Replacing damaged tile surrounding tub/shower

Q.    The 4-inch square tiles on the back wall of my tub/shower in my 65-year-old house are about to fall off the plaster and lath wall, which you have probably guessed is also in bad shape.

Damaged tile
Tile starting to fall off

Which way should I go to repair this problem? Tear everything out to the studs, install plaster board or plywood (which kind?), apply a sealer (which kind?), and re-tile? Or should I go back to the original way–clean the area down to the lath, re-plaster (base and top coats), apply a sealer and re-tile? Sincere thanks for your help.

A.    The best way to go would be to remove everything to the studs and start over by applying backer board to them. Then install the tiles after cleaning them up or buying new tiles.

If this is an exterior wall, make sure that the insulation is in good shape, staple a 6-mil plastic vapor retarder to the studs, and fasten the backer board to them.

Recommended caulk for use in bathrooms

Q.  I would like your recommendation for a caulk for bathroom applications: shower enclosures, sinks, base of the toilet, etc. A few years ago, I used Phenoseal, because that is what a plumber used. I had previously used silicone caulk and found it difficult to apply cleanly.

The advantage of Phenoseal is that you can smooth it out with a damp finger (or similar shaped rod) to get a clean bead. If you make too much of a mess, you can clean it up with a wet sponge and start over. You can’t do that with silicone.

Now the downside: After a year or so, a slight amount of black mold started growing in the caulk, mainly in the shower enclosure (not surprising since it’s a wet environment). Note that I had bleached the area before applying the caulk, and I tried bleaching it when the mold first appeared. This helped some, but now 5 yrs later, the caulk in the shower enclosure is heavily overgrown with mold, and I need to replace it.

Should I still use Phenoseal, perhaps with an anti-mold additive? I assume that Phenoseal is susceptible to mold because it is a water-based (latex?) compound. Or should I switch back to a silicone caulk and practice, practice, practice laying down a clean bead?

A.    In my experience, silicone is the worst thing to use at the joint of a tub and tiles. I have seen so many failures in my nearly 60 years in the residential construction field. It will eventually peel and allow water to get behind it, leading to serious problems.

I have used polyurethane caulking for bathrooms for many years. But you need to allow the caulking seven days air-curing before you can get it wet or it will turn yellowish-pink. Even then, the white caulk will turn slightly greyer over time.

You can find polyurethane caulking in building supply houses that specialize in masonry and waterproofing products. A.H. Harris, with stores throughout the east coast, carries Sikaflex 1-a, my favorite and a product I have used for 50 plus years. Their website is

You may want to try Dap Kwik Seal Plus Premium Kitchen & Bath Adhesive Caulk with Microban. The manufacturer says that Microban fights mold and mildew and the growth of stains and odor-causing bacteria. Although it is a siliconized latex caulk, it has much better adhesion than pure silicone caulking. It is guaranteed crack-proof.

Unfortunately, although the caulk remained white, I have also experienced separation between tub and tiled walls in year-long tests on the same tub, half of which was caulked with it and half with Sikaflex-1a.

Re-surfacing a bathtub

Q.    The surface glazing of my bathtub is mostly gone. I do not want to replace the tub at this time and would like to refinish it until such time as we remodel the bathroom. Apparently, there are several different professional refinishing systems available (acrylic, 2-parts epoxy, etc.) Which system is best in terms of durability, resistance to discoloration and chipping, etc?

A.    Bath Fitter installs acrylic tub and wall liners directly over your existing tub — and walls if you choose the entire package. They claim a very long life expectancy of 25 to 30 years. Perma-Glaze is a different process that is applied over chips or the entire surface of tubs and sinks. Of the two, my personal feeling is that the acrylic liners may be more durable.

Be aware that neither of these systems will give you as hard a glaze as the original, so do not use harsh cleaning compounds on it.

Cleaning glass shower doors

Q.    Can you please advise of how to properly clean glass shower doors? I use a squeegee after each shower but spots seem to never be removed? Any suggested approach or cleaning solutions/tricks of the trade?

A.    A reader e-mailed me that she has very successfully used Mr. Clean Magic Eraser for shower doors as well as other bathroom surfaces. I haven’t tried the product myself, but intend to do so. Let me know if it works for you, as the best evidence I can get is testimonials from readers.

