Primer under Tile??

[dicko]

I'm redoing the bathroom which had 4 inch tile around the bathtub. I managed to get them all off without seriously damaging the walls, which are plaster. All the walls have had the paint removed down to bare plaster.

My question is: do I prime the walls under the new tiles or do I leave the wall bare where the new tile will go. Googling around didnt really turn up anything definitive on the subject. The answers seemed to fall in three categories

1. Yes
2. No
3. What does the tile manufacturer say?

I havent bought the new tile yet so I cant ask the manufacturer so I'm asking here.

-dickm

[EXT]

It will all depend on how thorough you want to be in redoing that bathroom. With plaster walls, much will depend on whether there is a shower in the bathtub. If there is, it is amazing that it held out so far. You really should install a water proof membrane such as the Schluter system or equivalent. Then you should follow their directions. If there is not a shower, then follow the directions on the adhesive or thin set mortar that you plan on using. I am going for a "yes" on an oil base primer before installation, with plenty of time for the primer to dry.

[David Nebenzahl]

On 1/17/2009 5:16 PM EXT spake thus:

I assume you're talking about Schluter's membranes like Chloraloy, Kerdi, etc., right? Great stuff if you're building a shower pan from scratch or waterproofing an outdoor masonry deck, but wouldn't that be overkill for retiling a tub enclosure?

I've got to assume that the OP's tub has a shower, as every tiled tub enclosure I've ever seen has one.

My understanding is that in situations like this it's enough to use the "green" drywall under the tile if re-sheeting the walls. In the case of plaster walls, however, do you really need to do anything? I ask because every tub enclosure I've seen in old houses with plaster walls (pre-drywall) has been in pretty damn good shape.

In any case, I don't think that primer is going to do you any good here. No way it can form any kind of water-resistant barrier.

I'm curious what others have to say about this here.

[dicko]

Here're are more details.

First, there is a shower but there is no no shower curtain or tub enclosure so the shower is pretty well useless. The house was built in 1957 and I doubt anyone ever used the shower. The tiles only went about 2 ft up from the tub, the rest of the wall is plaster so its survived for 50 years.

The reason why I'm doing the remodel is that the paint is peeling from the walls. This is happening in the whole house not just the bathroom. Its like the primer under the paint just turned to powder and the paint is separating from the plaster. I just took a razorblade and scraped all the paint off with no damage to the walls. However, where there was primer under the tiles, it was stuck tight. The razor blade couldnt scrape it off. About he tiles themselves, about half fell off the minute I touched them. The adhesive had dried out.

So now I'm down to bare walls, and I'm just wondering if primer will interfere with putting new tiles back on the wall. Judging from where there was primer under some of the old tiles, I'd say no.

-dickm

[gpsman]

Mastic will stick to practically any clean dry surface. -----

- gpsman

[cshenk]

"dicko" wrote

Thanks. This clarifys it.

I have plaster walls too in the bathroom. Had tile and it rotted out eventually. Now I have a tub enclosure.

Lovely ;-)

Opinion here from what you say is that it cant hurt. You'd also want to make some sort of backer board to protect the plaster walls i imagine.