Designing Kitchens and Bathrooms - New Bathroom

I have just added a new bathroom in my basement, everything is going great, thanks to everyone in this Forum!! :-) Here is my questions. I have just finished all of the electrical and framing and I am ready to sheet rock. I have always used 5/8 sheet rock for the lid. My question: I was going to use 1/2 green board (Mostuire) sheetrock. This is okay correct? There should be no code saying it has to be 5/8 because there is no insulation and it is not on an outisde wall for the (Firetard code) Am I correct with this??

Thanks
Andy

Andy,

Building codes just about everywhere state that MR board should not be installed on ceilings. MR board is often recommended and required as a minimum for high humidity areas like your bathroom walls. If the walls were going to have ceramic tile placed, then using Durock would be the preferred choice. MR drywall is not recommended for ceilings. It would serve no purpose anyway, not much chance of moisture on the floor traveling up to the ceiling from within the drywall. Paint takes care of any moisture protection on a ceiling.

Although the USG book is a bit obscure, its the drywallers bible when it comes to drywall installation. (fire ratings, fastener placements, etc)

Using 1/2" is fine within the bathroom but go with standard drywall.

Remember, you must provide adequate air exchange (good exhaust fan) to control any potential humidity problems.

You can confirm this with your local building official.

Hope this helps!

Great. No MR on ceiling Thanks. Yes I will be using Durock for the walls which will be ceremaic tile. I have also installed a 100CM exhaust fan, yes I know it is way big for my size bathroom but, you can never be too protected when it comes to our little friend mostuire. :-) Thank you again for the information, Enjoy your weekend!!

Andy

http://www.buildtalk.com/Talk?13%40160.bobwaIF4jNC^0%40.ee6c8a6


http://www.coxlumber.com/gypsum.html

Water-resistant Gypsum Backing Board on Ceilings

For many years, the gypsum industry recommended against the use of water-resistant gypsum backing board (MR board or "green" board) on ceilings. This position was based on a concern that the materials added to the gypsum core to provide water resistance created a gypsum board that was slightly less resistant to sagging under conditions of high humidity. In recent years, the use additives have been fine-tuned to the point where this concern is less pronounced.

The industry has revisited this issue by conducting a series of tests to evaluate the sag resistance of modern water-resistant gypsum backing board. The results of these tests have found that modern water-resistant gypsum backing board can be applied to ceilings with confidence when the ceiling framing members are spaced closer together than the traditional 24 or 16 inches on center.

The sag resistance testing has led to the establishment of recommendations for the use of water-resistant gypsum backing board on ceilings which are published in Specifications: Application and Finishing of Gypsum Board (GA-216-96), and which are stated as follows:

Water-resistant gypsum backing board shall be permitted to be used on ceilings where ceiling framing is spaced not more than 12 in. o.c. (305 mm) for ½ in. (12.7 mm) thick water-resistant gypsum backing board and not more than 16 in. o.c. (406 mm) for 5/8 in. (15.9 mm) thick water-resistant gypsum backing board.