On 6/29/2014 3:12 PM, Mietek wrote:

Hi All,

we just bought a house! In the kitchen next to the door we had tiles
which were broken and moving, it was really annoying every time you step
on them, so we decided to replace them. As the kitchen is done in
extension of the house we presumed that the floor underneath is
concrete, well... it is, but the concrete finishes about 20cm outside of
the door, what follows is rubber like material and there is a hollow
space underneath (it could be a waterproof/damp proof membrane) I
highlighted this on the picture with the yellow circle nr 1, this
material is moving (bumpy) so when you press it you can make a bump in
it and than it will jump out. We thought this membrane is supported on
wood - so we bought plywood and wanted to screw it in to even out that
bit before putting the tiles on - but the screw wouldn't go in (nr 2 on
the pic), I think that the tiles broke originally because this is not a
solid ground it moves and the movement makes tiles to crack and i'm
worried if I will lay the tiles back on it they will crack again, what
would be the best way to lay a tile on this surface?


Sounds like you have the "mushy stuff" and then solid beneath?

Scrape out the mushy and fill that void with self leveling product
typically used for tile floors. Goes down like a milk shake, seeks its
own level and hardens in an hour or so. Great stuff.