Designing Kitchens and Bathrooms - New Shower Installation

I am preparing to install a new shower where a closet used to be. I understand that it is advisable to place #15 roofing felt between the studs and the cement board. However, there seems to be at least three grades of #15 felt. What is the difference and which is best to waterproof the shower?

Also, I was reading the list of the order in which a new bathroom should be installed, and noted the inclusion of insulation in the walls to reduce sound transmission. For inside walls, what type of insulation is best for noise reduction?

David Dickson,

You only need 15# plain roofing paper or 15# premium, I would go with the lighter one 15# plain. It's not as heavy in weight and you're not doing any roofing in the bathroom, I hope!

Insulation for "softening" the sound can be R-13 unfaced since a moisture barrier will be used.

Hope this helps!

Thanks again, Doug.

David Dickson,

You're very welcome and happy holidays to you and yours!

Merry Xmas!

Is 3/4" plywood good for backboard between metal studs for shower pan and grab bars?

David,

The issue with 3/4 plywood for backer for shower pan and grab bars is OK as long as a vapor barrier is placed over it prior to installing a cement board backer.

Let's assume that you are making the shower base and the walls/floor are tiled. Since you are using metal studs and you intend to use grab bars I will detail what I think should be used with tiled walls/floors.

When using metal studs and you intend to use grab bars, I would use 2x6 or larger wood and install edge up between studs, flush with the face of the stud, where you believe the grab bars will be placed. Plywood, even though it is 3/4" may not provide the strongest holding power and I am not a strong advocate of molly anchors. Nothing beats a good wood screw into solid wood.

I would then install a cement board over this for your tiled applications. You need to apply a cement board backer over anything wood or it will be destroyed.


Hope this helps!

Yes it certainly does help. Would you recommend using 4 mil plastic or 15# felt for the moisture barrier?

David,

I'm glad it is helping. You have a choice, whatever seems cheaper. If you have the plastic, even in 4 mil, go for it unless you need 15# felt for something else. I would do the plastic since you could use the excess for something else, like masking protection for the floors when painting.

Happy Holidays!

Two mor quickies, then I will leave you alone for a while! Is it ok to screw the plastic to the metal studs? Concern is puting holes in the plastic. How should I fasten adjacent sheets of plastic together? Is some kind of epoxy necessary or is there a better way?

David,

Got any duct tape? Overlapping sheets is fine.

This help?

Yes, thanks. And screws to studs are ok?

David,

You can screw the plastic to the studs, the plastic needs only a few screws to hol it in place, it should be fine. This won't cause any problems. You are placing this over the plywood right? Was that your intention?

On your advice, I will use the 3/4" plywood only behind the pvc shower pan at the lower part of the shower wall. Where I need grab bars, I will use 2x6s. Then the plastic, then the cement board, then the tile. I assume the plastic should extend down behind the shower pan on the lower part of the wall so there is no gap. Also, I assume that I will have to put shim strips on the metal studs above the shower pan to make up for the difference in thickness of the pvc.

David,

I have attached a link that shows the installation process for a pvc shower base. Please disregard the drywall they show and do what I mentioned in my previous posts.

You may apply the 3/4" plywood all the way down behind the shower pan then install the Durock as per the illustration - Note what happens at the shower base lip. The poly can be installed over the 3/4" ply then do the durock. NOTE: The Durock will take up some space within the shower pan but you final wall application will go down to the shower pan.

http://www.asbcorp.com/manuals/front-bib.pdf

DON'T FOREGET WHERE YOU INSTALLED THE 2X STOCK FOR YOUR GRAB BARS - MAKE A DRAWING AND PUT DIMENIONS ON IT.

Hope this better defines the process, sorry, should have sent this to you sooner.

Doug,

Thanks again for the help. I have looked at the reference you gave me. However, I plan to build the shower pan from sheet pvc rather than put in a preformed base. So I will try to adapt that information to my situation.

Here is a diagram of how I plan to construct the shower curb. Any suggetions?