Can You Put New Caulking Over Old Caulking?

Reasons to Remove Old Caulk

• Caulk creates the barrier that prevents moisture from seeping to the wall and creating hidden layers of mold and mildew, which means that the caulk itself absorbs a lot of moisture and therefore gradually builds up mold and mildew itself. Even if the infestation is not yet visible, the fact is that the caulk has absorbed moisture and can attract mold. If you simply cover up the old caulk with new caulk, you are trapping that moisture so that it cannot escape and creating an even better breeding ground for mold and mildew. Therefore, you must completely remove the old caulk before adding new.

Removing Old Caulk

• Removing old caulk is made much easier if you take the time to make careful cuts along the perimeter of the caulk. Instead of simply trying to dig it all out piece by piece, take a utility knife or razor blade and slice along the barriers of the caulk where it meets the wall and tub, for example. Cut as deeply into the caulk as you can and as close to the other surface as possible. After you've cut along the perimeter, you can pull most of the caulk out in one long strip; you may need to use a putty knife or butter knife to help you pry away any areas that get stuck. Some companies even produce caulk softeners if you need an extra boost of help.

Cleaning

• Mix 6 oz of bleach into a gallon bucket, and dampen a rag or sponge in the mixture. Clean out the joint where the caulk used to be and where you will install the new caulk. The bleach will soften any remaining caulk, and you can simply scrape it away with a razor scraper or putty knife. The bleach will also kill any mold or mildew spores that have invaded the area. If the joint is too small for a rag or sponge, use an old toothbrush that you won't use again. Rinse the area with clean water. Dry the area completely before recaulking to prevent moisture from getting trapped.

Installing New Caulk

• Your new caulk should be a sealant specifically designed for use in kitchens and bathrooms so that you know it is completely waterproof. Squeeze a thin bead of caulk into the gap. While the caulk is still wet, dampen your pointer finger in soapy water and run it along the bead to flatten it out and force it all the way into the gap. Ensure your finger is completely damp before you touch the caulk; otherwise the sealant will stick to you instead of the gap. Allow the caulk to dry for at least two to three hours before using the bathroom.