Soundproofing.

[jonnyb]

When I was putting seat belts in my 1.5 I was pleased to find good carpet and underlay on the floor front and rear. However, under the rear seat and back into the boot was devoid of any soundproofing. This area happily drums away at various frequencies and the exhaust runs close to the floor under the nearside passenger's butt. As it happens my brother has a Minor Traveller which he was soundproofing and offered me the remains of the kit he used, Silent Coat 2mm thick damping pads 20 sheets! Easy to apply, cut to shape etc. Half done so far and rear seat now back in place. Enough left to do the boot too.

Before:

After:

[canuck]

Well done Johnathan,  and hats off to your benevolent brother 

I did double duty. I added a bitumen self adhesive sound attenuation material, (B  Quiet)  to the flat floor panels. I also added a patch to the inner doors.  I read up on this and to reduce the 'drumming' one doesn't require the full surface to be covered
I did add to the under rear seat area as you have done. The silencer does transfer heat and the bitumen doesn't play well, wrinkles as shown below



however once 'wrinkled' has stayed fine over the many years. 
Directly under the carpet I them added a 9mm thick felt to absorb some sound, and perhaps some heat?  I left an offcut of this under carpet felt floating about under the rear seat.   

Anyway in doing this has certainly helped, and the doors slam with a 'thud' versus a 'clang' now. 

B