primer for humid bathroom? tile over top?

MacDoe

Hello, can I put ceramic tile over a primered drywall surface or will it interfere with the thin set adherance. I feel the need to at least primer the sections that have been covered with drywall mud. What is correct? What is a good primer, I have already purchased BEHR Premium plus enamel under coater primer and sealer multi purpose stain blocking formula 100% acrylic latex adheres to glossy surfaces. Is this o.k to use have not opened yet? Thank You.

George Z

That primer will be fine.
Very sticky to work with and sold by the devil, but it will do.

ProWallGuy

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MacDoe

O.K not sure what that means, who is the devil?

George Z

The "devil" is a metaphor for the retailer you bought the paint from.
To most of us, they are the competition and one of their purposes seems to be, to put us out of business.
Most professional painters that pass by here don't like using BEHR Paints.
Having said all that, what you have will work fine for your purpose.

Bud Cline

Where are these walls to be tiled? You should know that paint is a known bondbreaker for some tile installations. Are these walls ina wet area such as a tub surround or what?

MacDoe

Thank You for explaining, and for your reply to my post. Yes I plan to tile the entire tub surround and carry the tile half way up the wall behind the toilet and then the same for behind the sink. I have spent quite a bit more money than I originally anticipated on the tile thanks to the better (took her 5 months to decide on tile) half. I was only planning to prime the areas that have drywall mud compound where the tile will go and then prime and paint all other areas. I bought the primer only, as the selection on paint color by my calculation should be 5 years from now, all things considered there are many more shades of paint than different tile in our area. I want to make sure to do this properly as this is the first time I have done drywall or tile laying. I think I am into the fun part of this project as I have overcome the re-wire and replumbing portion, but as I have already learned from this not to be to confident,but, I wanted to first consult the experts. So should I prime before tile or just lay tile over top of drywall/mud bare as to not "break the bond" ?
Sorry for going with Behr, the Devil made me do it, do painters not like Behr for where it is sold or is there a quality issue? Thank You

Bud Cline

There may be a little confusion lurking just around the corner here.

In the dry areas primer would be OK but you can use mastic tile adhesive in those areas and you could just as easily skim-coat the drywall mud with the mastic before installing the tile. If you want to prime these areas that should be OK also as this is done all the time.

In the area of the tub surround this may be a different story. If there is a shower with this tub then the drywall shouldn't be there at all and nothing you do to prime the drywall mud will last for very long. This is with one exception. That exception would be to use a liquid waterproofing such as Redgard (sold at Home Depot) to waterproof the drywall mud. The thing is....this isn't the answer either and the drywall should be replaced with a suitable cement board tile backer.

So.....shower, or no shower?

billinak

I'm suprised no one else has mentioned that you CANNOT put tile on drywall, no matter which primer you use. You must first demo all the drywall and replace with cement backerboard, otherwise you're looking at a very temporary tile job that will just cost you money to replace when it all falls down around your ankles in another year or two.

dougrus

Not to be confrontational, but this is not true. You CAN put tile on drywall surfaces. In a wet area that gets direct exposure to water it is definetly a no no, but if it is a backsplash or other wall tile applications it is perfectly fine. Drywall that is painted is not a good surface because of the bonding issue. Of course its not quite as good as cementboard, but its done all the time.
Tubs and shower surrounds of course you must do CBU

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MacDoe

hi there I have cement backer board for the tub surround and water proof drywall for behind the sink and toilet where i will be tiling from the floor to about half the wall behind the toilet and sink. the tub surround am tiling all the way to roof but not tiling ceiling. So should I only primer where I am going to paint?

Bud Cline

MacDoe I'm not a painter but in this case I will say "yes" to your question: "primer only where you are going to paint."

The raw drywall would be better for the tile adhesion.

I will also clear up another point. You don't have "waterproof" drywall, you may have (MR) moisture resistant drywall. For future reference, even MR is not to be used in a wet area.

Bud Cline

I also meant to ask earlier: "Why is this bathroom humid?" Are you saying this simply because it is a bathroom?

joewho

Waterproof drywall...meaning "greenboard"?

I have to say, I did a job once where I ran the primer onto some greenboard and the tile installer wouldn't hang the tile on it.

I had to go back with a wallpaper perferator so his adhesive would soak into the drywall.

I'm not a tiler, but in construction I see them hang tile directly on to greenboard all the time. They prefer that over a primed surface.

Your configuration should be fine.

MacDoe

Thank you all again for your responses, and thank you to my better half for barging in on this post. I just got home from work and began to read the responses from MY last post #4. Then I got to post #11 , low and behold it had me MacDoe next to it. Guys, that is my girl at post # 11. She must have been checking the responses while I was at work and decided to clarify that I did not use just ordinary drywall in the bath/ shower surround. She did confuse things a bit , bless her little heart though she likes to be involved, maybe felt she should defend my efforts as soon as possible, I really don't know why she did this, she could be involved more by picking a paint color already. She saw my other post obviously and I got raked for making jokes at her expense, not really though, she laughed at herself as well. She's cool, anyways, I would like to clear this up as it is being beat to death. I did not use cement board in the tub surround, but rather a product called dens-sheild , it extends about a foot past the tub skirt then to the ceiling. I had a piece about 3' by 5' left over so I used it for the ceiling directly above the tub. I thought this would be added moisture protection from steam of a shower to have this on the ceiling but now that I am thinking, the surface of this dens sheild is very rough probably to grab the tile adhesive and I will have to think of a way to smooth this out. Does drywall mud absorb moisture? I put drywall mud all over the seams of this dens sheild in the tub surround as well as tying it into the green board outside the tub surround. I guess what I am asking for is an answer to this question: should I prime the drywall mud so that it will seal out moisture that may get behind the tile or did I go wrong by using drywall mud in the first place for this dens sheild. Maybe I should have used this red guard the home depot sells to smooth out the seams or maybe I should have used nothing at all but rather use the tile adhesive to fill the seams, I don't know, the more I think about this the more I think that I should not have used drywall mud in the tub surround. I spoke of the humid bathroom because bathrooms are humid right ,you nailed it.