Ufh And Duck Tape

[spamcal]

Hi all...

When installing UFH I've always used the sticky mats but the main frustration I have is that the mats are not that sticky. I've tried using SPF adhesive to stick the mat down but found this time consuming so I've always used Duck Tape to tape down the cut edges and loose cable when going round obstacles (toilets pedestals etc.) Even then I still find the cable can poke through the SLC. In these cases I use two off cuts of tile and using the edge balance them together to weigh down mat in the SLC then easily remove the off cut tile once the SLC is dry.

My problem is I have recently been contacted by a customer saying his mat has over heated and blown. The warranty has been declared void because the manufacture claimed the over heating was due to the Duck tape. So if this is the case, firstly I have to change the way I install UFH but secondly I wondered if anyone else had come across this problem?

 

[Old Mod]

If the UFH cable is not fully covered by adhesive or SLC and air pockets are formed, this is what leads to cables overheating and burning out.
Covering cables with duck tape to hold them down can create a air pocket around the cable if it's not stuck tight to the cable.

 

[spamcal]

Thanks for your reply. So it suggests duck tape will cause problems if not fully stuck down, however interestingly, it does say on the manufacturers web site to use duck tape to stick down loose cable but nothing about air pockets and the dangers of not sicking down properly.

 

[Diggy]

When using Devimat I always used to prime the day before with BAL Prime APD ( not SBR) or similar . This pretty much made sure the mat stuck to the floor , of course there is always a little tape needed on the turns or a squirt of carpet spray glue , but not much.

Diggy

 

[Old Mod]

If you're gonna use duct tape u'd need to tear it into small thin strips about 20mm wide so u don't easily leave air pockets.
I'm sure u'll find somewhere where it says completely cover cable with adhesive or SLC.
Or must be completely embedded in adhesive

 

[Time's Ran Out]

I always go the time consuming route and fix with fast setting flexible adhesive.

 

[Old Mod]

Personally never use mats, more trouble than they're worth.
Always loose cable if I can.
Think this is a perfect advert for that.

 

[Tile seller]

Interesting, I met an electrician within the last week who specialises slightly in electric UFH failures. He said that most of his call outs are because the last part of the heating cable, where it joins the mains,are not buried in adddy/Slc. Apparently the flex(rather than the core of the mains) requires a heat sink to survive. Apparently, the flex will often do 12 months before over heating to failure.

 

[hmtiling]

I use a glue gun to stick the bits that tend to curl.

 

[White Room]

Glue gun for me also..

 

[spamcal]

Thanks for the replies. Sounds like it SPF or glue gun from now on. But interesting the comment from 'tile seller' and his electrician friend saying most of his call outs are from exposed cable. How big a problem is this?

 

[White Room]

Always bring the slc over the cables, 2-3mm...

 

[John Benton]

Thanks for the replies. Sounds like it SPF or glue gun from now on. But interesting the comment from 'tile seller' and his electrician friend saying most of his call outs are from exposed cable. How big a problem is this?

It's a potential problem for anyone who doesn't completely encase the cable with slc, so there will be plenty out there.

 

[hmtiling]

Dot and dabbers!

 

[jobdone]

Just removed a failed floor part of the mat underror the bath completely exposed and the rest of the floor held down by the double sided tape on the mat. Mat worked fine how does that happen? Loose cable and glue gun for me.