John Sayers' Recording Studio Design Forum Archive

Hello,

i have a few questions about the construction. It would be very nice if someone can answer these. Thanks in advance.

In this picture you can see my idea of building the floor and the walls.
My Questions are marked in Red & Green so you can see it directly.

Now my questions:

1. At the red "1?" you can see a material (I know for what it is, but my english is too bad to explain it.. ). What kind of should I use?

2. At "2?" you can see another Material. What kind of should I use?

3. Should I use sylomer under the new concrete Screed (You can see it. The red "Sylomer Pads")

4. Is it necessary to use a Sheet metal under the Metalframes to distribute the Load?

5. Is my construction ok? What should I take care of. Is it to complicated? can I make it easier with the same results?
The problem is, that i build my studio in a normal living area, so I have to take care of noise.....

Thanks in advance

Regards
Hendrik

I presume you've read Paul Woodlock's build thread at
http://forum.studiotips.com/viewtopic.php?t=107
He's probably the best person I know to answer your question.

. At the red "1?" you can see a material (I know for what it is, but my english is too bad to explain it.. ). What kind of should I use?

In this part of the world, 6 mil (thousandths of an inch) plastic is normally used for the water/vapoeur barrier.

2. At "2?" you can see another Material. What kind of should I use?

Again, in this pert of the world, 18 mm plywood, or mdf. check the prices in your area.

The http://www.kineticsnoise.com site has some good plans on constructiong floating floors.

That is the best I can do right now.

Good luck!
Andre

Hi,
thanks for your answers.

@z60611

I have read it. But till now not all. It is long...

@AVare

Yes, the "water/vapoeur barrier"...

Your answer at point 2:

Ok, above the Sylomer (the green horizontally line) is Plywood, but what is on the Side to the walls (The perpendicularly Green line)? If it were Plywood I will have a "Hard Contact"!

Is this also Sylomer or something similar?

Thanks in advance.

Hendrik

Greetings Hendrik

You should definitely read some more of my studio diary. There's a lot of detail about my floating floor ( plus piccies ) in there


Can I presume your building a room within a room? I wouldn't bother with such an elaborate floting floor unless you are.
And in which case you can simply the design a LOT by floating the WHOLE INNER ROOM on Sylomer BLocks,as Ihave done. This means you don't have fart about floating the walls seperately. Simply bolt them to the floating floor. Makes it a lot easier.


to your drawing...

1 is a damp proof membrane. Is is not postioned correctly in teh drawing. Only some of it is. I'll expalin later

2. is insulation material

You cannot pour concrete diectly onto the rockwool type insulation you need in a flaoting floor it will crush it, and render the floor useless.


Here's how to do it from original floor upwards to top of floating floor

1. Glue Sylomer blocks to original floor. Make sure the height of each block is within 1mm of each other. grind down the original concrete floor if necessary for blocks that are too high, and use shims above the block for those that are too low. Don't use any glue. The supplier fo the sylomer will recommend a glue tahts suitable. Sikaflex was recommended to me. You'll also have to prime the concrete before gluing the rubber to it.

2. Lay rockwool insulation on the original floor INBETWEEN the blocks to fill up the resultant airgap.

3. Then glue a layer of 3/4" plywood on top of the blocks. Use a strip of wood under the plywood edges so you can attach each 8 x 4 sheet together as one floor size monbloc of plywood. the plywood is there a formwork for the concrete.

4. then lay a damp proof membrane ( DPM )on top of the plywood. This prevents the wet concrete from soaking the plywood.

5. Then make your perimeter formwork, and place a 1/2" thick layer of polysterene against it, and cover with DPM again.

6. You're now ready to pour yoru concrete into the mould.

6.a you'll probably need a steel reinforced concrete slab. 1/2" rebar grid on 12" centres shoudl suffice. it's not expensive. The rebar sits on 'chairs'/'spacers' so that it's kept at the correct level ( the centre of the slab in my case ) whiel the cncrete is poured.

7, Pour the concrete, screed thte top of it, and wait 28 days before putting any weight on it.

8. The remove the polysterence perimiter layer,and you have a decoupled floatinf floor.

9. I took the oppurtunity to cast 12mm threaded studs ( to bolt walls to )into the concrete t oavoid drilling near the edges and cracking the concrete


A floating floor is bsically a mass(concrete)-spring(Sylomer)-Mass(concrete ) system. This has a resonant frequency. At this resonant freqeuncy you won't get isolation, you'll get amplification. Making things WORSE. So the idea is to design the system so the resonant freqeuncy is at least a coupel of octaves below the lowest frequency you want to isolate. 4 octaves is better ( btu nmore costly ).

