Painting over sealants can be tricky as not every type of sealant can be painted over due to its compatibility with different paint types. Therefore, it is important to find one that is paintable and has the correct finish, so the caulking work you do won’t stick out like a sore thumb and start separating or peeling off. You also should ensure that they meet the industry specifications and are accredited by the relevant authorities. Additionally, it should produce low volatile organic compounds, provide superior bonding capabilities, and have high durability in its material. Read on for the five considerations to make before painting sealants.
Polyurethanes are usually high-performing sealants that provide excellent adhesion strength, durability, great wear and tear resistance while still retaining its elastomeric properties, meaning the texture in its cured form should have some flexibility and elasticity. More importantly, there should be minimal shrinkage, so your paint job will not start cracking and separating years down the road. Conventionally, polyurethane sealants are best paired with high-performing latex and acrylic paints due to their high compatibility. However, before you start painting them, you should always let these polyurethane sealants cure for no less than three days to prevent flash-curing them.
Following the application, the polyurethane sealants will start chemically curing. During this process, it will be reactive with moisture, which can be an issue when you unintentionally use excess paints. When this happens, you may find that the surface of the caulking will start bubbling and appearing very uneven. Additionally, although you may be painting over an old polyurethane sealant surface, you should wipe the surfacer down with a compatible solvent to remove any debris, dirt, dust, and other contaminants that may affect the performance.
If you are considering painting over silicone sealants, chances are you won’t have the most optimum results due to their physical properties and incompatibility. Silicone sealants may be one of the most high-performing caulks out there in the market today. Still, they are generally not paintable due to their slippery surface and incompatibility with rubber and latex paints. After painting over them, the results you can expect are having separation and cracking issues, which can cost a costly painting job to achieve an even surface. While many of them may market themselves as paintable, you should fully examine and understand the materials the sealants contain before purchasing them.
These mixed material sealants, usually comprised of Silylated Polyether (SPE), Silylayted Polyurethane (SPUR), and Silyl Modified Polymer, use a combination of different polymers and materials. They work ideally with acrylic paint to achieve a smooth and clean finish for the best results. Compared to polyurethane, their benefits are that they don’t require as much time to cure and can be painted over shortly after they have completed their chemical cure. Of course, you have to allow a good first layer of skin to form before painting over as it protects the sealant from deforming and becoming uneven. For this reason, it is also one of the top holy grails for many quick renovation works due to the efficiency it can provide.