Caulking compound helps keep air, moisture, and insects out of your house and costly heated and cooled air inside. But caulking eventually dries out and requires renewal, so always check for cracked, loose, or missing caulking as part of your spring and autumn maintenance inspections.
The different types of caulking compound, the areas around your house that require caulking, and the application techniques are discussed below.
Types of caulking.
The five basic types of exterior caulking are elastomers, butyl rubber, acrylic latex, non-acrylic latex, and oil base. When making your choice, weigh price against each compound's expected lifetime and consider the kinds of materials to which the caulking must adhere.
Caulking comes in four forms: as disposable cartridges for use with a half-barrel caulking gun, in a can for application with a full-barrel caulking gun or a putty knife, in a small squeeze tube, and as rope caulk. The half-barrel caulking gun fitted with a cartridge is the most popular dispenser, since it's the easiest to use for applying an even bead of compound. Use rope caulk as a temporary filler for very wide cracks or joints- it may not adhere for very long.
CAUTION: Before you buy any caulking, read the label: Some types won't work in cracks or joints less than ¼ inch wide; others work well only in narrow cracks. Take note of any precautions and follow the directions when you're using the product.
Where to caulk.
Generally you'll need to caulk in areas where different surfaces meet. Here are some of the places requiring caulking:
On the roof where one flashing meets another flashing, between flashing and a roof or dormer surface, and where a chimney, flue, plumbing or electrical pipe, attic fan, or skylight protrudes through the roof surface.
On the siding where the siding and trim meet at corners; around window and door frames; between badly fitting pieces of siding; where pipes, framing members, and other protrusions pass through the siding; and where the siding meets the foundation, patio or deck, or any other different part of the house.
It's also a good idea to examine interior window and door frames, especially between sliding door or window tracks and the sill or jamb.
Applying caulking.
Before you can apply new caulking, you'll have to remove the old or damaged sections. First, dig out or chip off all of the old caulking with a putty knife, old screwdriver, or scraper. Then brush the area with a wire brush to remove debris and wipe the surface with a cloth soaked in the appropriate solvent for the type of caulking you're removing.
Before applying the new caulking, check the label to see if you need to prime the surface. Plan to caulk on a warm, dry day when the temperature is between 500 and 700 F. In hotter weather, refrigerate the caulking for an hour or two before use so the compound won't run.
Directions for using a half-barrel caulking gun appear below. It may take a bit of practice to get the bead of caulking to flow evenly. Start by holding the gun at a 45 0 angle to the surface; then, moving the gun across the surface, squeeze the trigger to keep the caulking flowing smoothly Make sure the compound fills the crack completely and overlaps adjoining surfaces evenly. If the crack is deep, apply two beads.
If you're using rope caulk, simply unroll the amount you need and use your fingers to stuff it into the crack.