# mastic on drywall



## joecaption (Nov 30, 2011)

100% sure you really want to do that?
Going to be near impossible to clean.


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## Marcy McPike (Jul 5, 2013)

*Yup!*

I have done it before. Maybe I didn't describe my intentions well: the pebbles/stones will go ABOVE the granite backsplash, about 4" high, directly on the drywall and will serve no other purpose than a decoration. I will grout around the stones as well. My concern was more about whether or not the moisture from the mastic will penetrate the drywall and cause problems. Last time I did this application I really did not consider the moisture in the mastic damaging the drywall. Thus, my quandary. I did this in a spa in my last house. Over the 7 years I lived there I did't see any problems, but the spa was not used very often.


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## oh'mike (Sep 18, 2009)

Tiling over painted drywall is fine---simply scuff sand the paint,lightly before proceeding.

You will be okay with mastic if the border is in a dry area--I prefer thinset as it sets faster and bonds better--

-you might investigate using a modified grout to set the pebbles,using the color you wish to grout the finished work---Youtube 

has an excellent video showing that--(I lost the book mark,sorry) I have used that technique with stone mosaics with good success.


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## Marcy McPike (Jul 5, 2013)

*Thank you!*

I appreciate your input! I will go ahead with the mastic as planned. I will also check out the modified grout idea!


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## oh'mike (Sep 18, 2009)

That worked well with the picky little mosaics----


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## jeffnc (Apr 1, 2011)

Technically moisture will probably penetrate to the drywall through the paint, but it doesn't matter. Think of how much moisture penetrates the drywall when it's first installed - when joint compound is applied 3 times to bare drywall. Or think about how much moisture there is when paint is applied to bare drywall.


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## ToolSeeker (Sep 19, 2012)

You will no water in your drywall. First this is not like a shower it's a backsplash any water that hits it will be small amounts. Second that small amount of water will not go thru the tile then the mastic then the paint.


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