasterer use......at least the last one I did was..

The last loose wire system I laid (admittedly it was a few years ago now) they supplied a thinner strip of duct tape to be run along the length of the wire to secure it down

 

[Dumbo]

thanks Paul C I would rather not say at this time

I don't why . They given you what they think is a legitimate reason for failure so why not say . As I said I had exact same problem with thermonet .

 

[One Day]

I have always tried to keep the tape as tight as possible to the cable. Avoid any air pockets around the tails (and joints on bespoke cables).

Picture of a recent job shows how I've just stuck the tip of the tail down to stop it curling up, but the main body is set down in cut out thermal board.
(you'll probably need to click and zoom!)

 

[Dan]

Very very neat layout there @impish I like it

 

[One Day]

Very very neat layout there @impish I like it

It's my OCD!

 

[Dan]

That's why it attracted my attention lol soothing for the OCD in me ha

 

[One Day]

I love installing it. Sad but true!

 

[thickbed]

So the repair man has been recommended by the manufacturers. Would love to know how many failures he attends and reports a manufacturing failure, probably not very many as he may not have much more work coming his way
Just a thought

 

[Dumbo]

Still want to know what mat

 

[thickbed]

Lovely neat work impish question:
Where you have used duct tape to secure the cable in place, can you be 100% sure there are no voids between the cable and the tape? I'm just comparing my masking tape situation to your duct tape and TBH I cant see a difference

 

[thickbed]

I don't why . They given you what they think is a legitimate reason for failure so why not say . As I said I had exact same problem with thermonet .

What was the outcome ?

 

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thermonet are meant to be the muts nuts of UFH systms aren't they

 

[One Day]

Lovely neat work impish question:
Where you have used duct tape to secure the cable in place, can you be 100% sure there are no voids between the cable and the tape? I'm just comparing my masking tape situation to your duct tape and TBH I cant see a difference

Nope. Can't be 100%. But I believe that the cables aren't the weak spots.
Tails and joints are. It's stressed by all manufacturers that those must be embedded.
I always flood my cables (and occasional mats) with slc which is a safer bet than adhesive straight on. Far fewer air pockets - tape or no tape I guess.

 

[thickbed]

Nope. Can't be 100%. But I believe that the cables aren't the weak spots.
Tails and joints are. It's stressed by all manufacturers that those must be embedded.
I always flood my cables (and occasional mats) with slc which is a safer bet than adhesive straight on. Far fewer air pockets - tape or no tape I guess.

Agreed I also always use levelling compound which is why I cant seem to get my head around why this has happened

 

[thickbed]

Thank you for all your input I will keep you updated

Mike

 

[Dumbo]

What was the outcome ?

Main contractor who supplied heat mat paid for repair but asked me to go and replace Tile which I did . But until you have one of these situations you don't realise how critical some aspects of it are . Personally where possible I am going the use the system where the wires push into membrane to limit the amount of tape used like the Variopro system

 

[Sean Kelly]

I am thinking that these are the sequence of event:

The UFH has failed.

The customer has contacted the builder.
The builder has contacted the UFH company.
The UFH company has given the builder the number of a person than can seek and repair the damage. If the damage is caused by a faulty cable then the UFH company will bear the cost of the repair.
The repair man has located the problem, removed the tile/tiles and made the repair. The repair man is independent and impartial.

He has identified that the problem is due to the end of the cable getting too hot and the glue has melted on the end cover. The end of the cable must be encased in tile adhesive or SLC. The adhesive and SLC draws away the heat from the cable. If there is a pocket of air around the termination block then the heat generated by the cable is not drawn away quick enough.

The repair man has tested the cable and found that the problem is caused by the installer - sorry.

The repair man gives the bill to the builder.

It seems to me that the builder thought that the problem must be down to a faulty cable but got a shock when he was given the bill (he got the bill because he contacted the UFH company).

In my opinion the builder should have contacted you as you had installed the cable. You would then have rung the UFH company and you would have been given a bill of £360.

The chances are that you would not have found the fault by yourself and you would have had to call in the experts anyway.

The builder has learned a lesson............a lesson that has cost him £360 !!!


You either split the difference with the builder or let this run and run.

 

[thickbed]

Hi Sean Kelly

Pretty much spot on although if I was notified in the first instance, I would of gone in with my sparky( have done 2 of these in the past and have been compensated as it was a manufacturing fault ) and if it definitely was below tiles. started with taking up the tile with the cold join beneath it and if it wasn't that joint then move on to the end tail (termination join) At this point if we couldn't get it working, I would have called in the proffessionals and would have paid them to sort it. There are only 2 joints in any one mat, 99% of the time if it fails, it will fail there.

 

[Martyn Leeds]

How much work does this builder bloke give you?

 

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Not a lot

 

[Dan]

He should have called you really. It could have saved him some cash.

 

[thickbed]

Also does anyone know what this means- it was one of the notes on the bottom of the report

Resistance reading less than 999Mohms of heating element to braid (or earth) indicates heating element
insulation damage. Heating cable in working order although low resistance reading may deteriorate and cause future
failure. Fault location not attempted with element to braid (or earth) resistance above 10Mohms due to risk of damage
to heating cable. IEE Wiring Regulations require minimum insulation value of 1Mohm for general supply wiring