Acrylic latex caulking in a caulking gun.
Acrylic latex caulking is one of several types of caulking used to seal gaps between building materials. It is water soluble when wet and can be painted. Acrylic latex is also inexpensive and makes a good all-purpose caulking. Unlike silicone caulk, it’s easy to apply and remove when it needs to be replaced.
The composition of acrylic latex caulking includes acrylic polymers, water, latex and fillers. This particular blend of ingredients adheres very well to rough or porous materials such as masonry, wood, drywall and plaster. It’s not suitable for filling large cracks, but it’s fine for small gaps in things like wood trim. This seal cures, or dries, as the water evaporates and has a slight odor until it cures, which is not as strong as the strong vinegar smell that a silicone seal typically gives off when it dries.
Caulking is used to seal gaps between building materials.
Some types of acrylic latex caulk contain silicone, or at least small amounts of it. This is primarily an attempt by the manufacturer to combine some of the qualities of silicone caulking with those of acrylic latex. It works to an extent, but these seals also often have a high filler content, which tends to detract from their overall performance.
Acrylic latex caulking is best suited for indoor use because of its low tolerance for direct sunlight and extreme temperatures. Because it contains no oils, the seal can be painted, leading some to call it a painter’s seal. In fact, there are a variety of seals to suit almost every need, including those that resemble brick mortar, concrete and asphalt. For these applications, a type of foam called a support bar can be inserted into the crack for stability and to take up space before caulking is applied.
Caulk has been used for many decades, but it was not until the 1960s that acrylic latex was used. This is in part because latex must be chemically derived, and processes like these have only been perfected in the relatively recent past. More recent chemical processes have also led to the creation of chemical mixtures with interesting properties. Some special seals are available, custom-made for use on cold and damp surfaces, as well as surfaces that expand and contract with extreme temperatures, such as aluminum gutters.