Paint New Drywall Before Tiling?

[Josh]

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 prep.

[hrhofmann]

I would certainly tape and level the joints so there is a flat backing for the tile and so there is a continuous backing to prevent any cracking of the tiles or grouting.

[EXT]

I always cover the drywall after taping and muding with a couple of coats of latex primer before tiling.

[Red Green]

"EXT" wrote in news:4ad13852$0$65854$ [e-mail]:

Pure speculation:

Drywall would suck up the moisture from the tile adhesive causing it to dry improperly and possibly weaken the bond. May depend on type of adhesive.

[Josh]

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 tiles.

[Red Green]

Josh wrote in news:860e32fb-d7a5-4846-8390- [e-mail]:

Shake/stir it WELL.

Putting up a separate topic shortly on this.

[dadiOH]

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 the sheet.

[RicodJour]

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.

R

[Red Green]

RicodJour wrote in news: [e-mail]:

Oh, the old RTFM huh?!

[Phisherman]

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.

[benick]

FWIW , in all new construction the drywall is finished and primed before cabinets , counter top and back splash...Never heard of any problems....

[Dan]

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 applied.

[hrhofmann]

The OP was 5+ years ago!!!!

[Alz]

replying to hrhofmann, Alz wrote: I have this question today, so it doesn't bother me that the thread is old!

[Alz]

replying to hrhofmann, Alz wrote: I have this question today, so it doesn't bother me that the thread is old!