Just how bad is my artic window sill?

[markglos]

A small attic window sill was just smooth plaster, at least 40yo maybe older. Top layer came off when I gave it a hoover one day and the next layer came off easily in big chunks, I took a section up to see what was underneath (see photo)

I'm an amateur here but I'm guessing that I'm seeing the rubble interior of the wall? Or it is worse than that. The larger stones are loose. Would be nice to remove plaster and return to sandstone if possible.

Many thanks

 

[a twig]

Yep, looks as expected, the stone around the window looks a bit beaten up and has had some filler in the corners but nothing that couldn’t be stripped or dug out, and then damage repaired with an appropriate NHL based stone repair mortar.

In terms of putting in a new sill - plenty of options, slate, natural stone tile, stone or timber depending on decor and context.

Damp the top of the rubble wall down with a garden sprayer and then fill in / level off with lime mortar to give you a flat surface for whatever you want to put on top. You might want to use small bits of stone to help fill in the larger holes.

I’d personally use NHL 2 or NHL3.5 for that job in a 1 part NHL, 1 part sharp sand, 2 parts builders sand mix

 

[markglos]

Thanks that's a relief!
,

 

[markglos]

Would be nice to have stonework. I'll try for that I think.