Recaulk Tub Now Or Forever Scrub Your Mildew Stains

Q: I am writing about mildew buildup along the caulking rim around my tub. It has penetrated the caulking and is black. I have tried bleach and many over-the-counter sprays, with no success. Others have suggested having a plumber recaulk it, but I did that once and it gets expensive.

A: First, some basic facts about mildew. Most important, mildew must have moisture to grow. Mildew spores are literally everywhere in the air and will take any convenient opportunity to move in. But, like Dracula, mildew must be invited in. The most common way people do this is by leaving the shower and tub dripping after use, and by having inadequate ventilation in the bathroom.

Mildew is capable of permeating tile grout, wood, caulking compound, porous concrete and stone, drywall and paint, and can grow on anything that stays damp including plastic, porcelain, glass and metal.

Once mildew has penetrated tub caulking, it is virtually impossible to get out. Mildewed caulking must be removed.

A common error many people make is to cover the mildewed caulk with a new coating of caulk, at which point the mildew eats its way through the new caulk and it looks as bad as before.

In your case, you don't need a plumber to recaulk the tub rim. You could hire a less expensive handyperson, or you could tackle this one yourself.

Using a small razor-scraper and a putty knife, remove all the old caulk. Sometimes, if you have white tile and a white tub, it can be a little tricky to make sure it's all removed.

Once the old caulk is completely removed, you will need to scrub the area thoroughly with a bleach-based cleanser and a stiff brush. It's a good idea to leave the damp cleanser on the area for a few hours or overnight so it can thoroughly penetrate the seam between the tub and the tile.

Then rinse off the area, wipe dry, and allow to dry completely, possibly with the help of a fan or blow dryer. Now you are ready to recaulk.

The seam between the tub and tile is caulked with a flexible sealer because tubs expand and contract when filled with water, and regular tile grout will crack and separate over time.

Before applying the new caulk, fill the tub with water, which will simulate those times when the tub is moved as far away from the tile as it would be during normal use. Make sure the seam doesn't get wet again while filling the tub.

Use the smallest amount of caulk to just fill the gap between the tub and the bottom of the tile, pressing the caulk into the seam and smoothing it with your fingertip or a rag wrapped around your fingertip. Wipe off any excess caulk that might have gotten smooshed onto the tub or tile.

Read and follow the instructions on the caulk to clean up the area, then protect the new caulk from moisture until it is "cured," an amount of time that will also be listed on the label.

Mr. HandyPerson is rather biased toward your doing this project yourself. Why? Because once you have gone through the tedious and messy process of removing the old caulk, scrubbed the area, waited for things to dry thoroughly and recaulked the tub yourself, he thinks you will be more motivated to do what you must do to keep the mildew from coming back, which is: Get an inexpensive, nonrusting squeegee and a soft cloth towel, and use them to squeegee the shower walls and wipe off the plumbing fixtures after every shower for the rest of your life. With a little practice, this should take a half minute or less after a shower or bath, and it will truly prevent mildew from ever again rearing its ugly head in your bathroom.

(Copyright, 1996, Universal Press Syndicate)

Mark Hetts' home repair column runs as space allows in the Home/Real Estate section. Send questions and comments to: Mr. Handyperson, P.O. Box 70, Seattle, WA 98111.