Re-caulking a tub

I would like to change the caulking around my bathtub. How can I remove the old caulking, and what’s the best method to reapply it? I’ve tried it before, but it always ends up looking bad. What am I doing wrong? - Denis Ouellette, Glaslyn, Sask.

Recaulking a tub is a straightforward maintenance project, but it can be tricky. To remove the old caulking, there are a few commercially available products that can help, but in my experience, you can remove the old caulking quite effectively with a single-edge razor blade. Put a drop cloth in the tub to protect it. Also, run a strip of masking tape around the tub, just outside the caulking, to protect the adjacent surfaces. Hold the razor blade as parallel to the horizontal edge of the tub and the vertical wall of the surround as you can manage, and score the caulking. Join the two cuts so that you can remove the bulk of the caulking. Then, working ever so carefully, use the razor blade to shave off the remaining caulking. If you are worried about scratching, try plastic razor blades available from Lee Valley Tools. Then give the area a good scrubbing with mineral spirits.

When the area is thoroughly dry, it’s time to reapply the caulking. Make a conservative cut in the tip of the caulking tube to limit the amount of caulking that comes squirting out. The hole on the end doesn’t need to be much more than 1⁄8" in diameter. Apply the caulk at a steady pace and then, using your finger, smooth it into a nice quarter-round fillet. There are tools for this purpose, but every pro I’ve ever seen uses a finger lubricated by a quick lick. Having a container of water and a rag nearby is a good idea. Don’t smooth the caulking more than once if you can help it. If you touch if after it begins to skin over, you’ll make a mess. If you make a mistake, quickly wipe up the mess and start all over again, making sure that no caulking residue is left before you try again. If freehand caulking isn’t working, try masking the area to be caulked, just as you might if you were painting.

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Michel Roy is a residential contractor