Quite welcome and good luck with the project
. If you're looking at the Soundown maybe I should add some more detail.
Soundown for marine
engine spaces (they make all sorts of sound products) is a three later; foam sound absorbing on the outsides with a high density barrier layer in the middle. It comes in different weights and thicknesses, obviously the thicker/heavier gives better results. I got the 2" which I think is the max since I have an old, noisy Westerbeke
. Still finishing the installation
but I do have to caution that this stuff is HEAVY and a bit awkward to handle in large sheets. However, I'm expecting great results (cross my fingers) since in a test a few years ago Practical Sailor gave Soundown the best rating. Might go for the 1" or 1.5" for easier installation
and a bit cheaper.
I know a guy that did his engine room in a product that comes in 12" square tiles. Probably much easier to install but have not heard from him on how well it worked. I think he just launched so maybe time to drop him a line.