Before applying new caulk around your bathtub, shower, or sink, you must firsts remove the old caulk. New caulk doesn't stick to old caulk, so if you fail to remove the old stuff, the new caulk can't form a watertight seal, leaving the potential for moisture to seep into areas where you don't want it.
The best way to remove caulk is through a combination of chemical caulk remover and manual tools. Chemical removers require some time to soften the caulk, so if you are in a hurry or don't want to use chemicals, you can also remove the caulk with hand tools alone.
One easy way to start the process of caulk removal is to use a caulk removal solution, such as the products made by 3M, DAP, and other brands. This chemical remover destroys the bond between the old caulk and the tile, tub, or sink, making it very easy to pry out of cracks and crevices.
A small bottle of liquid caulk remover costs $10 to $20 and will remove about 20 linear feet of caulk—enough for most bathtubs. Follow the manufacturer's instructions for use.
Equipment / Tools
- Plastic putty knife
- Caulk removal tool or razor scraper
- Chemical caulk remover
- Rubbing alcohol
Apply Chemical Caulk Remover
Squeeze chemical remover onto the old caulk bead so it is covered completely.
Allow Caulk to Soften
Let the caulk remover sit on the caulk as directed by the manufacturer's instructions. Some users report that it helps to allow the product to set overnight for maximum effectiveness.
Scrape Away Caulk
Use a plastic putty knife or other tools to scrape away the old caulk. If possible, try to peel it off in strips as you scrape.
Inspect the area thoroughly, and remove any remaining caulk residue with the tool. A caulk removal tool or razor scraper (see below) can be useful at this point.
Clean the surfaces thoroughly with a clean cloth moistened with rubbing alcohol. Let the surfaces dry completely before applying new caulk.
Using a Caulk Removal Tool
Several manufacturers make caulk removal tools, which sometimes come in kits that include tools for applying and smoothing new caulk. The better tools are made of plastic or polished steel that won't scratch surfaces and have angles and blades designed to scrape caulk out of narrow crevices and corners. One excellent tool from Hyde has a corner scraper blade that is reversible and replaceable to ensure you always have a sharp tool.
Caulk removal tools can be used by themselves, but they are also great as the second step after applying chemical caulk remover.
After scraping out the old caulk, inspect the joint to ensure you've removed it completely. Before applying new caulk, clean the surfaces thoroughly with a clean cloth moistened with rubbing alcohol, and let the surfaces dry.
Using a Razor Scraper
Another tool that works well is a good, old-fashioned razor scraper. The trick here is to use a very sharp blade and to make sure the blade edge is flat on the surface to prevent scratching. A razor is ideal for getting behind thin smears of old caulk.
In general, it is best to scrape behind both side edges of the caulk bead to separate it from the surface, then try to peel it off in long strips. To prevent scratching, be careful not to let the corners of the blade contact the surface. Keep the tool at a low angle—almost flat to the surface—at all times. Acrylic and fiberglass surfaces are especially susceptible to scratching.