[cornerstone]

Originally Posted by TA_C10

So, the butyl stuff dampens the metal, vibration. The butyl won't burn either so it can take the heat but doesn't really stop it from passing through. That's where the shiny stuff comes in. It's foil backing can do a bit of heat isolation/reflection.

Closed cell foam does 3 things we care about. It absorbs sound. It insulates. It doesn't absorb moisture. Closed cell foam has been used in acoustic rooms for years like radio booths and recording studios. Many other uses too. But you get more sound and heat/cold insulation from the closed cell foam than you do the foil backed butyl.

This is why car manufacturers use only small patches of the butyl stuff(or similar) because they figured out it's main advantage is vibration dampening. You only need it strategically placed to do it's job correctly. Then they focus on insulation under the carpet. The insulation they choose has the same 3 property's that closed cell foam has. Jute padding usually. But some use CC foam too.

Price is our big factor too. While you do get benefit doing the whole floor (not just strategic small spots) with the butyl. Its nothing compared to what closed cell foam can do. But put the two together, and that's Bentley comfort baby

Another way to put it:
Butyl stops the metal vibrations and oil canning.
CC foam absorbs the muffler drone, makes your stereo sound better that it really is, and keeps you comfortable in the winter and the summer doing it.

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Thanks man. I think I’ll get some of the closed cell stuff on order also, because I’m all about Bently comfort.