Ever walk into a hardware store to browse caulks and find yourself confused? You’re not alone. Every job can require a different product, and you need to consider many different factors. Is the caulk for outside or inside? How much moisture is there going to be? What temperature does it need to withstand and be applied at? What materials is the caulk being placed on? To give you a better idea of the different types of caulk out there, here is a small list of the major types and some of their notable qualities:
These products are usually excellent when it comes to flexibility and curing very clearly. They are thereby useful for most external joints that will contract and expand with the weather. The fact that they can be applied in cold and damp climates also helps. They can also be painted over with many water-based paints. A solvent-based synthetic-rubber caulk will be quite adherent to most surfaces (i.e. substrates) and is even resistant to mildew. Because they shrink a lot, are flammable until they are fully cured, and contain a high volume of VOCs (volatile organic compounds) they are generally not a good idea for indoor environments. On the other hand, their ability to stretch, recover their shape, and withstand weather makes them ideal for outdoor caulking jobs (ex. a log home).
A caulk with a water base is essentially made of latex and will also include acrylic and vinyl. Their low amount of odour, nontoxicity, and ability to be cleaned up with water make them a solid choice for interior caulking. They are a breeze to apply and modify and will adhere to the majority of materials; however they are best applied in warm, dry climates. They can even be painted over. You want to keep in mind that water-based caulks can be very different depending on the product. Each one’s performance can vary wildly and some will even have flexibility and weather-resistant traits that make them suitable for outdoor caulking. Be prepared to do your homework on each product. Just keep in mind that latex caulks are often the best choice for indoor caulking and the outdoor compatible caulks will cost you more money.
A long-time staple of the caulking market, silicone products come in a variety of forms that have made them applicable for pretty much any surface you could think of. When it comes to hard surfaces in particular (e.g. glass, porcelain, tile, and metal), silicone is your ideal product. Silicone is also resistant to cold weather, mildew, UV rays, and mold. On the other hand, silicone products do not adhere well to wood, can be difficult to work with and clean up, and can deteriorate easily after being initially torn. Most products can also not be painted. Surprisingly silicone caulks are nontoxic despite the fact that they are usually very odorous.
While these account for some of the most common types, there are some other sealants on the market including hybrid products, which chemically engineered in such a way that they cannot truly be categorized by their bases. Hopefully all of this information will help you the next time you find yourself feeling lost in the caulk aisle of your local Toronto hardware store!