Concrete perimeter wall

Yiannis · Post by **Yiannis** » Sun May 16, 2004 8:13 am

Rod,
you are right about that foam.Sorry I forgot to mention.

What I don't understand is why the roof should be ventilated if it is air tight.Or it can't be air tight!

If the roof can't be use as the outer leaf for the isolation then it's no reason to use ceramic tiles because are expensive.

I mean I can use a simple roof for protection only, as Steve mention, and then construct 2 leafs.

thank you

knightfly · Post by **knightfly** » Sun May 16, 2004 11:52 pm

Yiannis, you are seeing why we like to have long, drawn out conversations with members before making final suggestions as to ways of doing things - in your last post, you mentioned that it would be no use to have the ceramic tiles if that roof wasn't going to be the outer leaf, which (as you rightly pointed out) it couldn't be one of the leaves if it's ventilated -

My understanding of your idea just improved a lot with that statement - the answer is, you can't have both - either the roof is part of your sound proofing and is airtight (needs insulation where Rod stated or major condensation problems) or else you do as you stated and build the two leaves and use the (ventilated) roof just for weather protection.

Personally, I think there are much cheaper ways of doing a heavy outer mass leaf than using ceramic tiles - unless you just like the way they look, I think you could do better from a performance standpoint - for example, a reinforced concrete slab with cast-in rafters would have higher mass than ceramic tiles (unless they're 150 mm thick) and therefore give you better Transmission Loss at all frequencies - then, any relatively inexpensive roof would serve as weather protection, and your sound isolation would not be compromised.

Part of your decision may be swayed by architectural design, too - if the rest of your place has ceramic tile for roofing, you may want to continue the theme, etc - the more info you give, the better our understanding of your situation and the closer we can come to a plan that works for you... Steve

rod gervais · Post by **rod gervais** » Tue May 18, 2004 4:18 am

I tried to add something yesterday - but the site wouldn't let me log in - so will try today.

Even if you add the insulation (which WILL take care of any condensation issues) the proposed roof is not going to be (IMHO) a very good outer leaf for sound isolation purposes.

In order for a system to work properly it's needs a number of things as a part of it's construction.

Mass

Sealed Joints/Seams

Structural Isolation.

Etc.........

Your outer covering may work from the point of view of mass - and structural isolation (if you build a room within a room) but it will not meet the sealed joints / seams requirement.

The joints on the roofing - both horizontally as well as vertically will allow the easy passage of air currents - and thus sound.

Effectively the bitumen barrier will wind up being your true sealed barrier -

So although you might get some benefit from the added mass - I do not believe you are going to re-coup the added costs involved.

Rod

Yiannis · Post by **Yiannis** » Wed May 19, 2004 1:39 am

Steve,Rod
I think that finally the ceramic tiles roof will be not constructed.
The reason is that it can't be a part of my insulation and 2nd its too expensive!
maby a flat roof is better.
I don't know if I can use a roof made from concrete.
Are there any proposes for roofs that I can use as the outer leaf of my insulation?
Except concrete are there any alternatives?

thank you!

knightfly · Post by **knightfly** » Wed May 19, 2004 2:59 am

Yiannis, you mentioned that the space you're using is already the roof of an existing building? What type construction is that roof?

It would help if we knew more about what is normal in your part of the world - it's possible that you may already have a solution that we can just add to... Steve

Yiannis · Post by **Yiannis** » Wed May 19, 2004 7:36 am

Steve,
The existing roof(my future studio floor) is made from 13.5cm concrete with irons inside.

Hope this helps.

thanks

knightfly · Post by **knightfly** » Wed May 19, 2004 8:23 am

OK, if this is strong enough to support your interior walls, etc, why not just duplicate that construction for your outer ceiling's mass layer? Is the existing roof flat, and then covered with a waterproofing covering, or what?

Acoustically, that would work fine for your outer shell - then an inner shell that's supported on the inner walls would round out a mass-air-mass system for you... Steve

Yiannis · Post by **Yiannis** » Wed May 19, 2004 11:30 pm

Steve,the existing roof is flat and waterproof.

take a look at this please

www.mdue.it/maneggevolezza_eng.htm

Maby is a good solution for my outer shell.
I have send an email and waiting for the STC numbers .

Its a sandwich panel with 12cm concrete in the middle.

The best is that there are no joins anywhere.Roof and walls are one!

