Why double gypsum in the ceiling?

[ZipLock]

I am planning to install a ceiling with plasterboard on steel studs. When reading on the plasterboard manufacturers' websites, you get the impression that double plasterboard is the most common and they only mention single plasterboard in exceptional cases.

I can see the following advantages of single plasterboard:
+ Half the cost of board material
+ Half the work to transport and install
+ Half the weight

Now there must be disadvantages as well, so does anyone have input on why I should choose double plasterboard instead?

 

[MathiasS]

Soundproofing.

 

[TobiasGren]

One downside of single drywall is that the drywall manufacturer loses money ... sorry, I couldn't resist!

I think it sounds very strange with double drywall... I've been involved in several constructions, and none of them have been graced with a ceiling consisting of double drywall.

 

[TobiasGren]

Sound insulation.

Then I would think it would be better to insulate the intermediate floor/attic floor to achieve good sound insulation.

 

[MathiasS]

It doesn't provide much as far as I understand, but both are surely a good idea if you want quiet...

 

[JOW]

To vibrate a heavy mass requires more energy than to vibrate a light mass, thus if the weight is increased, the sound/vibrations decrease, and the frequency range for resonance is altered.

The insulation absorbs sound waves inside the floor cavity and converts it to heat (albeit incredibly little), the air pressure pulsations vibrate the insulation and the energy in the sound wave is reduced and converted to kinetic energy in the insulation.

 

[mycke_nu]

Another advantage of double plasterboard is higher fire rating, but it is probably only relevant in garages where welding is to be done.

 

[Michael86]

First question:

Is there any floor above? As previously mentioned, it's typically in basement garages where additional layers/thicker plasterboard are needed.

A 13mm board has a fire rating of 15 minutes.

Regards

 

[ZipLock]

It is an apartment and above is a concrete slab and then the attic floor. Better soundproofing could be an argument, as it sounds quite loud when someone walks in the attic.

 

[Michael86]

Must be heavy feet and a lot of running in the attic

Double plaster probably does a little for the sound. What absorbs the most sound is when something is solid.
Have you framed down the ceiling? Otherwise, steel studs with some ceiling profile might be something to consider, and perhaps some soft dampening bands between the concrete and the stud. As little contact with the existing surface as possible. Of course, it must be able to hold up the construction.

Best regards

 

[ZipLock]

Must be heavy feet and a lot of running in the attic

The attic has no inner floor, you walk directly on the concrete slab. Strangely enough, it seems as if some neighbors like to reorganize their attic storage late at night.

Double drywall might help with the sound. What absorbs sound the most is when something is solid.
Have you lowered the ceiling? Otherwise, perhaps a steel frame with some ceiling profile is worth considering and maybe some soft dampening bands between the concrete and the frame. As little contact with the existing surface as possible. Naturally, it must be able to support the construction.

I was thinking of something like this:

http://www.norgips.se/Konstruktionsprinciper/1

Steel studs attached to sound brackets and then one or two layers of drywall.

The question is if some insulation should be added at the same time?

 

[Michael86]

Absolutely, a little insulation shouldn't hurt.

Here might be something worth reading as well. It's more about walls, but the principle should be the same.

http://www.gyproc.se/gör+det+själv/så+här+gör+du/så+minskar+du+oönskat+ljud/påbyggnadsvägg

Edit:

Ceiling: http://www.gyproc.se/gör+det+själv/så+här+gör+du/så+minskar+du+oönskat+ljud/nerpendlat+tak