Tile over greenboard in shower?

I'm in the process of re-doing a small bathroom. I had planned on putting up a three piece tub surround, so I used greenboard coated with kilz around the tub and shower. After seeing some of the kits, I think tile would look a lot better. When I demoed it, the house was built 30 years ago with tile over greenboard, and it lasted a long time so it looks like it can be done if its done right. Looks like now you should install tile over backer board, but I'd rather not tear it down and re-do it if I can avoid it. The greenboard is sealed with kilz and im going to make sure it is tiled, grouted caulked and sealed properly. Budget is definitely a factor. What should I do?

You should do it.

(Being serious)

ETA: Just look up some DIY shower wall tile videos. You sound like a hands on enough guy, so Im sure you'll figure it out.

Is the flanged tub already installed?

yes, the tub was already there. I tore down all the drywall because when I recently retiled the floor, I had to replace some rotted areas around the tub and toilet. When tiles started to pop off I thought there would be a lot of damage behind the tob so I ripped it all out to see what was going on. Water was collecting in the 1/4" gap between the tub and the drywall and making its way around the permieter of the tub and making its way down to the floor. The rotted subfloor has been torn up and replaced.

Just so I'm clear, The orginal tub is still in place and new drywall has been installed and finished down to the flange?

Tiling over greenboard is far from ideal and I don't recommend it. Having said that, there is plenty of tile around that was installed on top of greenboard. I would recommend that IF you do install tile on the greenboard, you need to coat it with something like Redguard or similar. I still recommend removing the greenboard and using concrete tile backer board. I would still coat the concrete backerboard with the Redguard. I did install tile over greenboard in my current house with Redguard under the tile (didn't know any better at the time) and it's still nice and dry and watertight. I would not do it again though. Next shower that I tile will probably have concrete backer board.

I have not personally used it but Schluter products makes a foam backer board for tile that is supposed to be great. I have used Schluter's Ditra and love it so I suspect that their wall systems are good too. Schluter products can be hard to find where I live so you might have that problem as well.

there is a 0.25" gap between the edge of the tub and the bottom of the drywall, over the lip

id say removing it isnt really an option. IF it was absolutely necessary, could I put 0.25" hardiboard over the existing sealed drywall?

Since you don't want to remove it, I would coat it with Redguard or its equivalent. Pay special attention to the area where the board meets the tub.

I still don't recommend it and in some areas, you might be violating some code by doing so...depending on what codes are in your area. However, I think it will work fine.

I would just put a layer of Kerdi over the drywall and tile over that. I'm not a huge proponent of cement board products. I think they are often used incorrectly.

Not in any place a shower gets used much.

Not correct.

The tile industry has never supported thr use of green-board in wet areas.

It fails.

Every time.

While tile is often capable of stopping all water, all those grout joints are not and water gets behind the tile.

Just use the correct cement board and do it correctly.

Dumb statement. What isn't going to fail eventually?
I have also seen many older showers with tile on green board.

I have seen quite a few showers that the tile was installed on greenboard years ago and when they are torn out, they are still dry. I've even seen tile installed on regular drywall with no issues.

Yes there certainly are potential issues and using drywall of any type under tile certainly isn't the best way. However, it will work especially if you use something extra to waterproof the board such as Redgard or Kerdi.

In summary, tiling over green board is not preferred. Can some applications make it to the next update? Yes. With a non porous tile, and epoxy grout, chances increase. Use a waterproofing membrane, your odds are even better.

I would highly recommend a membrane no matter what you do. Kerdi is my preference.

I assume it isn't the cost setback deterring you from cement board, it's the time investment. With materials on hand, you should be able to tear out the drywall, install cement board, and install the Kerdi membrane in a short day. The Kerdi would be the most expensive part.

The weight of the tile combined with moisture will pull the facing off the greenboard and you'll have a huge crashing mess on your hands...not to mention a hell of a lot of mold.

Head to the store and get yourself a Schluter Kerdi kit and follow the install instructions. Problem solved.

That's why I like the Redgard. Quicker than Kerdi and works great. It's also cheaper than Kerdi. Kerdi is a great product though.

I don't know, if you use a fast setting thinset, you can start setting tile almost immediately.

I helped my stepdad re-do a bathroom in their old house with basically this same setup. We tore out the drywall, laid down plastic sheeting, then cement board, then the membrane and tile. I don't recall exactly which we used, but after a couple years, we opened up the other side of the wall to do some other work, and everything was perfect.

Alright...so we're back to the original idea of using the plastic tub surround. I don't want to put anymore time or money into this. Any tips for putting those up? They seem pretty easy. This will go over the kilz-ed greenboard.

I'm getting ready to redo my shower, and I've read online that if you're putting a membrane over your wall board, that you shouldn't use plastic sheeting behind it, as the two vapor barriers can trap moisture between them, potentially leading to problems. I don't know if that's accurate, though.

Oh, and this is definitely a tag. Some great info here. I'd seen the Kerdi kit installed on an episode of Ask This Old House, but I didn't know what it was called. Thought it was really slick. Although the Redgard looks like a good, cheaper alternative.

Just a follow up... we went to lowes and picked out a $59 5 piece tub surround. It was so flimsy it wouldn't even stand up if you placed it next to a wall. it was probably as thick as 3 sheets of paper. It was a pain in the ass to get everything lined up, and the corners ended up with gaps along the seams no matter what I did. Maybe the drywall behind it wasn't square, but who knows. It's up and I think it'll look ok once I hit the seams with some white caulk.

Im somewhat new here and dont post much,But I do know a little something about this.
My thought is this,The green board will be fine and work out for you if you do the job properly,ie no way for the water to work in behind etc.
The method I would do in my own home would be paper and lath,mud or float the wall then set tile.Even though I feel this would be the best way to set tile,just like greenboard you have to do it right and if not done properly you can get water damage.
Finale word for what its worth.I know and used to work with a tile setter from Germany that was 3rd or 4th generation marble mason who also won several nation wide tile competitions here in the U.S. and in Germany,he used greenboard as a way to cut cost for the customers and as far as I know didnt have any issues.
He hired me to do some marble slab work in showers and I set per his prep work and greenboard was used.The house is well known in this area I live and the work was done 11 years ago,if it had to be redone I would have heard about it as the granite world around here in this city is small.

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