John Sayers' Recording Studio Design Forum Archive

Not great pictures I know, but studs and ceiling joists for the entrance & shower room done, will block & morter the gable end and then dig out for the control room floor only 800mm deep to dig

Control room gable end sealed off am having a clear up then starting the dig out for the control room floor







Have been noticing on a lot of other builds that mod's are suggesting not to isolate the inner stud walls from the floor slab but to fix to the concrete floor I will be casting can some body give me a definite yes or no on this as I plan to concrete next weekend if things go well and then start getting the stud's up asap for electrical and HVAC 1st fixing after

could anyone answer the question in my previous post please?

Here's a picture of some progress of my dig out for the control room concrete slab, hopefully will be able to finish tomorrow and then concrete next weekend

Have been noticing on a lot of other builds that mod's are suggesting not to isolate the inner stud walls from the floor slab but to fix to the concrete floor I will be casting can some body give me a definite yes or no

I would check what your local building code requires or allows! Personally, where I live there is no choice: Earthquakes! BIG ones... Walls and floors should not move around in different directions, so they MUST be bolted together here. But your case might be different, so check with your local municipality / building inspector before doing anything.


- Stuart -

"Have been noticing on a lot of other builds that mod's are suggesting not to isolate the inner stud walls from the floor slab"

Well, you have two mods here, and neither of us suggest this. Matter of fact, the plate HAS to be fastened to the floor to resist the walls ballooning from all the weight and bouncing around the room ...so, your assessment that what "mod's" here are suggesting is incorrect since we have 75 percent of the active ones right here, right now.

xSpace wrote:"Have been noticing on a lot of other builds that mod's are suggesting not to isolate the inner stud walls from the floor slab"

Well, you have two mods here, and neither of us suggest this. Matter of fact, the plate HAS to be fastened to the floor to resist the walls ballooning from all the weight and bouncing around the room ...so, your assessment that what "mod's" here are suggesting is incorrect since we have 75 percent of the active ones right here, right now.

Many thanks for the clarification, but the way I read my original post I am asking if its ok to fix the plate down because I had wrongly thought that it had to be 'floating' or 'isolated' from the floor slab, I had not suggested that mod's were saying in other posts that the walls should be 'isolated', which seems to be what you are suggesting in your post, sorry if I'v misunderstood your above post, and again many thanks for your help it will be so much easier knowing i can fix the walls down

One other question, would I be better off filling all of the airspace between the inner stud and outer concrete block with acoustic insulation or just the 70mm stud then stapling netting to hold in place to leave a gap between the insulation and the outer concrete block work

Even if it is floated or decoupled in some manner, the fact is it will (the wall plate) have to be secured to the floor. That is not a step that can be removed in the hunt.

I have read many posts from many people here mostly and there is this lunacy that the wall plate has to be isolated.

What I have not seen is any thing that supports this thinking other than the basic notion that "it has not been shot down yet, and everyone else is buying into the idea".

Suggestions are based on a piece of neoprene or other rubber product, but I have yet to see the weight of an interior rooms walls/ceiling with all the sheetrock, etc, place a number on it and see where it lands.

It is not something that can be easily computed and in my opinion is not something that should have gotten this far into the language.

But there are far to many people that listen to far to many things that other people listen to since, by and large, no one owns a hammer and respects the "idea" since it is lofty in nature, and acoustics is usually the entry point to many for construction, but they think of it as something elite, which it is, but it isn't.

You still build things that work as a unit.

Not much data elsewhere to support this isolated wall, although I appreciate that it could help, I have yet to see any proof that suggests the effort and money spent actually makes it so.

It is not something that can be easily computed and in my opinion is not something that should have gotten this far into the language.

Absolutely! What the man said!

- Stuart -

xSpace wrote:Even if it is floated or decoupled in some manner, the fact is it will (the wall plate) have to be secured to the floor. That is not a step that can be removed in the hunt.

I have read many posts from many people here mostly and there is this lunacy that the wall plate has to be isolated.

What I have not seen is any thing that supports this thinking other than the basic notion that "it has not been shot down yet, and everyone else is buying into the idea".

Suggestions are based on a piece of neoprene or other rubber product, but I have yet to see the weight of an interior rooms walls/ceiling with all the sheetrock, etc, place a number on it and see where it lands.

It is not something that can be easily computed and in my opinion is not something that should have gotten this far into the language.

But there are far to many people that listen to far to many things that other people listen to since, by and large, no one owns a hammer and respects the "idea" since it is lofty in nature, and acoustics is usually the entry point to many for construction, but they think of it as something elite, which it is, but it isn't.

You still build things that work as a unit.

Not much data elsewhere to support this isolated wall, although I appreciate that it could help, I have yet to see any proof that suggests the effort and money spent actually makes it so.

Thanks for that Brien any thoughts on my insulation in the stud and air space?

The insulation is there for a reason, not for isolation, but to dampen the cavity and the panels. So you time is better spent making certain that the panels are damped. If they are then your job is kinda done. What you do not want to do is over-fill the cavity in such a way that the insulation becomes or creates a bridge that sound can move on basically a flanking path inside your wall assembly.

Thanks again Brien, so filling the air gap is better then leaving 50mm with nothing in and the studs filled as long as its not over filled tightly?


Managed to finish the dig out
Fingers crossed I can get prepped & concrete at the weekend, I would also like to say thanks to Glenn who suggested going deeper if possible to get as much ceiling height as possible, at first I thought no way but now I'v done the biggest part of the work below ground i'm sure it will be of great benefit.

When you pour your new slab, are you going to isolate it from the existing walls, or not?

Just a quick curve ball for ya...


- Stuart -

I was going to use a compressible foam that we use between walls and concrete etc, I have some 100mm and 150mm rolls of this, I am also going to put some 50mm styrofoam insulation under the slab purely for insulation , not for trying to create a floating slab, I was hoping that the compressible foam would be ok as it is what I use at work.

Some pictures from the weekend

isolation foam on top and side of foundations


1200gauge dpm with concrete backed styrofoam for damp proofing and some insulation



Ready for concrete



125mm thick concrete with Ronafix and reinforcing fibres added in the mix


Next I'm hopefully going to render during the week all the concrete block walls on there air space/cavity side with 4/1 render with fibres and water proofer in the mix this will seal the blocks in case of any perforations etc but also add more mass and strength.

Fibre reinforced render done on the air side of walls excuse the iphone photographs,









Expecting delivery of my caulk and backer rod from these guys tomorrow, ready to start stud work at the weekend can anyone confirm I have to put 3 lines of AC50 under the plates before fixing down?

http://www.sealantsandtoolsdirect.co.uk ... c50900box9