Caulk Options for Mold Resistance

Caulk is one of the most common sealants used to seal crevices or seams in household and commercial spaces. Caulking adds to the overall durability of any surface, protecting it against moisture-seepage and gradual deposition of debris or grime. Caulking is particularly recommended among daily use surfaces and those found in highly-moist environments. Mold is essentially a fungus and it is known to grow upon caulked surfaces too. There are different types of caulks and each caulking option provides a different degree of mold resistance. Most contemporary caulks are variations of the two, types of caulks explained below:

1 - Acrylic Caulks

Acrylic caulk is generally regarded as the best, residential caulking option, particularly for sealing surfaces prone to repeated mold infestation. Typical areas recommended for acrylic caulking include bathroom surfaces like sinks, tubs and kitchen countertops.

Commonly-acknowledged Features

Acrylic caulk seems to combine the best of caulking features, i.e. it is highly resistant to mold, apart from being easy-to-handle. This makes it a favored sealant option for many homeowners.

Acrylic caulk is reputed to have appreciable substrate features. This means that it can adhere well to most household surfaces. Further, it offers a reasonably-good painting surface. This is critical since caulking lines often need to be regularly painted in areas that are susceptible to repeated mold growths.

Acrylic Caulk Variations

Acrylic caulk is available in 2, basic options: it either has a water-based formulation (Acrylic Latex Caulk) or it is slightly siliconized (Blended Acrylic Caulk). The siliconized variety is also called silicone blended acrylic caulk. It is very durable against moisture seepage and is highly recommended in areas wherein moisture penetration is a perennial issue. However, this caulk variety isn't common used in residential spaces and it shouldn’t be confused with the silicone variety of caulk explained below.

In comparison, the water-based acrylic caulk is easier-to-handle in terms of periodic painting. It is easier-to-clean and the mold spotting can be easily cleaned with some soap and water.

Recommended for DIY Household Application

Acrylic latex is also recommended for homeowners who aren’t familiar with caulking since it is non-toxic and has a small curing period during which excess caulk can be easily removed.

More Variety

Among caulks sold specifically for mold and mildew protection, acrylic caulks offer the largest range of products. This includes specific kitchen/bathroom caulks that are strengthened with mildew/mold fighters.

2 - Silicone-Based Caulks

These caulks are increasingly becoming common in household application. Silicone caulks offer a slightly higher degree of mold resistance since they are purely inorganic, i.e. they are fully synthetic materials.

Better Adhesion

The substrate features are also mildly better, particularly among perpetually wet and tricky surfaces like ceramic tiles, glass edges and porcelain.

Easier Handling

In terms of workability, silicone caulk is more undemanding than acrylic caulks. It tends to retain a certain degree of softness and doesn’t crack easily. This makes it easier to scrape-off any mold spores and re-patch the silicone caulk strip.


Please note that silicone-based caulk is not as long-lasting as acrylic water-based caulks. It may offer better mold resistance but it presents repeated expenses in terms of more replacements. However, the periodic touching-up needs to be done, every few years. Further, silicone caulk surface isn't very easy-to-clean. Thus, if the mold spots develop, some staining is indicated. A 100% silicone caulk offers a poor surface in terms of retaining paints. These are some of the aesthetic limitations of silicone caulks.