DON'T apply caulk when a surface is wet or dirty. A surface that isn't dry and properly cleaned makes it more difficult for the caulk to adhere, which could cause issues like moisture seeping through or peeling soon after it's applied.
Certain places on the exterior of the home should not be caulked, since they'll cut off openings needed for air circulation or drainage. Elegant Painting says these spaces include the gap created when trim boards sit atop the siding, any wood to metal joints, weep holes on windows, and garage door panels.
Caulking adheres better in the warmer weather than in the cold: Ideally, caulking should be applied when the temperature ranges from 40 to 80 degrees Fahrenheit. If this is not the case, silicone may be used to apply it, but you will need to warm the caulk before applying so it will flow smoothly and evenly.
The best time to apply caulk is during dry weather when the outdoor temperature is above 45°F (7.2°C). Low humidity is important during application to prevent cracks from swelling with moisture. Warm temperatures are also necessary so the caulk will set properly and adhere to the surfaces.
Trim boards & Wood Windows
Pretty much all trim joints need to be sealed. This is again to prevent moisture from penetrating into the crack/joint, but it also adds to the overall appearance of the surface.
You don't need to because the trimming is designed to drain moisture away from the window. So, don't seal the joints, or you'll be trapping water inside. Don't caulk your windows shut.
Its optimal lifespan is around 10 years, but an annual or bi-annual inspection is essential to avoid too much deterioration. The exterior caulk of a home must resist the elements.
While some caulk can only be applied in warm weather (40 to 80 degrees Fahrenheit), certain rubber or silicone caulk can be applied in weather as cold as -20 degrees Fahrenheit. The rubber or silicone base prevents the caulk from freezing in cold temperatures.
The best exterior caulks are silicone or silicone-latex. These products are excellent for caulking windows and doors. They can be used on trim and siding, as well.
Removing the old caulk and replacing it with a new bead of caulk instead usually creates a better seal. However, you can effectively caulk over caulk as long as the bottom layer of caulk isn't damaged or moldy. The old caulk should also be clean, dry, and free of oil for the best adhesion.
Polyurethane caulk is made of an organic material that gives it durability and adhesion. However, it reacts poorly if exposed to sunlight, for example on the south wall of your condominium building. It has a life span of 10 to 20 years but may need to be replaced after 2 or 3 years.
Extreme temperatures can also affect your outdoor caulking projects, because the size of the joint or crack you want to caulk can swell when it is really hot. In addition, caulk can't cure properly in extremely hot temperatures. Ideally, you should caulk when the temperature is below 90 degrees.
Caulk peels off in wet settings and damp surroundings. The moisture always present in showers also leads to mold breeding, which further deteriorates the caulk, often leaving a blackish green stain. When the weather conditions are too dry, caulking shrinks and cracks, which leads to gaps in the corners.
Water gets behind the caulk, which then leads to the mold and mildew growth.
Most caulks work best when applied above 40 degrees; use below that temperature can diminish the adhesion, curing and long-term performance of the caulk. So, buy a special low-temperature caulk or one that contains silicone or rubber in its formulation.
Temperature: Caulk cures best at 40 to 80 degrees Fahrenheit. However, you should never apply direct heat to increase the temperature. Freshness: Most caulks have an expiration date. Even if it's in a sealed tube, out-of-date caulk will never cure properly.
When the caulk gets wet, it will not cure properly. The formula that makes up your caulk will not be able to dry and cure or bond to the surface to that you have applied it. Not being able to dry in a timely manner will prevent the caulk from creating a proper seal.
Exterior caulk should be applied thicker than interior caulk in order to endure the more dramatic weather changes. If the caulk is put on with too small of a bead it is more susceptible to cracking and splitting. An area that is difficult to caulk successfully on exteriors is the siding butt joints.
On exterior surfaces that are to be painted, the best approach is to fill the gaps with caulk prior to painting. Having the caulk and paint covering the cracks or gaps, no moisture will be able to penetrate the surface and cause the paint to peel or the materials under it to rot.
Exterior Butyl Rubber Exterior Caulk
Butyl rubber caulk is a popular pick due to its flexibility. Because of this, they are great at sealing exterior joints that experience vast movement. Butyl rubber is also very effective at sealing water in or out. Butyl rubber can be applied to masonry, metal, and gutters.
Movable parts: Don't apply caulk on any movable parts, including the sashes. If you need to improve those seals, consider weatherstripping instead. Weep holes: These holes around the edges of outdoor windows allow moisture that collects behind the frame to seep out.
Don't Caulk Weep Holes, Window Parts or Window Trim
There are holes in siding, windows and trim assemblies that are supposed to be there, so don't caulk them. These holes allow moisture trapped behind the siding and windows to drain out as they're supposed to.
Holes in wood trim are best filled with wood filler. Nail holes in exterior surfaces, just as with cracks or gaps, can be dealt with using a good caulking. Take the time before you apply any paint on your next project to fill all of the gaps, cracks, and nail holes.