Using Mosaic Tiles in a Wet Area

Mosaic tiles are popular and look fabulous in showers and tub surrounds. If installed correctly they should last for several years! Too often I see contractors and customers trying to take short cuts to save time and money by skipping key steps that insure there will be no eventual leaks.

By taking the following steps your shower should last for years to come!

Using Proper Tile Board

You shouldn't use standard drywall in a wet area. It is not meant to be exposed to the extreme humidity and moisture that is produced in the bathroom. Instead I recommend using a product called Denshield. Most major tile shops or home hardware stores will carry this product. It cuts easy and is up to building code in Canadian Provinces and American States. Make sure that the seems are tight between each sheet and that it is well secured to the studs. You should also use a water proof cement between seams. Simply apply a layer of drywall fiber mesh over the seem and then add a layer of the waterproof cement over the tape with a flat edged trowel. This will lock up the joints between each sheet of Denshield.

Adding a Waterproof Membrane

What is a membrane? A membrane is simply an extra layer added between the wallboard and tile that insures no water will penetrate the wall. When installing mosaic tiles I cannot begin to tell you how important this is. Firstly, grout is not 100% water resistant. There's going to be hundreds of grout lines in your mosaic tile shower surround. You need to make sure that if any water penetrates the grout that there is something in there to add extra protection. If you add the membrane this will give you peace of mind for years to come.

RedGard:

RedGard is a roll on membrane that you can apply with a paint roller. It rolls on pink and drys red. When it dries it has the consistency of rubber glue. You should apply to coats of redgard. It takes about 2 hours to dry between coats. For the average home owner this is a good option! It is inexpensive and easy to do.


Schluter Kerdi Membrane:

Schluter Kerdi is a German product. It's an orange fabric membrane that goes on with non modified thin set. It's almost like wall papering. Getting it on flat and clean can be tricky. It does an excellent job and is warrantied if installed correctly. This is probably a job I would leave to a professional.

Caulking the Seams

One of the biggest mistakes home owners make when they tile a wet area is not using caulking where walls meet each other or the bath tub edge. When your house goes through seasonal temperature changes the walls expand and contract. Therefore hairline fractures can form in grout lines in the expansion joint. In other words the two walls may pull in opposite directions cracking the grout. Rather than using grout in the corner use a waterproof caulking that matches the colour of your grout lines. Any tile shop or hardware store will sell a good selection of these coloured caulking's to match the grout of your choice.

Secondly, you need to apply a sufficient caulking line between the tub and tiled wall. When you stand in the tub or shower pan your body weight is putting stress on the pan or tub which pulls it away from the tile ever so slightly.

When applying caulking I recommend running two lines of tape to form a nice even line. Apply the caulking and smooth it over with your finger. You should then remove the tape immediately.

Sealing the Grout

Sealing the grout lines is important for two reasons. The sealer locks up the porous nature of the grout. It doesn't make it 100% impervious to water, but it does help.

Secondly, sealing the grout helps make it resistant to stain. Everyone know soap scum and minerals in water stain your tub. It has the same effect on grout! If you add 2 or 3 coats of sealer 24 hours after the grout has cured it will help with these two issues. In fact, I would suggest adding a coat of sealer every year to keep those grout lines nice and clean. Since we're talking about grout here's another important suggestion. If you are installing glass mosaic tiles you really need to make sure you purchase a non sanded grout. Sands in grout can scratch the glass. You don't want to wreck your hard work with big scratches up and down your new glass walls!

Last, but not least! When you install your fixtures I suggest adding a clear waterproof caulking line around shower dial and flanges that sit flush with the wall. You don't want water getting behind these. At this point you should be done and ready to giver your new shower or tub a test run!

I hope these suggestions help get your project off to a good start! Make sure to follow the steps above and read the manufacturers instructions. This article is not meant to replace the manufacturers instructions! If you feel uncomfortable with these steps you should hire a professional.

Colin Wharton
www.covefinishings.com
1 888 408 1688 ext 1