Install a river-rock shower floor to give your shower stall the look and feel of natural stone. Whether you are renovating your entire bathroom or just the shower, river rock, with its overall neutral color scheme, complements many decors. Do-it-yourselfers with little tiling experience may want to practice their tiling and grouting technique on a different surface before tackling this moderately challenging project.
Set the Thinset
Begin tiling after all of the plumbing for the shower floor is complete and you are left with a clean, dry concrete base that is free of dirt, mildew and other foreign contaminants. Check to see that the floor slopes at least 2 inches toward the drain.
Spread thinset across the concrete base. Thinset is an adhesive used to set tiles in a thin layer of mortar. Look for a good quality thinset at a specialty tile store. There are many manufacturers, and each offers several product lines, often according to geographic regions. Ask a knowledgeable contractor or tile specialist in your area for a specific recommendation. Choose the right adhesive to avoid problems in the near future.
Start in a back corner of the shower and work in increments of 3 square feet or less. Do not spread more thinset than you can use before it dries, usually 10 to 15 minutes. Scoop the thinset out of the bucket and onto the shower floor. Use the flat side of a ¼-inch notched trowel to spread it. Hold the trowel at a 45-degree angle with the notched side down and drag it across the thinset to form neat rows of ridges.
Add River Rock
Place the river-rock tiles on the thinset. Retailers sell river rock tile mounted on 12 inch by 12 inch sheets of interlocking mesh. The advantages of these tiles are that the stones are spaced properly, it is faster to set the tiles and it is easier to see patterns across the tile.The tiles come in an assortment of colors. Some tiles will try to mimic the diversity of a river bed, while others offer monotones of gray, white, black or brown. Cut the tile backing to create shapes or patterns by mixing tiles. Alternatively, use individual stones. This method consumes more time and effort, but increases artistic options.
Press the river rocks gently into the thinset. Ensure that each stone makes contact with the thinset across its surface. Do not press the rocks past the thinset onto the concrete underneath.
Seal, Grout and Seal
Seal the natural stones with a penetrating sealer. Cover the stones with grout. Press the grout down between stones. Let the grout dry for 30 minutes. Use a stiff bristled brush to remove excess grout. Use a clean damp sponge to remove the grout from the surface of the tiles. Apply a second coat of sealant.