I got mine down to about 9 to 10Hz.




Basically with elastomers like Sylomer, the more load you put on them ( upto a point ) the lower the resonant frequency. Sylomer comes in different stiffnesses to cope with different ranges of loads. The sylomer I used was Sylomer P. One of the stiffer varieties.

So first you must work out how heavy everything you put ion the sylomer is. INcluding heavy furniture, walls ceilings etc.

And then you can vary the load on each sylomer block why altering it's spacing. Of course under the walls the sylomer will be closer together. and after all two of the walls will also carry the ceilign weight.

For mroe info abotu designing elastomer flaoting floors go here...http://www.earsc.com/HOME/engineering/T ... asp?SID=61


The maths maybe possibly daunting at first, but read thruogh it all a few times and you'll soon get the idea. I then built a spreadsheet in excel with the formulas provided, so I could juggle all the parameters before finalising the design. Saved HOURS of work.

I must say in practise it's great having a floating floor. I haven't even sealed up my inner room yet ( no doors, etc ), but I turned my boom-box full blast to ear splitting volume inside the studio area a couple of days ago,a nd when I went outsie, I couldnt' hear a thing

Of course a boombox isn't no match for loud genelecs that are flat down to around 38Hz, but then I aint' finsihed the soundproofing yet.

hope that helps


Paul

Paul gave the best answer, but reading it over and over I could not find the answer to you queston about material on the sides of the concrete.

From I recall from the sides of the form are 3-6 mm thick plywood or a special material, that Kinetics sells.

To the best of my knowledge (not much!), if plywood is used, the thinner kind is prefered and just slipped into position square witht he floor. After the concrete is set, the plywood is removed and the perimeter sealed with acousitc caulk.

Someone please correct or confirm this!

Andre

AVare wrote:Paul gave the best answer, but reading it over and over I could not find the answer to you queston about material on the sides of the concrete.

It's in there. Read the bit about the polysterene facing the perimiter form

From I recall from the sides of the form are 3-6 mm thick plywood or a special material, that Kinetics sells.

To the best of my knowledge (not much!), if plywood is used, the thinner kind is prefered and just slipped into position square witht he floor. After the concrete is set, the plywood is removed and the perimeter sealed with acousitc caulk.

Someone please correct or confirm this!

Andre

Don't use plywood against the concrete. you'll never pull it out afterwards. Even if it's thin. Except when there's a large gap between the floating slab and the original walls. Then it's easy to build a plywood form taht's removable. I did this on 3 sides of my floor, but the third side there only a 1" gap between the adjacent floor and the floating floor, so I put in a 1" thick slab of polysterene covered in damp proof membrane before the pour. Once the concrete had hardened, I could easily dig out the polysterene with a large screwdriver.f

There's also no need to seal with acoustic caulk.

btw - the material on the sides of the concrete in the picture is insulation. Again not needed at the sides, but no harm if it's there, as long as it's rockwool type and not hard insulation that would wreck the decoupling

Hope that helps


Paul

Thanks Paul!

Andre

Wow!!!

Thank you very much Paul. Now I understand it and know how to built this Floating Floor.... Building the Walls on the Floating floor is a good point. Sometimes I think to complicated...

But I have 2 other Question... :

1. Is a 15 cm Concrete on the sylomer enough? I know I have to calculate the load to choose the right sylomer, but is it enough to build everything up (Walls etc.)?

2. How did you realise the contact between the walls and the ceiling, or did you build up the ceiling on the wall frame?


3. (perhaps Steve?) My building is a standard "Brick House" which means that I have a Brick - Insulation - Clay brick System as the Outer Walls.

Now, when I build up the inner walls (only these ones which stands parallel to the outer Brick), I have a 3 Mass System. Or not? How can I handle this?

Thanks that you help me.

Regards
Hendrik

Hendrik, in my part of the world there is very little brick construction, so I'm not really clear on what you have - is your existing wall actually TWO separate brick walls, with insulation between them? If so, are there "weep" holes along the bottom outer part of the wall?