Refinishing an old bathtub

Q.    We recently remodeled our circa 1942 bathroom. We replaced everything, but decided to keep our white, cast iron tub (we have a separate shower stall). The tub is in good condition, aside from some water drip marks and rust around the drain.

Our plan was to have the tub reglazed, but I have heard differing reports on the effectiveness of this. We have 4- and 5-year- old sons, who bathe frequently, so durability is a big issue. Can you give us some feedback on reglazing or offer some other solutions? Thanks.

A.    What lucky parents you are! Young sons who bathe frequently! No hassles, no fights?

Tubs can be successfully reglazed but the reglazing is nowhere as durable as the original finish so no harsh cleaners can be used. Another option is to have a new acrylic tub liner installed. It is also not as tough as the original finish but it is likely to be tougher than the reglazing. Again no harsh cleaners.
You can find someone to reglaze your tub in your Yellow Pages under “Bathtubs & Sinks-Repairing & Refinishing” and someone to line your tub under “Bathroom Remodeling.”

Advice on bathroom remodeling

Q.  We have two and half bathrooms. The two are upstairs where one is in the master and the other is a hall bathroom shared by the other three bedrooms. Both bathrooms currently have bathtubs with showers and curtains.

We are empty nesters in our late 60s and we are planning on remodeling both upstairs bathrooms. My wife and I are discussing changing one of the tubs/showers into a walk-in shower but we cannot decide which bathroom to put the walk in shower in. There is more room in the hall bath, but the Master bath seems to be a more logical place to put the shower.

We’re interested in your opinion which bathroom would be best to locate the walk-in shower. Thank you.

A.    I vote for the master bathroom, as it is the one most favored by prospective buyers since most people take showers. Anyone who wants to soak can use the other bathroom.

You can get shower units that are 5-feet wide – same size as tubs – and they are great; you don’t feel crowded in them. Some have useable seats and others are plain.

Good luck with the remodeling.

Copper pipes turning green

Q.    The copper pipes in my bathrooms have oxidized and the white tiles, grout and bath mat have turned green. There are also green deposits around my faucets. I am getting ready to redo my master bath and am wondering what kind of pipe I could use instead of copper to avoid this.

I’ve been told that the pipes oxidize because of low pH in the water. Our town has hard water and I have purchased a water softener, and I also have filters at the water main. Any suggestions or insights for me?

A.    You should address the pH of the water instead of switching to plastic pipes. The low pH is eating up all your pipes and you may eventually face a very expensive replacement as well as repairs to areas that may become damaged by leaks.

Have a water specialist analyze your water and recommend what needs to be done to bring the pH to a neutral 7.

Bathtub Caulk

Q.  What is the best brand of caulk to use around a shower or bathtub?

A.    There are two issues to consider. A bathroom caulk that is mildew-resistant and one that I consider the best. Here is a repeat of an answer to another reader last April:

Some time ago, I tried  DAP KWIK SEAL PLUS Premium Kitchen & Bath Adhesive Caulk with Microban because of its claim that it is mildew-proof. I caulked half of our tub with it and the other half with Sikaflex-1a polyurethane caulking/sealant, which I have used for over 50 years in all types of construction applications.

I decided to give DAP’s product a try because some of my readers had reported that Sikaflex-1a had turned pink after a while, or simply did not remain as white as when first applied, which does happen if Sikaflex-1a is not allowed to air-cure without being repeatedly wet for a week (hard to do if your tub or shower is the only one in the house).

Although the DAP caulk remained sparkling white and did not mildew, I found out that it began to peel off the wall in about a year, typical of siliconized products, whereas Sikaflex-1a was still firmly stuck to both the tub and the wall. Sikaflex-1a tubes sell for around $5 in A.H. Harris stores ( found throughout the Northeast. You can also buy it from DHC Supplies, Home Depot stores do not carry Sikaflex-1a, but Sika Construction Sealant, which looks quite the same to me.

Sikaflex-1a has not mildewed in my experience, but that does not mean that it won’t under different conditions. Which one to use is a personal choice. For me, after the “test”, the choice is Sikaflex-1a every time.