I'm sound proofing my garage as
part of a workshop conversion...

The walls and ceiling will be faced
with 18mm plywood. at the perimeter
of the ceiling and walls I will need to
use some kind of sealant.

Where each sheet of plywood is butted up
to the next there will be a 20mm rebate.
At this join I am intending to put some
kind of sealant.

What sealants should I be using, keeping in
mind I'm looking for sound insulation.
What is the difference between Acoustic Mastic
and other sealants. (Apart from Cost!)

Many thanks,
Roy