Better to read it, you'll understand much more than I can describe in English.

thank you!

knightfly · Post by **knightfly** » Thu May 20, 2004 1:54 am

Yiannis, this is almost identical to the system I'm planning for my next facility - here in the US, it's referred to as "ICF", or Insulated Concrete Form, construction - I would estimate that if/when they give you an STC rating, it will be somewhere between 50-55 depending on surface finish.

If you do that for your outer shell, then build an inner shell such as we've discussed briefly, and leave a gap between the two shells of around 20 cm, I don't think you'll ever know that an airplain flew over if you're inside the studio. (This is, of course, assuming you pay particular attention to your entrance and use a double door, sound lock entrance)

Using that wall system, then a 20 cm air/insulation space, then a frame with two layers of 15mm gypsum wallboard, all properly sealed, calculates out to STC 81, with a transmission loss of 42 dB even as low as 50 hZ - a VERY respectable isolation performance for any studio, anywhere. A third layer of wallboard inside would gain you about 3-4 dB in every frequency band.

Good choice, my friend - this is the construction of the future, from what I've seen so far... Steve

Yiannis · Post by **Yiannis** » Thu May 20, 2004 2:28 am

Steve,I am very happy that my choice is acceptable from you.

Its the best choice for my outer shell and I think much lighter that the concrete blocks that I mention earlier.

Now my concern is about the stability of my house .I am waiting an enginner to check it.

I dont think that I will have a problem,but better to be sure before construction starts.

I will do everything you have advice me so far Steve and I am counting on your help and knowledge so my dream comes true.

Could I use one of these walls for separating the CR from the studio?
Of course with the addition of new walls on both sides.

thank you!

knightfly · Post by **knightfly** » Thu May 20, 2004 2:41 am

"Could I use one of these walls for separating the CR from the studio?
Of course with the addition of new walls on both sides." -

You could, but depending on materials available in your area you might find it easier to just do double-framed gypsum walls between the CR and other rooms - be careful you don't fall into the trap of too many leaves - 2 leaves and one air space is by far the most efficient use of material. Also, a double-framed gypsum wall would be quite a bit lighter, which may be a consideration for support from below... Steve

Yiannis · Post by **Yiannis** » Thu May 20, 2004 2:56 am

Steve,the only reason is that the engineer told me that he HAS to put some walls inside for supporting the roof.

I don't like that ,but what can I do?

I told him that I will construct new walls inside with my own rules

If finally I have to put this wall to CR my thought is M2 in the middle and single frame for each side of the wall which will have 3 layers of drywall all in one side. Mass-spring-mass right?If I wrote it correct!

thank you

knightfly · Post by **knightfly** » Thu May 20, 2004 3:34 am

The M2 wall would be one center of mass - you only want one more, so only one side should get a frame and wallboard, with all layers of wallboard being mounted on the same side of that frame. Fiberglass or rockwool insulation between, and you're set -

If you need interior walls for support, it should be the M2 stuff - you can then build the second center of mass as a non-load bearing, isolated wall. In this case, you would need to plan ahead enough to know exactly where your inner walls need to be, since at least part of them will be poured concrete... Steve

Yiannis · Post by **Yiannis** » Fri May 28, 2004 2:21 pm

Hi Steve,
I haven't start anything yet because I have some problems with local laws.

I can't do anything over 30-40 tons.The engineer said 40-50 tons...but I just want to be sure for the weight.
The M2 is too heavy for my house.About 80 tons for 100 m2.

What do you think about their single panel?I don't think it will do the job.

What is your suggestion for those perimeter walls?Is the load enought to handle good isolation?

thank you!

knightfly · Post by **knightfly** » Tue Jun 01, 2004 5:32 am

Yiannis, you can build lighter walls/ceilings with good isolation but it depends on what's available in your area - I didn't see enough information on the single panels on their site to tell what they are doing there, sort of looks like they're just using styrofoam with embedded wire so they can stucco one side?? If so, that would be not too good for sound by itself - under the right curcumstances, though, using that as an outer leaf and multi-layer gypsum for inner leaf could work. 8 foot tall gypsum walls with 3 layers of 15mm will weigh between 65 and 80 pounds per lineal foot, and if you were to use a fairly large air/insulation gap you could still get pretty high sound isolation - the low frequencies would be hardest, that's where the wider air gap would help.

Can you give me an idea of the types of materials that are available in your area for outside wall construction? Otherwise, I'm just "flying blind" here... Steve