Damaged concrete floor in bathroom

[magicman-alex]

Hi All,

I've just ripped out my bathroom as the previous bathroom installation and tiling job was pretty bad and I figured it was a good chance to try my hand at tiling.

It's a 1st floor maisonette and I've suffered with leaks into the flat below due to a poor bathroom installation. I've removed all the tiles.

The bathroom is an uneven concrete floor, so I'm guessing self-levelling compound will be in order at some point. However, when I removed the bath, I found there's a hole in the concrete that appears to go into a void above the ceiling of the bathroom below. I'm not sure how best to fix this hole before applying the self-levelling compound. A mate suggested fixing an old tile over it and then pouring the self-levelling compound, but I'm worried that a tile might be too thick and will just complicate things.

The hole is probably about 15cm x 20cm and the concrete itself is about 25mm thick.

I guess I could probably screw or glue on a very thin sheet of steel plate or something like that, but just wondered if anyone had any better suggestions.

Thanks in advance.

Alex

 

[m3fitter]

if its not taking any weight, try expandable foam, and cut it back flush afterwards when its dry before latexing

 

[Andy Allen]

Just mix up some concrete or sand and cement and fill in the hole.....diy sheds sell small bags you just add water to..

 

[m3fitter]

Just mix up some concrete or sand and cement and fill in the hole.....diy sheds sell small bags you just add water to..

thought it was bottomless ? ie: through to downstairs ?? that's a lot of sand and cement Andy ! lol :yikes::lol:

 

[Andy Allen]

thought it was bottomless ? ie: through to downstairs ?? that's a lot of sand and cement Andy ! lol :yikes::lol:

Lol didn't see that bit......thought my answer was a bit obvious. ...:lol:

 

[magicman-alex]

Thanks very much for everyone's input. I'll have a go with the expanding foam and see if that helps (will self levelling concrete be OK on top of foam?)

The 'void' underneath appears to be about the standard size of a space under a floorboard. I know the neighbour's rear hallway is directly underneath so I'm guessing it's just a plaster board ceiling below the hole.

Thanks again, Chaps.