Shortly after the Christmas pud has settled down I'll be starting work on my
new garage. The flank wall is 'half brick' with pillars ie approx 100mm
thick. Due to its length (7 metre) it needs an expansion joint. I understand
that the conventional wisdom is to tie the two bit of wall together with
normal cavity wall ties 'along the length' of the wall, with one side
wrapped in a bit of dpc to let it slide.

But what is used as the 'spacer' between the two bit of 'end to end' wall?
(ok I know it needs sealing with a flexible mastic but what is the filling
in the sandwich ?)

Andrew Mawson