Serving San Jose For Over 15 Years
(408) 516-9131 TO GET STARTED



Whether it’s used on windows, bathtubs, flooring, or elsewhere caulking is a standard in American homes. It is a great sealant after all. The problem is without re-caulking, old cauk tends to crack over time leading to water seeping into and around areas it shouldn’t. Excess moisture in turn creates an ideal breeding ground for mold. In this post we’ll cover the caulking + mold connection to see why mold seems to appear around cracked caulking and what you can do about it.

Caulking Can Trap Air & Water  Leading to Mold Growth

Caulking is a waterproof filler or sealant used to seal out moisture preventing it from entering into areas where it shouldn’t. It is commonly applied around homes in areas that are exposed to moisture or direct water as a way to protect surfaces that are not water proof. Typically it goes unspoken about until its color changes from white to beige and mold growth becomes visible on it’s surface. Checking caulking around tubs and windows is the easiest way to prevent mold growth in a home. It is a good idea to periodically check caulking along bathtubs and windows for cracks. If one is detected you may simply re-caulk the area to reseal it, making it waterproof again.

When caulking cracks and water & air seep into porous surfaces an ideal breeding ground for mold is created. Being vigilant in inspecting your homes caulking go do wonders for preventing mold and mildew growth from ever happening. Caulk is so cheap and easy to apply that you can cut out and remove old cauking along with the mold and mildew attached to it and replace the caulking without ever hiring a professional.

What do you do when you discover mold or mildew on caulking? Simple, clean and re-caulk the area to prevent future growth!

How to apply caulk to bath tubs and window sills. A step by step:

Step 1: Caulk Removal

Use a scraping tool to remove old cracked, damaged, or mold infested caulk. Remember to be gentle during this process. You don’t to damage window sills or bath tub surfaces. You only want to remove the silicone caulk. Water based caulk will crack and break apart as you begin to scrape it. If the caulk is in fact silicone based it will feel elastic or rubbery and stretch.

Step 2: Clean, Clean, Clean

Next you’re going to want to take some care to clean the the surface underneath the caulking to rid it of mold and mildew. Be sure to be thorough, and use a vacuum or suction device to remove excess debris. It only takes a very small amount of uncleaned area to spur mold growth again. If you want to take the natural approach, vinegar or mineral spirits are great cleaners to use on nearly any surface.

Step 3: Dry, Dry, Dry!

Mold LOVES water in fact it literally lives on it. Did you know that mold can sustain itself & multiply with water alone! If you do not thoroughly dry the area before the next step you may be doing this process all over again in a few months time.

Step 4: Prepare The Area

Next you are going to prepare the area for caulking by lying down masking or painters tape around the the edges where the caulking will be applied. Be sure to take  your time, create neat lines, and use caution to tape off ALL areas that should not come into contact with the caulk once applied.

Step 5: Set It Up

To prepare the caulk for use follow the directions on the tube of caulk you purchased (available on, at Lowes, or Home Depot).

Step 6: Lay It Down

Load your caulk tube into your caulk gun and get ready to lay it down. Caulk should be applied in a steady, constant stream along the seam of the window or tub you are working on. Don’t forget that practice makes perfect. You can practice lying down the caulk in a steady stream by usizing an old cardboard box for a few practice runs before you go for the real thing.

Step 7: Let It Dry

Once you have allowed the caulk to dry (typically 24 hours just to be safe) you can remove the tape you used to outline the area.

Congratulations you’re finished!

If your home is suffering from mold growth that cannot be easily remedied by the process outlined above, please reach out to us here at H&L Restoration and Mold Remediation in San Jose for help. We are standing by ready to answer any questions you may have. The call is free and so is the initial inspection!