How to patch this hole where the wall meets the subfloor?

[PipeDownSoldier]

I've ripped off some wall tiles as part of my bathroom renovation, and found these large holes (2-3" high in places) behind the tiles, where the wall meets the floor. The subfloor doesn't appear to run under the wall, so I'm not sure how to fill the gap if the filling material cannot be supported.

The wall will eventually be plastered so maybe it's a moot point. I wasn't planning to have a skirting board, but even if I did have skirting, the idea of having a gaping hole there behind it still doesn't sit well with me.

Any ideas? Maybe use bonding plaster and build it up slowly in layers?

 

[Lower]

Trim the plasterboard up the wall 6 inches and put horizontal strips in that go down to the floor.

 

[PipeDownSoldier]

Trim the plasterboard up the wall 6 inches and put horizontal strips in that go down to the floor.

Unfortunately the existing plaster is adhered directly to the masonry (there is no plasterboard).

 

[Lower]

If there is masonry behind the holes, just use bonding. I thought you were saying there is nothing behind the holes.

 

[PipeDownSoldier]

If there is masonry behind the holes, just use bonding. I thought you were saying there is nothing behind the holes.

Sorry I haven’t explained myself very well.

Where you see plaster is where it is adhered to masonry.

However; where you see the hole, the masonry is no longer there, so there is no backing material - just empty space.

This is further complicated by the fact there is no subfloor inside the hole (beyond the flush surface of the wall) ; so if I applied a filler of some kind, there is neither a floor surface or backing surface for it to adhere to.