What a day it’s been today, had 5 bags of flexible self levelling compound which is thought was going to be enough, turned out I was wrong, had to go pick up another 4 bags mid job, and somehow I managed to buy the only one known to man which is not recommended for underfloor heating!! I didn’t even realise there were ones which weren’t suitable, learn something new every day. Anyhow, before I’d realised since I’d already started the job, it was mixed, laid and going off, was only when I checked to see how long til it set I saw the not recommended for use with underfloor heating!!

 

luckily the majority of the underfloor heating is covered with the suitable stuff, with maybe 1-2m2 covered with this one. Have had a look online and the only thing I can find is that it may craze/crack under use? If that’s the case it doesn’t bother me as long as the heating mat is safe, since I’m using LVT over the top as a floating floor.

 

anyone else made the same mistake? Though since 90% of the products are Ok with it, it’s stupidly hard to do!! 😂 

 

This is where the mat is

 

the grey self leveller is the flexible, the browny coloured one the non flexible 

 

 

You may be lucky. It's possible that the manufacturer hasn't tested it for ufh and is being cautious.

It suggests adding latex liquid would have made it suitable, but again too late now.

 

what’s worst case scenario? Can’t imagine it’ll chemically damage the UFH as it’s ingredients are the same as the flexible stuff, obviously missing a few components.

 

the bag doesn’t even state unsuitable for UFH on the limitations section, it’s in the application section

Edited July 20, 20242 yr by MikeGrahamT21

Any suggestion why? Do they mean warm water or heated wire anyway?

No it doesn’t specify, just says unsuitable for underfloor heating or floors which have minimal movement/vibration. I’ll hazard a guess it’s to do with flexibility, this is a C16 strength F4, whereas the flexible stuff was C24 F8. Just wish I’d had known there were different types as I could have bought some latex at the same time to go in it, or a different product which they had but said it was for interior and exterior use, was in a rush and just kept it simple, and now wish I hadn’t 😂 

 

I’m not too bothered about cracking and it’s got no where to go, the LVT which I’ve got going over it has a thin layer of neoprene padding on the back which won’t be bonded in any way to the subfloor. Guess I’ll just have to leave it a few days to dry out, turn the UFH on and see what happens, and if it seems OK run with it, at least the LVT can be taken up at a later date if I need to redo it all as worst case scenario 

Easily done can't see there being an issue for a floating floor. If you tired... Just stick a layer of flexible over the top.

Definitely not tiling, that’s one of my most hated jobs of all time! Not a tile to be found in this place now 😂 

I’ve gotten past the ‘DIYers blind panic’ stage, what’s done is done, though I’ll remain annoyed at myself for a few days I’m sure 😂 

 

was going to do that small area of plastering tomorrow, but after the stress of today I think I’ll have a day off!

Don't do what I did and and add insufficient water (distracted, rushing and wasn't thinking) then dump it, and half way through spreading it realise.... Then over work it... Then try and spray on water..... Then rip it all up.

 

Bastard thing.

1 minute ago, Andehh said:

Don't do what I did and and add insufficient water (distracted, rushing and wasn't thinking) then dump it, and half way through spreading it realise.... Then over work it... Then try and spray on water..... Then rip it all up.

 

Bastard thing.

made sure I measured the water as per packet instructions, and it self levelled, seemed a good consistency.

 

we do set these things on don’t we? 😂 whilst googling about this, seen so many stories of professionals using wrong products too, and that’s only from the customers who noticed, I bet it happens more often than you’d like to think