Durock (cement-board) versus sheet-rock ?

I was wondering if there were people who have used Durock or other cement-board in making their walls? Durock as opposed to standard sheet-rock appears to be much denser. 1/2 " Durock weighs 14.65 kg/M2 1/2" sheet-rock weighs around 8.35 to 9.3 kg/M2 (depending upon the type); 5/8" sheet-rock weighs about For my project, where ceiling height is at a premium, I'm considering at least using the denser Durock or some other cement-board in my ceiling layers. Should this not be able to satisfy 'mass' requirements? Indeed it would seem that if the same thickness is used (i.e., as if using 5/8" standard sheet-rock) then one could gain much more mass, AND increased density (which I'm led to believe accounts for something on it's own, regardless of total mass)

It's not a bad product, but it's more difficult to work with than drywall. It's heavier and can't be cut as easily. It's also a lot more expensive. It might be appropriate as an underlayment for stucco perhaps... But for interiors you're probably better off just using drywall -- lots of it. --Keith :mrgreen:

sharward wrote:

It's not a bad product, but it's more difficult to work with than drywall. It's heavier and can't be cut as easily. It's also a lot more expensive. It might be appropriate as an underlayment for stucco perhaps... But for interiors you're probably better off just using drywall -- lots of it. --Keith :mrgreen:

Ahh, the expense factor has not escaped my attention; and that may indeed be a major deciding factor. Yet, 1/2 inch of cementboard has 26 % MORE mass than 5/8 inch of sheet-rock (it has 70% more mass than 1/2 inch sheetrock!). Therefore, the cost factor in materials is NOT a direct comparison, since you will likely be using fewer sheets of cementboard than sheet-rock to get the same mass (although it still could be more expensive when priced by weight; this appears to be about 20% more cost per pound for cementboard). As for labor, although it's more difficult to cut, you would be putting up fewer sheets, so there would be less labor in that respect. It IS used indoors in kitchens and baths from time to time (I don't know how often, but it's use is not limited to outdoors). The other issue is the density. Density itself appears to be a factor in sound isolation that's independent of mass; i.e. denser things are better isolators it seems even when the total amount of mass used is equivalent (I did read this in a couple places). How much of a factor that is in this case, I don't know, but I wish there were someone who did know these things who would chime in. Also, if it were to save me 1 inch in ceiling height that may be of great value itself. (And if there were an issue of water, it's very water resistant when compared to sheet-rock.) K

Is it even suitable for ceilings though? :roll:

sharward wrote:

Is it even suitable for ceilings though? :roll:

I will have to find that out... Another issue I had just thought of (remembered seeing it in an article) is stiffness... It seems 'limpness' has an effect in relation to mass and density; very limp and dense (as in lead) seems to give a higher frequency resonance (with lead it would be supersonic if the lead were thin enough). The cement-board maybe very dense, but also hard (= stiff?), which could affect resonance (?).... K

bump for Knightfly.... thanx, K