Second Storey Floating Floor on Joists

simonstav · Post by **simonstav** » Tue Sep 02, 2003 8:59 pm

I am looking to construct a studio on the second storey of a new tilt up building. As I am limited for height I was thinking about floating the entire floor using neopreme rubber under the sheets of ply and on top of the joists, then construct the walls and ceilings on the floated? floor. Does this sound feasable? The bottom of the flooring joists(ceiling of lower storey) would have 16mm (5/8") firecheck plasterboard mounted on resilient channel and rockwool in the cavity.

Regards Simon

giles117 · Post by **giles117** » Tue Sep 02, 2003 10:25 pm

My 1/2 a penny

Is there a major need to "float" this plywood?

Based on what you are constructing, I'd just isolate the walls and triple layer the floor for stiffness.

Plywood/Drywall/Particleboard

and keep doing what you said afterwards, rockwool in the cavity with a drywall ceiling below. You will get more than enough isolation.

I See no reason to "float" the floor as you are suggesting.

and the 3 layers will make the floor quite stiff for your needs.

Bryan Giles

simonstav · Post by **simonstav** » Tue Sep 02, 2003 10:34 pm

My main concern is isolation between control room and studio but I see what you are saying about stiffening the floor.

Regards Simon

giles117 · Post by **giles117** » Tue Sep 02, 2003 11:09 pm

A Floor Plan would help.

And if this is the case, I'd just float the live room floor.

But to add, start by placing 2x4's (wide side down) floated on top of the joists (perpendicular to the joists). Then the flooring material as I layed out earlier.

I'd go 16" O.C. with the 2x4's. With this, you'd lose about 1.75" in your height.

Bryan Giles

knightfly · Post by **knightfly** » Wed Sep 03, 2003 5:18 am

Simon, before we get too carried away with floating, etc, it would help (besides the floor plan Bryan mentioned) if we knew what the conditions are around your room(s), including outside sound levels, expected inside sound levels (thrash metal drums, dig's, Fijian Bamboo drums being struck on the floor, or just flute and acoustic guitar, etc)

Here in the US a "tip-up" means all concrete construction, where they pour all floors, walls, etc, in a single stack of slabs and then use a crane to "tip up" the walls, etc. Is that pretty much the case with you, or different? Specifically, is your floor ALSO concrete, and the joists you mention poured concrete, or are they wood or steel? What about the existing walls, exactly how are they constructed and with what?

All these details are going to have an effect on isolation, since they contribute one way or another to panel stiffness, flanking noise, structural strength, and acoustics.

You're right about isolation between CR and tracking room(s), but keep in mind the "weakest link" axiom. There is no point in building rooms whose walls, floors and ceilings are good for 70 dB unless you're willing to spend a small fortune on glass and doors. Even a control room glass that uses thick, dissimilar laminated glass and costs $9000 USD, will weaken a competently built 60 dB wall. John's preference of double sliding glass doors, if chosen well and installed correctly, would probably not exceed 50 dB by themselves, if not for more air in the form of a longer path between CR and tracking room.

If, however, you have neighbors below you (or a wife that sleeps while you record) or even neighbors alongside you, then floating the floors and floating the walls on those floors, and suspending ceilings resiliently, etc, will keep the neighbors from either calling the cops or poisoning your dog

-

This is at least partly because by floating everything, you cut down quite a bit on flanking noise. If you don't induce your sound into the concrete and framing of the whole building, it won't get to the next area by traveling through structure.

So, besides a floor plan, if you could clarify your situation based on the above, it will be easier to help you figure out what you really need vs. what you may not want to bother with... Steve

simonstav · Post by **simonstav** » Wed Sep 03, 2003 8:12 pm

Simon, before we get too carried away with floating, etc, it would help (besides the floor plan Bryan mentioned) if we knew what the conditions are around your room(s), including outside sound levels, expected inside sound levels (thrash metal drums, dig's, Fijian Bamboo drums being struck on the floor, or just flute and acoustic guitar, etc)

Sorry I should have been more specifiic. Not to much outside noise, light industrial area, mostly vehicle detailers/dealers yard and vehicle fit out yard. Crumpet bakery over the road, they get a truck load of flour once a week. I mostly expect to be recording rock/alt. rock.

