Sign In to join the community | Help
Bath & Faucets

Installing a glass 3"x12" tile with mastic and grout to drywall?

Is it ok to install a glass 3"x12" tile with mastic and grout to drywall in a powder bath? The only place there will be possible moisture is behind the sink or in the occasional cleaning. My husband mentioned using a cement board first but neither of us are willing to cut into the existing drywall thereby creating an edge, which is fine if we must but I don't want the edge to be more than 1/4-1/2" thick when finished. Do they even come that thin? I have found that the mastic or pre-mixed ceramic tile adhesive will work instead of thinset but it's the moisture from the grout that is causing concern. Also, are there colored non-sand grouts available so that I can match it closer to the tile I have chosen?

Please help. We've never tiled anything before and want to do this correctly.

Thank you.
Not what you were looking for ? Try posting a question
Posted 2016-04-06T20:08:35+0000  by MAW MAW
Hello MAW,

Glass Tile Premium Thinset is rated by the manufacturer for glass tile.

Other mastics may turn your glass tile yellow.

My add-on suggestion would be to apply two coats of Zinsser Cover Stain over the drywall before you begin.

John at Custom Building Materials Technical Support suggests scuff sanding drywall sealed with oil primer and then using a damp sponge to remove any sanding dust.

He says, "This additional step ensures the mastic will adhere well to the primed drywall."

John also suggests you wait until the damp wipe dries before applying mastic.

The oil-based primer creates a barrier that blocks moisture from the wet mastic or grout from contacting the sheathing on your drywall.

Wet substrates are a common source of tile failure, so when applying tile over drywall, oil-based primer helps ensure your project will look great for years to come.

Once the wall is sealed, clean, and dry, use a one-half inch notched trowel to apply mastic.

Set tile and allow the mastic to dry at least 24-hours before applying grout.

You will find numerous colors of non-sanded grout readily available from your Flooring Associate.

After your grout dries, TileLab Sealer will prevent moisture from passing through the surface and will also prevent stains from absorbing into either your tile or grout.

Reseal approximately every two years.

When done, please take time to share your handiwork.

Hope this helps!

Pat InPaint

Posted 2016-04-06T20:51:43+0000  by Pat_HD_ATL


Thanks for joining us here on the community.

Any professional tile installer will recommend you to NEVER apply any pre-mixed tile mastic/adhesive/thin-set mortar over drywall....even with an oil-based primer placed first on the wall.

The amount of water in the adhesive in time can penetrate into the drywall. It may not happen quickly, but over time the moisture can be trapped behind the tiles, allowing failure and making even more of a project than was expected. It's a risk that I never want to see any customer make if it can be avoided.

This is especially true for older drywall where the paper facing is fragile. So at the end of the day, is it possible to install tile via mastic over sheetrock? 

Absolutely. But is the best choice? Never.

Personally, I would go for another direction to ensure you never have to repair all the hard work you've already done.

The good news is for your situation is that you don't have to replace the drywall with tile backerboard or even use tile adhesive!

How you may ask?

It actually all starts with using a tile setting mat, the SimpleMat. It works as a double-sided sheet of epoxy glue that will fasten to the wall, and the tiles will then go over it.

Custom Building Products SimpleMat 10 sq. ft. Tile Setting Mat

I recommend this because I've not only sold a great deal of SimpleMat, but I've personally used it as well. 

It's just like its name; it's easy and fast to use versus any pre-mixed or powdered tile adhesives. Once SimpleMat is set properly and you place tiles over it, you are guaranteed a sturdy installation. 

In fact, the glue used on it is just as strong, if not stronger, than most mastics and tile adhesives rated for vertical surfaces.

Since there is no drying time on them, simply press the tiles onto the sheets are ready to grout if you like!

Since SimpleMat is paper thin, the only thickness you'll incur on the tile install will be the tile itself. However the SimpleMat isn't paper; it's a plastic backing that can and will block out moisture from the future grout and any water that will be splashed on it.

If installed properly, it will be a water impermeable barrier between the drywall and tiles. No primer will do this, no matter the recommendation given. 

This makes it really your best option for installing tiles on your powder bath.

It is sold at your local Home Depot's tile aisle and comes in at a great price, so it saves you time and money for installation costs.

Once you install your tiles over SimpleMat, you can then grout and seal the tiles as you wish. And yes, simply come down to your local Home Depot and pick out the best non-sanded grout you like that will compliment your tiles.

View the links for SimpleMat in orange above for additional information. Remember that once you use this, absolutely no need for tile adhesives will be necessary. Just ensure the drywall is clean and level before installation, but no primer coat is required.

The only final thing to finish the tile installation would be to seal the edges via caulking. Opt for a silicone-based version that will provide years of flexibility and strength so no water will seep through and damage the drywall underneath.

Let us know if you have any additional information.


Posted 2016-04-06T21:47:02+0000  by Joseph_HD_ATL
Not what you were looking for ? Try posting a question