Caulking is used to keep water from entering where it is not wanted. Outside your home caulking can be used at wood trim, windows, doors and electric and cable penetrations. Inside your home caulking is used at painted trim, countertop backsplashes, as well as around tubs and showers.
Caulking has many uses and can also refer to the application of flexible sealing compounds to close up gaps in buildings and other structures against water, air, dust, insects, or as a component in firestopping. In the tunnelling industry, caulking refers to the sealing of joints in segmental precast concrete tunnels, commonly by using concrete.
Although not a high-tech operation, caulking can be tricky. The instructions on the compound cartridge should be followed. The following are a few important tips to provide your client:
For good adhesion, clean all areas to be caulked. Remove any old caulk and paint using a putty knife or a large screwdriver, a stiff brush, or a special solvent. Make sure the area is dry so you won’t seal in moisture.
Time and weather will shrink and dry caulking so that it no longer provides a good seal. As routine maintenance, check the caulking and make needed repairs. Caulking compounds and dispenser guns are available at hardware stores and home centers, such as Home Depot or Lowe’s. Read the manufacturer’s instructions carefully to be certain that you select an appropriate caulk for the intended purpose.
After removing old caulking ensure joint is clean and debris free. Allow the cleaned joint to dry for a day or more unless the product is approved for wet applications. Press an open-cell foam backer rod into joints wider than 1/4 inch (6 mm) or deeper than 1/2 inch (12 mm) so the joint is about half as deep as it is wide. Never fill a deep joint. Doing so wastes caulk and makes a good, permanent bond less likely.
Caulk in one straight, continuous stream, if possible. Avoid stops and starts. Send caulk to the bottom of an opening to avoid bubbles. Make sure the caulk sticks to both sides of a crack or seam. Release the trigger before pulling the gun away to avoid applying too much caulking compound. A caulking gun with an automatic release makes this easier. If caulk oozes out of a crack, use a putty knife to push it back in.
Silicone caulk is the type of caulk that people tend to be most familiar with. It is usually clear in color and has a rubbery, flexible texture when dry. For the past 20 years or so, the majority of caulks on the market have been made out of silicone. Because of its durability and effectiveness on a wide variety of surfaces, silicone continues to be a popular choice today. It is especially useful on non-porous surfaces, including metal and plastic. And because it stays flexible after it is dry, silicone caulk rarely breaks or cracks as a result of extreme temperatures or rapid temperature changes. This makes it perfect for filling gaps around windows and doors.
During our home inspection we routinely inspect for missing or cracked caulking. These are typically found on windows, doors or flashings. Potential for damage can be minor to major, as in roof flashings where missing caulking can allow water into your home.
