New build

[Destt]

Hello all,
I am trying to convert a Anti Vandal Office into a small studio/practice room the space is 32ft x 10ft We are going to build a stud wall inside the room with a double layer of 15mm plasterboard on the inside wall and fiberglass insulation between the wales,
The floor will be rigid fiberglass with 2 layers of ply-board on top.
My question is, as we can not put down a concrete floor do you think I should mount the walls on a anti vibration pad of some kind, or just attach the to the cabin floor?
Thanks

[Gregwor]

Can you please read the forum rules and fill out your profile entirely? Thank you!

The floor will be rigid fiberglass with 2 layers of ply-board on top.

What is the floor made of right now? Is your room attached to a shared building or is it stand alone?

My question is, as we can not put down a concrete floor do you think I should mount the walls on a anti vibration pad of some kind, or just attach the to the cabin floor?

See my question above.

Greg

[Destt]

Hi Greg,
Thanks for responding,

The current floor is made of a layer of 6mm ply on a 15mm chip board on 15mm polystyreen on a 2mm steel

hole.jpg

The room stands alone about 50m from any other building

cabin.jpg

I have tried to draw up what we had planed for the construction

Room Side.jpg

room top.jpg

[Gregwor]

This all makes sense now. My biggest concern would be whether or not that existing floor can handle the weight of your inner leaf construction. The last thing you want is everything falling in on itself! I would investigate that further before you continue. As for design, I would beef up that floor with another layer of subfloor OSB. I agree now that partially decoupling the inner leaf floor by floating it on insulation would work. As for floating the walls, you'd have to do a lot of math to figure out the final weight of your inner leaf walls and ceiling and then find the perfect isolation products for that job.

Lastly, what are your plans for HVAC?

Greg

[Destt]

We have looked into the strength of the existing room and it can hold 2.8 tons (2840kg) so we think it should be OK.
I am getting the floor idea from Home Recording Studio: Build it Like the Pros Book by Rod Gervais, he talks about a "3 psf rigid fiberglass" floar with 2 layers of board on top, does anyone know if the floor just sit on the fiberglass board, or would it be supported on joists?
And does anyone know a source for the "3 psf rigid fiberglass" I asked about it at our suppliers but they are not sure. and in your opinion is it worth it, or should we just add more layers of board to the floor?
As for the HVAC, I am installing a split heat pump in the left and side of the live room, with a active extract and passive intake fed through a baffling box, probably have the extract on the back wall with the fan on the outside and the intake running down the length of the room in a flexible duct, to try and avoid the air short cycling.
Thanks

[DanDan]

You are 50M from any other building? So what level of soundproofing are you seeking to build?
DD

[Destt]

Just to a reasonable level, so I can practice with my band in the evenings.

[DanDan]

I recommend we put some science and numbers on 'reasonable'.
I suggest get an SPL Meter. All the iPhone ones I have tried were within a few dB of my proper SLM here.
Measure full range, i.e. Z or C weighting. I usually use Slow response to average over things a little.
But if your app has LeqZ go for 5 minute samples.
Measure at your neighbours. Let's see what the ambient background level is at the time you hope to practice.
It would be great if you have or could borrow or hire a powerful speaker system. Play representative music loud, up around 110dB or more. Earplugs! or Sealed Cans if you are stuck. Measure again at the same neighbour spots. Also take a listen outside your building. Find any audio leaks.
DD

[Soundman2020]

Hi there Destt, and Welcome to the forum!

We have looked into the strength of the existing room and it can hold 2.8 tons (2840kg) so we think it should be OK.

Wellll.... yes and no. Just because a floor can hold 2.8 tons does not mean that you can have four walls resting on it that total 2.8 tons... It's not that simple. A wall is line load, where all of the weight is concentrated on a very small area along a single line, basically. That's not the same as having the same weight spread out across many square meters all over the floor. You need to do some more figuring out here, to make sure that you can place heavy line loads on that floor. The only real way to do that, is to hire a structural engineer to come take a look at it. As Greg said: it would be said if you built a nice studio, then it collapsed the first time you used it due to structural overload.

"3 psf rigid fiberglass" floar with 2 layers of board on top, does anyone know if the floor just sit on the fiberglass board, or would it be supported on joists?

No joists! It rests ONLY on the fiberglass. If you put joists in, then you would totally bypass the purpose of the insulation, which is to decouple and damp the floor. So, also take care when you lay the floor on the insulation, that the wood does not touch the walls anywhere. The wood sits ONLY on the insulation and does not touch the walls or anything else. Leave a small gap around the edges, then later caulk that with a highly flexible caulk.

And does anyone know a source for the "3 psf rigid fiberglass" I asked about it at our suppliers but they are not sure

I think you mean "3 pcf", not "3 psf". Big difference! The "3 pcf" part means "3 Pounds per Cubic Foot", which refers to the density. That's roughly 48 kg/m3. "3 psf" is meaningless for insulation. psf measures pressure. pcf measures density. That's probably what confused the guys at your hardware store. Asking for "3 psf insulation" is sort of like asking for "3°C of bananas" at the grocery store...

Owens Corning OC-703 would be about right for that.

and in your opinion is it worth it, or should we just add more layers of board to the floor?

That method is not really a true floated floor, but it does help greatly with impact noise, as well as providing some effect for airborne sounds, so it's worthwhile. However, you are going to loose several inches of ceiling height like that.... can you afford to lose that?

As for the HVAC, I am installing a split heat pump in the left and side of the live room, with a active extract and passive intake fed through a baffling box, probably have the extract on the back wall with the fan on the outside and the intake running down the length of the room in a flexible duct, to try and avoid the air short cycling.

I normally prefer to bring in the fresh air at the rear of the room, and extract the stale air at the front. Also, do make sure that your air supply duct is directly above the mini-split indoor unit's air intake, so the incoming fresh air goes directly into the unit, for cooling/heating/dehumidifying before it reaches the room. It's a common mistake in many home studios to not do that, then the owner can't figure out why the air in the room never seems to be at the right temperature, even though the HVAC is running full bore....

Just to a reasonable level, so I can practice with my band in the evenings.

As Dan said, you need to put real numbers on that. What one man considers to be a "reasonable level" might be considered by another man to be "screaming hell"... and the cops might have a different opinion too! Get yourself a simple hand-held sound level meter, and do some testing to find out how loud your band is, and how quiet you need to be to meet the local legal noise regulations. If you don't meet those, then everything you do is wasted. The cops will show up on your doorstep and shut you down.... as well as possibly fining you.

It's important to identify how much isolation you need, in decibels ("transmission loss"), and design your isolation system to produce that amount of isolation. A typical band can easily put out 115 dBC, and noise regulations likely impose some kind of ridiculously low limit, such as 35 dBA, so it's important to do the research and the testing to make sure that your studio actually will do what you want it to do. Just as sad as having it collapse under your feet, would be to have it shut down by the cops the first time you use it, because it isn't isolating enough. Almost as sad would be over-building it, wasting a lot extra time, money, and effort on getting more isolation than you need (however, that practically never happens! I've never heard anybody say "my studio isolates too much".....).


- Stuart -