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Old 22nd June 2020
Gear Head

Rubber underlayment on top of thick concrete floor slab?

Hi all - first post.

I'm endeavoring to build a very small recording / mixing combo room (Trying to follow Rod's book to the extent that I can) and have a specific flooring question.

In my situation, I had a very thick concrete pad poured to raise floor level. I won't get into specifics on why or what else I could have done - it's done & was my only option. So, I have a very thick, smooth concrete pad for a floor (not polished /shiny).

I was advised by a sound engineer who came out to consult me on some aspects of the room (a year ago, when I knew even less than I do now, and hadn't yet started to read Rod's book or to review this forum), and he told me that "It's great from an isolation standpoint that you have this solid massive concrete floor - if you want to do a hardwood floor over it (I do), then you should put a rubber underlayment underneath - the stuff they make from recycled tires", and mentioned that he thought I would improve the acoustics of the room from doing this. From my memory of my conversation, it seems that he thought this would make the room a bit 'softer' in terms of reflectivity - which is probably a good/necessary thing in my context.

Now, I know that the underlayment will help with impact noise, but I'm wondering about thickness to use. I saw Andre comment on a somewhat related forum that a thin layer of underlayment may make things worse in some situations. So, I'm wondering if someone can advise on this?

My primary concern is getting the best acoustics I can in what will already be an acoustically-problematic small room (12.5' X 6.5' with a vaulted ceiling that goes from 8' height to 10.5' height. Isolation shouldn't really be the driving force on this one.

This room will be 95% used for me recording my acoustic guitar parts, & the odd electric guitar parts, maybe vocals. No drums, no full bands, etc, so the lowest frequencies aren't my main concern. Practice with my songwriting partner, etc.

Product that I'm seeing is:[/URL]

Spec sheets are attached for different thicknesses.

for 6mm (1/4") thick material, $200 will cover my floor, price jumps to $300 to cover at 12mm (1/2").

Any ideas - I see some posts about underlayments over wooden floor joists, multi-floor structures, but haven't seen one for the concrete slab situations I'm in.

Thanks if you have any idea on how I might proceed.