How fit interior window board/cill

[bboy101]

Hi, can anyone give some advice on this;

I am re-doing my bathroom and when I took the tiles off the interior window board/cill, I found that the plaster/mortar was broken and came off with the tiles, not the problem. The problem is the board that was covering the cavity had snapped and came off with tiles, leaving me with plaster on top of inner wall but then the open cavity to the window on the outer wall. Therefore how do I cover this now to allow me to tile over it? Could I just use a board fixed to the top of inner wall, but not sure how solid that would be. Many thanks for any ideas.

 

[noseall]

Look here.

 

[pinenot]

Put in a length of cavity closer/insulation, with a single dpc side flap to the inside wall then proceed with plasterboard build up to the level you require for tiling, fixing with gun applied glue, then tile - seemples - ...pinenot