I've installed new 1/2" conventional gypsum drywall in the area
between my kitchen countertop and the bottom of the wall cabinets.
I'm looking for some decorative ceramic tile to use as a backsplash
over/behind the sink and extend it around to the area over/behind the
range. What I'd like to know is this:
Once I find the tile I want to use on that wall, is it necessary to
prime and paint the new drywall before applying the tile mastic? I
haven't bothered to tape the joints yet; figure the 4x4 tiles will
cover the joints anyway. Just wondering if the mastic or thinset
mortar will adhere good enough to the bare drywall without any special
OK, thanks guys. It's not a very big area and I have a fresh, nearly-
full gallon of Kilz latex primer. I'll prime it before tiling. Still
don't see the value of taping the joints that will be tiled over,
though. They're all butt joints so no valleys to interfere with the
Doesn't anyone read the manufacturers instructions? All manufacturers
of tile mastic specifically mention drywall as a suitable substrate
with no mention of paint or primer.
Tape the joints so there will be no movement between the pieces of
drywall. The movement could pop tile.
I have a lot of Saltillo time...made 4" mop boards (base boards) of same.
They are all stuck to the drywall with thinset. Some are on paint, some on
bare drywall. None have ever loosened (14 years). If I had my choice, I
would have put all on bare drywall.
Primed & painted, bond is as good as the paint is to the drywall paper.
Unprimed and painted, bond is as good as the drywall paper is to the rest of
Before you do anything, carefully read the manufacturer instructions
on the tile mastic container. Be critical about the drywall seams.
Do visual/feel tests using a work light against the wall, lightly run
hands over the seams. Wipe down walls with a very slightly damp terry
towel to remove the dust. If instructions do not say "prime" don't
waste your time doing it--it might even make adhesion worse.
If your tiling a floor you most surely need a backer board which has been
screwed down every 6" and had all of the joints meshed and mudded or the grout
will crack within months or even weeks. The exception being a level concrete
floor. Drywall is perfect for applying wall tile and backsplash. Type 1 mastic
manufactorer Mapei recommends priming as it "dramatically enhances the cohesion
between the tile, adhesive, paper and gypsum board" and I think the reason for
this is because they sell the recommended primer. The same instructions go on
to say "surfaces should be free of all dust, grease, wax sealer, paint and
primer" if you can believe it. I tape the joints and maybe add a few screws
were needed on unpainted drywall because if you tile over a crack or uneven
surface or floating drywall, your asking for your grout to fall out down the
road. if the wall has been painted with a glossy paint I always rough it up
very good with a drywall rasp to give the wall some "tooth" for the adhesive.
The main reason tile falls off is exhesive moisture/steam in the room or the
installer put to much adhesive on and it dryed out before the tile could be
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