On Mon, 1 Feb 2010 11:30:57 -0000, Dave Baker wrote:

Position your studding against the wall where you want it to be and mark
the studding with a pencil where there's a mortar joint in the wall or
else you'll end up drilling into stone which would be very hard work.

I'd go for the block/brick/stone rather than a joint. Even modern
cement mortar is very soft and really hasn't got much holding
capabilty. This building sounds like and old place, the mortar may
well be lime based which is even softer. An SDS drill makes short
work of most building materials even with a 10mm bit that frame
fixings might require.

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.

--
Cheers
Dave.