Do It Yourself: Cracked caulk should be removed and replaced

SUNDAY, AUG. 7, 2011

Q. My house has two older bathtubs, both of them caulked at the joint of the tub and the tile wall. The caulk is cracked in places, black with mildew and dirt in other places. How do I remove this old caulk and how do I get a lasting re-caulking job?

A. Removing the old caulk will take some scraping. Jab the caulk in several places with the point of a utility knife. If the caulk seems hard and brittle, it probably has a water or oil base. If the knife point sinks in rather easily, the caulk is probably silicone, which forms a softer, rubbery strip.

My favorite tool for removing old caulk is called a Five-in One tool. It is about the size of a putty knife, but with a wider, sharper blade. The blade has a sharp hook on one side that can be used to pull out chunks of caulk. A razor blade scraper can also be used.

When scraping, use extreme care to avoid scratching the tub or tiles. If the caulk appears to be silicone, work a corner of the tool under it, grasp the loose end and pull.

Silicone can sometimes be pulled off in strips. Even if most of the caulk comes off cleanly, you will still have to scrape up some remnants.

If the caulk is hard, you will need to soften it before scraping. You can try a solvent like 3M Caulk Remover, sold at home centers and on the Internet. You can also use a heat gun or gun-type hair dryer; be sure the tub is dry and use a moderate heat setting, especially on acrylic or fiberglass tubs.

When you get the old caulk out cleanly, scrub the area with denatured alcohol to remove soap scum.

Many brands of tub caulks are available, some claiming special resistance to mildew. I think silicone has the best resistance to water, but can be more difficult to smooth and clean up than a water-based acrylic.

Some do-it-yourselfers put a strip of masking tape around the tiles, about 1/4 inch above the tub rim, and another strip around the rim itself, forming a space to be filled by the new caulk. When the tape is pulled off, it leaves neat, straight edges on the caulk.

Another trick is to fill the tub with water before caulking. This helps prevent the tub from pulling away from the new caulk when it is used.

Some bathtub caulks are available in toothpaste-type tubes as well as larger caulking-gun cartridges; the small tubes are easier to use in the confined tub or shower and, if there is only one tub to caulk, there is less leftover caulk to deal with.

Finally, some experts recommend pushing the tube of caulk instead of pulling it, to force the caulk deeper into the joint.

Whatever you do, give the caulk plenty of time to dry before using the tub or shower, and read the directions and cautions on your caulk before starting.

Q. How do I remove ivy from a stucco chimney without wrecking the stucco?

A. You’ll need a sharp lopper (the long-handled tool used to prune moderate-sized branches from trees), a smaller, hand-held pruning tool and possibly a pry bar.

Start by lopping off the ivy just above the ground. When the leaves start dying and access is easier, use the pruning tools to cut the ivy loose from the chimney. You might have to carefully pry some of it loose in order to get access to the tendrils attaching the ivy to the stucco. Cut the ivy from all the tendrils.

Next, kill the tendrils. Some experts recommend brushing them briskly with a steel-bristled brush. I recommend a brass-bristled brush instead, since steel can leave small particles that can rust and cause stains.

Another strategy, which requires great care to avoid starting a fire, is to burn off the tendrils with a propane torch (never use a torch near or on wood or other flammable materials).

There will probably be some minor damage to the stucco; you can patch small chips or cracks with Quikrete Stucco Repair. This is an acrylic product that contains sand to match the texture of stucco (visit www.quikrete.com for more information).

Repairs will have to be touched up with an acrylic paint that matches the stucco.

Questions and comments should be emailed to Gene Austin at gaus@17aol.com. Send regular mail to 1730 Blue Bell Pike, Blue Bell, PA 19422.

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