Can we frame directly to the concrete slab?

jahluv supreme · Post by **jahluv supreme** » Tue Jul 20, 2004 8:43 am

Hi all.
Before anchoring our first wall we wanted to get your opinion on whether or not we should use sheetbloc rubber underneath our 2X4 wall sills? No rooms will be floated except for the control room which will get the usual 1/2" rubber (60 duro) neoprene pucks to decouple the floor joists from the common slab.

Due to our extrememly limited budget the iso booth and live room will just use the concrete slab as the floor. Will decoupling the 2X4 wall sills from the slab yield us any noticeable results? How much flanking can we expect from the concrete floor through the walls if do not decouple them from the slab?

I ihave seen some designs here with the 2X4's anchored directly to the concrete slab without any rubber. Any inexpensive alternatives? We do not have neighbors below. We are on the ground floor.

Sheetbloc is commonly used in walls for limp mass but is also used for decoupling 2X4's from the floor.

Many thanks,
Chris

z60611 · Post by **z60611** » Tue Jul 20, 2004 11:23 am

You might want to glance through this, paying attention to Eric's and Rod's comments most of all. In these links I think it's a basement concrete slab (over earth/dirt). http://forum.studiotips.com/viewtopic.php?t=779
http://www.recording.org/postlite17183-.html
http://www.recording.org/postlite20111-.html

AndrewMc · Post by **AndrewMc** » Tue Jul 20, 2004 5:45 pm

If it's soundproofing to the outside world that is your biggest focus then I wouldn't worry about floating the floors too much. I don't have any floating floors and the sound isolation is pretty much as good as anybody could ever ask for. I could have a live band play at 4am in the morning and the only thing you'd hear outside is the birds chirping.

I anchored the walls into the concrete slab with bolts, but I did put some pipe wrap insulation under the sills and a lot of caulk.

knightfly · Post by **knightfly** » Thu Jul 22, 2004 11:59 am

What about sound coming IN, are your upstairs neighbors quiet or picky? Are you using any resilient mounting for your inner leaf on those 2x4 frames, or are they separate frames from the outside structure?

The more details you can provide, the closer to reality we can get... Steve

Hi Def · Post by **Hi Def** » Fri Jul 23, 2004 6:21 pm

AndrewMc wrote:If it's soundproofing to the outside world that is your biggest focus then I wouldn't worry about floating the floors too much. I don't have any floating floors and the sound isolation is pretty much as good as anybody could ever ask for. I could have a live band play at 4am in the morning and the only thing you'd hear outside is the birds chirping.

I anchored the walls into the concrete slab with bolts, but I did put some pipe wrap insulation under the sills and a lot of caulk.

Hey Andrew...Pardon while I butt into the conversation! I am so confused as to the different opinions on floors. I've read that you need to float the floors for ultimate isolation. Both between the internal rooms as well as the outside world. Is this really true?

Are your internal room walls and floors sharing the same slab as the outer walls? How is your isolation between rooms? What are your walls made of. What kind of music are you tracking this early? Please advise as this could be a major cost savings, avoiding the floated floors. Thanks a million!

M

jahluv supreme · Post by **jahluv supreme** » Sat Jul 24, 2004 2:00 am

Hello Gentlemen,
Thanks for the helpful thoughts. Since neoprene is so pricey I was hoping to avoid floating the wall sills. Our main concern is to get the best isolation between the rooms and the neigbors to our left. What if we only floated the inside walls?

knightfly wrote:What about sound coming IN, are your upstairs neighbors quiet or picky?

Thankfully we do not have neighbors upstairs. It is a warehouse with units flanking ours. They all appear to be on the same concrete slab.

Are you using any resilient mounting for your inner leaf on those 2x4 frames, or are they separate frames from the outside structure?

We are planning on building seperate frames.

The more details you can provide, the closer to reality we can get... Steve

There is a steel garage door that we are currently boxing-in, stuffing and sealing that is on a poured concrete wall (about 16 inches thick). This box is will be built off the poured concrete wall and is touching. We plan to build a seperate second wall around this one which will be decoupled with neoprene. Does this create a three leaf situation?

The garage door is our main problem in terms of sound leakage from the outside world. The current ambient noise floor is quite good clocking in at 35db. Once the garage door is boxed and sealed we will take another measurement to see what we are up against. So far we are quite impressed with how quiet the space is in it's current state.

We want to put most of our budget into the control room so the least we have to do in the live room the better. One neighbor is a contractor and doesn't mind the music and the other neighbor is a mailing service that works 9-5 M-F. Our only concern is to keep our mail neighbors happy. When measuring pink noise (90db) from inside of their unit we came up with a reading of 40db. The wall was a solid 50db STC. Score!

If we can get away with it we will not build another wall...Perhaps buy them a boombox so they can't hear us.

We will float the drums and guitar and bass amps when recording those instruments which will hopefully reduce flanking through the floor.

Any thoughts?

AndrewMc · Post by **AndrewMc** » Sat Jul 24, 2004 5:43 am

Hey Andrew...Pardon while I butt into the conversation! I am so confused as to the different opinions on floors. I've read that you need to float the floors for ultimate isolation. Both between the internal rooms as well as the outside world. Is this really true?

Are your internal room walls and floors sharing the same slab as the outer walls? How is your isolation between rooms? What are your walls made of. What kind of music are you tracking this early? Please advise as this could be a major cost savings, avoiding the floated floors. Thanks a million!

M

Certainly floating the rooms on individual floors is going to give you better isolation - so yes that is true.

My internal walls share the same slab as the external walls. The walls are standard double walls - double layer of 5/8 drywall on the walls. My external walls do not have drywall on - it's OSB sheeting - so I caulked the studs, put in a double layer of heavy roofing felt between the studs, well caulked, then a layer of 5/8 drywall between the studs - well caulked. Cavity filled with insulation. The air gap between the studs is around 2" plus the depth of the studs - so total about 9". Some of my internal walls are inside out walls - so in this case the air gap is smaller.

I'm not tracking anything yet - but am playing music in the live room. Rock & Roll - drums loud guitars bass etc. Isolation to the outside world is close to perfect. Isolation inside the building is less perfect but still acceptable - the main weakness between rooms is the 2 sliding glass doors - even if the floor was floated I doubt it would be much better.

So in summary - if you can float the floors - do it, it can only make it better, but cost - benefit may lead you to not float the floors.