HappyHunter wrote:
Dave Liquorice wrote:

Packing to make plumb? Vertical so that the new wall is plumb yes but
unless the old wall is really off just have packing so that the studd
isn't stressed over lumps/bumps on the old wall. Remember you can
knock small high points off the wall to get a closer fit.


It's a very old building. 3 walls are mainly sandstone. 1 wall rebuilt
in brick with cavity some years ago I guess (so 2 lines of brick with
cavity in between).

One of the sandstone walls has brick repairs in it (quite large
sections, but high up). Another sandstone wall has various "stones" in
it as well, not sandstone blocks or brick, look like big lumps of stone
(which I'd image would be horrendous to drill into, but that's not the
wall the frame is going on anyway).

I think I'd aim to fix the frame to the "best looking" largest blocks I
can see. I've repointed a lot internally so lots of the old pointing is
gone, but I'd guess, scrape beneath that initial layer and there will be
a right mish mash underneath. You know, I found sea shells in the
pointing ! Does sort of look like they maybe visited the beach to get
something to mix with the cement (or more likely lime).

Cheers
Ailsa
If you can get a few fixings into blocks you could consider leaving a
small gap and injecting some expanding builders foam. This stuff not
only fills any gaps but sticks to most surfaces and will add strength to
your first stud. Possibly best to use screws in the noggins and adjacent
studs rather than dislodging anything by hammering.

Bob