Floor insulation HELP?

Hello all. I need help. I'm building a vocal booth. The floor is made of 2x4's on top of tile. MDF will be placed on top with laminate on top of that. My question is should I put insulation iside the 2x4 framework. Any help wuold be great. Thanks all

Hai FrankAlex, IF you've got a framework already, I'd say YES fill it with wool to absorb sound and lessen vibration in your floorboard. Else that floor really's gonna be one big resonating "drumskin". (it already is, but with wool you lessen the effect)

Thanks ro. how about r13 or r15 rools? what kind of wool pruduct can I use? Thanks

this thread touches on some insulation concepts.. http://www.johnlsayers.com/phpBB2/viewt ... n+compress "Also other studies show that. I admit there is some slight contradictary infomation available, but in general one can state that no study advices to increase density for low frequency insulation (which is the defining factor) and the previous paragraph confirms the negative effect of higher densities on low frequent isolation." actually, reading further, there are some good words of insulating concepts discussed further down... I did limiting searches relating other terms that may help, but I found myself getting off in tangient land and need to get back to the day job.

i got some good advise from knightfly to use 4-6 psf rockwool just slightly compressed.

Thanks to all for the help Sorry for the ignorant questions but is rookwool equivalent to regular roll insulation? I ask because the rools you would buy at the local building supply are more accessible. thanks

Frankalex1967 wrote:

Thanks to all for the help Sorry for the ignorant questions but is rookwool equivalent to regular roll insulation? I ask because the rools you would buy at the local building supply are more accessible. thanks

Your direct question is covered in rods book. I just skimmed through it, but could not find the mention where (paraphrasing) the difference between rockwool and fiberglass insulation of comparable thickness and rating is nominal. I wish I could find the quote to do it justice, but it was in the wall construction section I believe. hope that helps.

The benefits of rockwool (a.k.a. "mineral wool") insulation vs. standard fiberglass batts has been discussed here a few times over the years. Some very credible gents (Rod being one of them) believe that the use of mineral wool products inside of walls is overkill as it is more expensive than standard fiberglass batts and offers little, if any, tangible benefit in terms of additional isolation. As long as there's enough fill or something like nylon straps to keep the insulation lightly compressed against the back side of the drywall, it should work fine. Mineral wool (namely Thermafiber Sound Attenuation Fire Blankets (SAFB) - Nominal Density (2.5 pcf) and Roxul Acoustical Fire Batt (AFB) - ≥2" (2.5 pcf)) is a favorite for do-it-yourself acoustic treatments and is far superior to fiberglass batts in this context -- so much so that I'm pretty sure it's a "don't even bother with fiberglass" when it comes to acoustic treatments. Also, mineral wool has far superior fire resistance properties, which is especially good when you consider that many do-it-yourself acoustic treatments are made to hang on the wall like picture frames -- use of a fire resistant fabric completes the job of a nice acoustic treatment that doesn't attract fire like a magnet. That being said, I did order 19 bags of mineral wool insulation for use between the walls and above the ceiling in the space I am building. I decided I wanted to err on the side of overkill, but what really clinched the deal for me was seeing videos of two test structures, one insulated with standard fiberglass batts and the other with mineral wool, and seeing how they reacted to fire. Hands down, the mineral wool kicked ass. I also recently reviewed video of the infamous night club fire in West Warwick, Rhode Island, which reminded me of the destructive and deadly power of structure fires, especially when safety regulations are not followed and when venue owners don't take seriously their responsibility to only use fire resistant acoustic treatment products. The owners of the station used non-fire resistant packing foam as a cheap alternative to proper materials, and that was one of several key factors that cost one hundred innocent lives on that fateful night of February 20, 2003. Unfortunately, mineral wool insulation is often more difficult to obtain. Home center stores tend not to stock it, and even specialty sellers don't carry it in a good variety of sizes. I had to settle for 24" wide batts, even though my studs and ceiling joists are 16" o.c.! :x I'll be doing a lot of cutting... :roll: ...I was also unable to get the 6" thick batts, so I ended up getting 3" batts with the intent to double up on them... :evil: In my case I've been toying around with the idea of using both fiberglass and mineral wool as my insulation -- mineral wool in the ceiling, mineral wool in the corners and at the halfway point along my long walls in complete fill fashion so as to make a very good fire break, which will use up what I have already purchased -- and then the complete fill cheap fluffy stuff the rest of the voids. I hope this information is helpful to you in deciding between the two types of products. --Keith :mrgreen: