How to fill hole in floor

spud

Any advice welcome. Following a leak that penetrated under the floor tiles, it seems to have weakened a probably already weak floor. FYI the floor has underwater heating, though haven’t encountered any pipes thankfully. I have removed most of the loose material.  Anyhow, what would you recommend I use to fill it? Don’t want to use the wrong thing. Many thanks,
Spud

Alderbank

What is underwater heating?

flashg67

Replace like for like ideally if you can identify what it is - will cause less issues with any stability/incompatibility in the future

spud

Typo for underfloor lol! 

If I can’t determine exactly ( may not be an option) what would you use? 

MikeJXE

No one will be able to advise without seeing the floor

Photo please 

spud

Fair point. Hope you can view this. 

MikeJXE

If that is a concrete floor after tiles have been removed.

Clean it up, grind off the high spots and remove all dust 

Level with good quality self levelling compound 

35har1old

MikeJXE said:

If that is a concrete floor after tiles have been removed.

Clean it up, grind off the high spots and remove all dust 

Level with good quality self levelling compound 

Looks more like flagstones 
Do you feel any heat from the under floor heating?

FreeBear

MikeJXE said: Level with good quality self levelling compound 

Paint the affected area with a suitable primer (SBR ?) first. This will help the SLC to bond to the existing screed.

spud

Thanks all. Not flagstones. The edges of the tiles may give that impression. Yes, the underfloor heating works a treat. I’ll go with Primer and slc. 

Kiran

I'm sure you already know this, but make sure you get the correct self leveller for underfloor heating to avoid cracking