PeteH
Sorry I have just seen your post, I applied it on a warm day and did not noticed any odd smells nothing to make me question the material, anyway in our car after 30/40 hears you should have strange smells, my Spitfire has a lovely smell completely different to the GT6,which has quite an empty smell.
I am very happy with it on the inside of the gear box tunnel.
Go for it, a lot better value than the other products on the market.
Once when watching one of those US car programs they applied sound proofing to a pick up truck and it was just patches to stop the drumming.
With regards to houses the noise would transfer through the joists, in a program about cross rail being built under a concert hall they put the rails on absorbing material to stop vibration, and vibration is just a lower wave form to sound.
Graham