As standard, Defenders, do not come with a sound proofing on their roof or side panels. This leads to two things, condensation and noise ingress. The simple way of solving both of these problems and making the Defender a nice place is to add some closed cell foam insulation.
Here we can see the standard, bare state, that the panels are left in from the factory.
The side panels had chequerplate over them when the vehicle arrived, however this can lead to "drumming" of the panels, which is amplified by having a space inbetween the side panel and chequerplate. The soundproofing will prevent this from happening.
We start at the front and work our way back.
It will be much quieter and warmer inside the vehicle with the insulation installed.