"a practical hands-on
   guide to bathroom

Shower Wall Installation
Cultured marble panels (3/8" thick) in custom-made sizes or tile are the two most popular surfaces for shower walls.  That's what these instructions will focus on.
Installing cultured marble wall panels:
Cultured marble panels are normally made by local "mom and pop" shops and the quality can vary dramatically.  Work with an established shop that has the expertise to make good quality materials.  Request that lightweight filler be used - it's more expensive but easier to handle since it makes the panels lighter.  Many shops don't use lightweight to save on costs - if they don't and you have to haul a large panel without lightweight to a second floor it may be a challenge even for two people. 

Cultured marble panels are normally installed over new green drywall (mildew resistant) which is screwed into the studs (don't use nails since they can pull out).  It's best to tape and compound the drywall joints even though they won't be seen because it's the right thing to do.  Always measure twice and cut once since a mistake can be costly.  Keep in mind that most walls are not square - another reason to measure twice.  The green drywall should be installed to the tip of the lip on the shower base and the cultured marble panels should be installed to cover up the lip and "sit" on the shower base or tub. See Shower Purchase Tips for the importance of lips. 

If installing a recessed soap holder, determine where it/they are to be located and be certain that there are no obstructions like a 2" x 4", pipe vent, heat duct, etc. to interfere with the unit.  Also, keep in mind that some walls are 2" x 4" studs, but some areas 2" x 3"s or 2" x 4"s have been laid flat to gain space in the room.  Most recessed soap holders require a 3 1/2" depth for a proper fit.

After you are certain of the soap holder location, mark the panel for cutting.  I prefer using a china marker which is easy to clean off.  Cut the panels on a flat surface with 2" x 4"s underneath for support.  In hot weather cultured marble will bend and in cold weather it will crack, so in the summer keep it out of the sun and in the winter place it in a warm area
for a
hour or more before cutting.  Use a dry cut diamond saw blade for your straight cuts with a
tungsten carbide blade in a jigsaw for curved cuts.  Drill a 1/4" hole at the corners of the
proposed cuts to prevent possible cracking.  A good quality carbide grit edge hole saw

should be used for small holes such as shower arms or mixing valves. A fibre blade may be used in place of a dry cut diamond blade; however, the cut is not as fast or as accurate. 

We suggest using 100% silicone caulking as your adhesive to secure the panels to the drywall (wipe the marble dust off the panel to allow the silicone mastic to stick; otherwise, you will not get a good marble/drywall bond).  It should be "dabbed" onto the drywall and then the marble is carefully "forced" against it.

The open time for the silicone is very short (say 5 minutes), so time and accuracy of installation is important.  If a ceiling panel is to be installed, that should be done first. 
Ceiling panels must be secured with screws into the ceiling joists to prevent bending or falling.  The screw heads can then be concealed with snap-on buttons that are made specifically to hide the screw heads.  The back panel should be installed next. After the back panel is installed, then the side panels should be installed.  The side panels help keep
the back panel in plac
e.  Allow about a 1/4" or so space to allow the back panel to move as
it expands due to warm water
in the shower.  Your final caulking should also be white 100%
however, in certain color panels it's best to use clear 100% silicone (your choice). 

Avoid colored silicone since it's normally not as good quality as white or clear.  When caulking, the thinner the caulk line the better - a 1/4" joint is better than a 1/2" joint.  You may need to brace the walls for about 24 hours if they are out of square - that will give the silicone time to cure.  Protect the marble from your braces by using duct tape - it will prevent scratching the marble.  Always give the caulking 24-48 hours to cure before using the shower.
Installing tile on the walls:

Tile on walls should always be installed over cement panels.  The panels are usually in handy sizes (3' x 5' for example).  They should be screwed into the studs (don't cut corners and use nails).  Seams on all joints should be taped (typically with a perforated mesh tape) and then cemented for a watertight
seal.  Making the walls resistant to water is important and will eliminate the problems that occur when tile is installed on drywall.  The cement panels should be installed to the tip of the "lip" on the shower base and the tile should be installed to cover up the "lip" and sit on the shower base or tub.  See Shower Purchase Tips for the importance of lips. 

Installing tile on walls is done with a quality mastic for this purpose - or better yet with a thinset latex fortifie
d mortar.  If mastic is used, allow for a day or two curing time before
grouting the walls.  When grouting, never
use old grout (something that has been stored in
a garage or some old stock that a store is selling real cheap). 
Stick with name-brand quality
on any mortars, mastics and grouts and make certain they are fresh stock.  Glass tiles
require a special white
latex mortar and should be avoided unless the installer is experienced. 

Use tile spacers, available at tile shops, to keep the tile in uniform lines.

Accessories such as soap dishes should, if possible, be installed in place of a tile rather than making a hole in the cement board.  Avoid metal accessories unless they are solid brass or same quality product (you don't want them to rust - even the screws should be solid brass or stainless steel).

Wait 24 hours after grouting to caulk. When caulking, the thinner the caulk line the better -
1/4" joint is better than a 1/2" joint. Always use 100% silicone caulk - normally white is used.   

 Allow the new tile work to cure for several days before using the shower - the caulk alone
 needs 24-48 hours to cure.