Or, is your wall built with hollow-core bricks, and insulation in those hollow cores? Steve

Hi Steve,
here is a picture i´ve found in the net. This kind of construction is very common here. The rear stones form the basic wall, between them the heat-insulating layer and before it are the outside clay bricks.

This is a normal outer Wall construction of a house here.

If any of those bricks have hollow cores (can't tell from the picture) then you already have too many leaves - if the inner and outer bricks are both solid, you have a 2-leaf wall, and adding another leaf and air gap will decrease your low frequency TL while possibly improving your mid/high frequency TL a few dB -

Have you done any measurements of SPL on the existing construction, so you know what you already have? What about noise levels that are present in the area? Without knowing what is already there, it's not possible to even guess what needs to be done... Steve

Hendrik

We seem to have drifted up from the floor to the walls.

I'm not sure what your soundproofing goals are:
a) don't want to hear outside noise infecting the inside
b) don't want neighbours to hear some instrument
c) don't want wife/family to hear instuments/remixing

Although measuring db(c) is easy enough with a cheap SPL meter (e.g. radio shack's), breaking it down by frequency may be an entertaining experiment. For examples on the cheap,
1) I measured my furnace noise by plugging a microphone into my computer and using Microsoft Media Player.
http://www.bobgolds.com/Furnace/OLD/Fur ... se2004.JPG
2) I played loud semi-single-frequency tones in the room, and measured outside the room to see which frequencies were going through.
http://www.bobgolds.com/StcVsFstc.htm

Again, I'm not recomending this as being useful - you've already got your outside wall built. But it could tell you in numbers how much more you might want to add (e.g. none). And as a measurement it combines the effects of flanking and other directions other than just the wall. How to do it is another tale.

knightfly wrote:If any of those bricks have hollow cores (can't tell from the picture) then you already have too many leaves - if the inner and outer bricks are both solid, you have a 2-leaf wall, and adding another leaf and air gap will decrease your low frequency TL while possibly improving your mid/high frequency TL a few dB -

Hi Steve,
i want to make a new 50 m2 building on my existing House. This new studio building (green) has cóntact with one outer wall of my normal house (red) as you can see in the picture. So this outerwall of the existing house is my problem. All other walls I will build new, so I can build a one leaf Outerwall and my inner wall on the floating floor will be my 2nd leaf. But in this little area I Have probably a 3-4 leaf construction. How can I handle this?

btw. The picture you see above is not my house. It is an example of the probable construction of the house. It is an old house that I bought, so i don´t know it exactly.

knightfly wrote:
Have you done any measurements of SPL on the existing construction, so you know what you already have? What about noise levels that are present in the area? Without knowing what is already there, it's not possible to even guess what needs to be done... Steve

No, I have not, because the studio building is not built yet....

z60611 wrote: I'm not sure what your soundproofing goals are:
a) don't want to hear outside noise infecting the inside
b) don't want neighbours to hear some instrument
c) don't want wife/family to hear instuments/remixing

a,b,c. YES!!! I am planing a concrete floating floor on sylomer pads with 3 layers of Drywall on wall and ceiling. It must be as quit as possible. From recording room to Controlroom, from Studio to the house, from studio to the neighbours, and from the neighbours to the studio....

Regards
Hendrik

I see no doors yet - are you planning a separate entrance from the outside, or one between the house and studio?

Second, is it absolutely necessary that the section of wall be shared, or is it possible to build the new part completely free-standing? If you can separate the two physically, it won't help much with wall leaves (few dB better, but still some air coupling) but it WILL reduce flanking noise into the house (and vice-versa)

Third - if you're planning a floated concrete floor system, don't skimp on the base slab thickness - I would go at least 125mm, preferably 150mm base slab thickness with adequate reinforcing steel, and (check your local codes on this) at least 30 cm deep x 60 cm wide footers around the perimeter of the slab - this will vary depending on compressive strength of your soil, and local frostline. The point is, you will have approximately 8 TONS of weight spread out over the area of your floor if you put a 75mm thick floated floor(s) in your entire studio, plus the weight of whatever wall/ceiling/roof system you use - triple gypsum walls alone will weigh approximately 60 pounds per linear foot of wall if they are 8 feet tall, and masonry is heavier than that by quite a bit (concrete weighs about 3X what gypsum weighs) -

Let me know about your planned door location, and whether you can detach your studio or if it MUST be a common wall... Steve