On 25 Jul, 08:52, JP Coetzee wrote:
On Jul 24, 8:49 pm, Andy Dingley wrote:

I'd suggest attaching a "sub-batten" alongside the wall battens and
stapling the foil down to those.

How about if I staple the foil "half-way down" the thickness of the
batten, i.e.:

If you can do it without putting excess tension of the foil _and_
without leaving the foil loose enough that it can flap around and rest
on one of the inner surfaces .