HELP! Loose ceramic tiles/tub wall

I'm very unexperienced in this, but feel I could take this repair on with someone's help! I have 4 loose 4x4 white tiles on the first row just above the tip of the fiberglass tub and under the faucet for the tub. They are full size tiles, there will be no cutting. I would like to either repair or replace before the wall behind gets ruined. I pulled off one tile and behind is the greenboard, then a coat of something white, almost like a plaster feeling substance, then are lines of tan which I assume are the adhesive for the tiles. Nothing behind seems to be damaged yet. I think we did not have the tub/tile line sealed well and the moisture got in at that point. How hard is this going to be for me to do? What about the grout on the good 2nd row of tiles that are not loose? Appreciate any advice. THANKS ALOT!

Yours is the classic symtom in a "sheetrock shower." The damage appears at the bottom of the plumbing wall and eventually works its way up higher. The next place will be the long wall down near the tub or up on the window sill if there is one.

You must remove more than the affected tiles. Take out the row above also. Replace the damaged sheetrock with cement backer board. Fix it so that the top row of tiles you replace will bridge the joint between the sheetrock above and the new backer board. Use thin set mortar as the adhesive. Sounds like originally they used mastic, which isn't as good.

When the rapair has been made, allow the whole shower to dry for three days and then seal everything (tile and grout) with a tile sealer. To prolong the life of the shower, dry it completely after each use. I know it's a bother, but the cost of having the whole thing redone will set you back seriously.

There is more useful info on our tile and marble page.
http://www.johnbridge.com/serv02.htm

John