One of the best ways to improve the energy efficiency of your home and prevent leaks and drafts is to thoroughly seal your windows. For windows that don't open or parts that don't move, the material of choice is caulk. As you start your search for a caulk, you'll find there are a wide variety of choices. Here are a few tips to help you decide what product is best suited for your project.
Latex caulk often is combined with acrylic. You also may find acrylic caulk, which has similar properties to latex. These caulks are water based, which means they contain no volatile chemicals, clean up with soap and water while they are in liquid form. They can also be smoothed by dampening your finger and running it along a bead of caulk. Latex caulks can be painted, and you can also buy pre-tinted caulk. A drawback, latex caulks cannot withstand vast temperature changes or a lot of moisture. Nice thing is if you are wanting to do some sealing inside rather than out, the ease of use and ability to be painted makes them an excellent choice.
Siliconized latex is very like acrylic latex, but it contains a type of silicone. The silicone helps the caulk adhere better. Siliconized latex being water based, is also paintable and tintable, but is more durable than simple latex and can withstand more severe weather conditions. This is a good choice if you want the ease of use latex offers, but are sealing windows from the outside and need something sturdier.
Silicone caulks are made from silicone elastomers, which are very rubbery when the caulk cures. Temperature is not an issue with silicone, and these caulks not only are waterproof, but don't form mildew – which is an excellent choice when caulking on the outside.
There are two kinds: acid-cure and neutral-cure. Acid-cure is designed for nonporous surfaces, so it is preferred when sealing around glass. Neutral-cure is good for use on wood and won't corrode metal or plastic like the acid-cure can, so it can be safely used around surfaces such as vinyl siding. Most silicone caulks cannot be painted. Their flexibility and their exceptional waterproofing make for an excellent choice for exteriors.
Polyurethane caulks are resistant and stick well to many materials, even ones that are not similar, such as plastic and wood. They also are noncorrosive, making them safe to use on many materials. The major drawback of a polyurethane caulk is that it's not resistant to UV light, the sun will cause it to dry out and crack. So, polyurethane needs to be painted to protect the caulk from damage. Another drawback is polyurethane is solvent based, unlike latex caulks, so it needs paint thinner or mineral spirits for working and cleanup rather than water.
By All About Home 3-7-2018