Window caulking: Interior and exterior caulking
Starting with the right tools is an important step in caulking windows. A good caulking gun is essential to every home repair toolkit. Caulking guns can be found at hardware stores and are used to load the caulk cartridge and apply caulk. Look for a smooth-rod, dripless caulk gun that has a spring-loaded mechanism to deliver even pressure with minimal force. This prevents messy excess caulk and ensures even, consistent application.
The first decision you need to make when caulking both interior and exterior windows is what type of caulk to use. Generally, caulk comes in a few basic types: acrylic latex, siliconized latex, silicone, and polyurethane.
Acrylic latex caulk is water-based, which means fewer hazardous chemical ingredients and easy clean-up. While not particularly weather- or temperature-resistant, acrylic latex can be painted or purchased pre-tinted to complement existing color schemes. It is best suited for interior applications.
Siliconized latex is similar to acrylic latex but contains silanes, a type of silicone. It has many of the same properties as acrylic latex but has greater resistance to weather and creates more durable bonds. This makes siliconized latex a good choice for exterior window caulking.
Silicone caulk is highly resilient against temperature and mildew, making it suitable for kitchen, bath, and HVAC applications. It comes in acid-cure and neutral-cure varieties. Acid-cure works best for non-porous materials like glass. Neutral-cure is better for wood, metal, or plastic, as well as common materials such as vinyl siding. Silicone is highly waterproof, which is great for tubs and sinks.
Polyurethane caulks are solvent-based, not water-based, which makes them quite powerful. It can be a bit more challenging to work with them than with silicone caulks. Polyurethane caulks work well for bonding most common housing materials but can break down over time when exposed to UV radiation.
Silane-modified polymers (SMPs) are excellent adhesives for use on almost all substrates, combining properties of silicones and polyurethanes. Try an SMP glue for a powerful, elastic bond on windows that dries clear and resists weather, dirt, UV radiation, and dust