Floating floor on fiberglass

[jtvrdy]

Hi,I'm starting to build a new studio it is on a first floor,the actual floor is conrete.
My first idea was to do a 10cm concrete floating floor on a double layer of compresed fiberglass+plastic sheet, but after checked with the architect it is not possible for the maximum load.He suggested me to put directly on the fiberglass two layers of 19mm MDF.
is this a good idea?

I serched and all that find about floating floor is to construct it on the 2x4 or 2x6 beams on neoprene pads and then the layers of MDF.

what advantages have each system?

thanks,

[knightfly]

Floating concrete on fiberglas would have nearly the same isolation as floating MDF on rubber and wood framing, if the cavities between frames are filled with mineral wool to dampen resonance. The concrete way will likely be more expensive, depending on your local material pricing.

There are also lightweight concrete available, and you may be able to use only 2-3 inches (50-75mm) which might get you down in weight so the fiberglas under concrete floor would work - you'd need to check with your architect on that part though.

Either floor would require a softer "perimeter board" installed and sealed to keep the floor from contact with walls

One advantage of the conrete over fiberglas method is more even loading of the structural floor. Just because your main floor is concrete does NOT always mean that it can take heavy "point loading" from spaced rubber pucks, unless there were footings poured in a specific pattern under the parts of the floor where the rubber supports need to go.

Consider too, whether your walls will be set on TOP of this floor or beside it - when specifying a floated floor all these things need to be accounted for. The combined weight supported can and will reach several tons... Steve

[jtvrdy]

I will chek the lightweight concrete thing...

I supose that is better to start the wall on top on the floated floor but what advantage(if any) have to start it on the original floor ?

[knightfly]

That would depend at least partly on what type of wall construction - the heavier the wall, the more support it needs. If that wall is resting on the floated floor, then you need to figure out your loading and support based on that weight as well as ALL the weight of EVERYTHING that will be on that floor.

These types of calculations are best left to an architectural engineer, preferably one with acoustics background - My own background is more general construction, followed by several years independent study in acoustics/sound proofing. This does NOT include more than a basic understanding of the physics of floated floors and walls, so exact calculations are not something I would be able to furnish.

Because of this, I would recommend that you include your architect in all phases of your design - just make sure he knows enough about flanking noise and sound construction not to cause any failures in your isolation system.

Just as a general rule, most people who float walls on top of their floated floors, use lightweight wall designs with gypsum wallboard and NOT heavy masonry walls.

I hope this helps; I don't want to give you the impression that I don't want to help, but I don't want to cause any problems due to overlooking any important details either... Steve

[rod gervais]

Listen to Steve carefully here regarding Engineer review of this - please do not assume anything, keep in mind that light weight is a relative term.

Standard concrete weights roughly 150 pcf........ lightweight is 90 to 120 pcf.

Lighter than concrete - but not light by any stretch of the imagination.

Thus a 3" topping slab (just the concrete alone) can add anywhere from 23 to 40 psf dead load to your structure.

You don't explain what this slab used to support - but you are talking about the possibility of adding a whole lot of weight to it.

Rod