Here in the US a "tip-up" means all concrete construction, where they pour all floors, walls, etc, in a single stack of slabs and then use a crane to "tip up" the walls, etc. Is that pretty much the case with you, or different?

This is what the building is. 6" concrete walls on four sides, iron roof and concrete slab floor. Second level will be steel main support beam through the middle of the building with timber joists. Flooring would be timber.

Half of the second level will be studio the other half apartment. I plan to put a dividing wall between the two with 3/8 firecheck/resilient channel on both sides lined with rockwool. The studio would then be contructed in an area of about 40 x 30 feet.

I planned to float the floors and then build the walls on the floated floor. Roof height is approximately 8ft sloping up to 10ft over the 30 foot width of the room. I could do as suggested; lay the flooring on the joists then lay 4x2 on rubber and on their sides with the next flooring on top. I would probably prefer to float all rooms.

Anyone calculate the weight of their studio rooms? My control room would probably be 18 x 18 and the recording room would be 27 x 18.

Regards Simon

simonstav · Post by **simonstav** » Wed Sep 03, 2003 8:57 pm

Here is a layout of the second level space available.

Regards Simon

giles117 · Post by **giles117** » Wed Sep 03, 2003 10:12 pm

Ok, so in plain ole english when it is all said and done, this construction is no different than a house with an above ground/walkout basement(with the second level added/a steel beam down the center/ wood joists.

I Know this is an oversimplistic explanation (don't write me no letters!!!) But it gives me a proper pic in my head.

Float the floor like I said. You'll be cool.

Especially seeing as you are also using a portion of it for living. This will help keep some of the "stomping" vibrations down so the living space can be enjoyed during a recording. I'd do 5/8" Firecode Drywall Instead of 3/8" that extra. Resilient channel only on ONE side of the wall. I suggest the apartment side. That will add a few more db's of isolation between the apartment and the studios (mainly enjoyed by the apartment dweller)

Just to clarify, you said dividing wall? Is that another wall between the studio wall and the apt wall? If so, Read all around here. Steve and John recommend you do not do that. Just the two walls of the apt and studio, and the rockwool lined airspace between them.

Finally, ultimately it is your labor and your money.

I took the dive and floated both of my rooms. People jump up and down in the hallway and I don't feel it in my control room. I am happy cuz that can be distracting. And I floated my Live room because I had done it previosly for another person and we got a great kick drum sound versus an unfloated floor.

Honestly, unless you hire someone to do it, the cost is not IMO substantial. it cost me about $300 to float my floors. What a small pittance for my comfort and enjoyment of what I built.

simonstav · Post by **simonstav** » Wed Sep 03, 2003 10:23 pm

Especially seeing as you are also using a portion of it for living. This will
help keep some of the "stomping" vibrations down so the living space can be enjoyed during a recording. I'd do 5/8" Firecode Drywall Instead of 3/8" that extra. Resilient channel only on ONE side of the wall. I suggest the apartment side. That will add a few more db's of isolation between the apartment and the studios (mainly enjoyed by the apartment dweller)

5/8 is what I meant, 16mm for me. The apartment dweller would be me.

Just to clarify, you said dividing wall? Is that another wall between the studio wall and the apt wall? If so, Read all around here. Steve and John recommend you do not do that. Just the two walls of the apt and studio, and the rockwool lined airspace between them.

Between the studio and the apartment I had planned for one 2 x 4 studed wall with 5/8 plasterboard on each side, one side on resilient channel.
Then in the studio the rooms would be individual rooms within the main room. ?

Finally, ultimately it is your labor and your money.
I took the dive and floated both of my rooms. People jump up and down in the hallway and I don't feel it in my control room. I am happy cuz that can be distracting. And I floated my Live room because I had done it previosly for another person and we got a great kick drum sound versus an unfloated floor.

I figured I'd might as well do it properly the first time.

Regards Simon

knightfly · Post by **knightfly** » Thu Sep 04, 2003 1:14 am

Sounds like you're on your way, Simon - I can't think of a thing to add here... Steve

giles117 · Post by **giles117** » Thu Sep 04, 2003 11:38 am

Well the only other thing I'd add is...

Have Fun

Bryan Giles

Post by **John Sayers** » Thu Sep 04, 2003 2:02 pm

AhAh - it's only just started - the design of the control room and the studio comes next:):)

cheers
john