I'm in the process of restoring these Minton floor tiles and have been removing the loose ones. The concrete underneath them below the first step of the stairway is crumbling and is largely held together thanks to the mortar on the tiles. There's a slight damp smell here as I've been pulling out a few pieces of bitumin and tiles to about 15cm below the surface on the tiles which I assume is acting as a DPC. The rest of the hallway is in good stead so I'm guessing this is a result of kids jumping off the stairs. Can I simply slap down a membrane and fill this hole with a bit of ready-mix concrete? Any objections given the images?
