Get cracking on caulking

Tips on materials and methods for sealing your windows and doors


Caulking season is upon us. Time to seal those gaps in windows, around doors and other places to reduce the amount of cold air seeping into your house, which contributes to higher energy bills. Here's a quick primer on the right materials and the right way to do the job:

GETTING STARTED -- Get the right caulk for the job. Latex, acrylic and silicone are the three most common caulks; the first two are easier to apply and clean up, but they are not as long-lasting as silicone. Acrylic and latex can be painted, but paint will not adhere to silicone.

Silicone sets up more quickly than the other two, is better for filling gaps that may expand and contract, and can be used indoors and out. Latex and acrylic should be used to fill cracks that expand or contract more than one-eighth of an inch; read the label to see whether the latex or acrylic caulk in question can be used outdoors as well as in.

DOING THE JOB -- Applying caulk not only involves mastering the caulk gun but learning how to prepare the surface so the caulk adheres properly.

First, remove old caulk with a utility knife and make sure the surface is clean and completely dry. Then insert the cartridge into the caulk gun and cut the nozzle at a 30-degree angle, making certain the hole in the cartridge matches the width of the gap you are filling.

How do you keep caulk from going outside the gap? Professionals have a trick: Put a piece of masking tape over the length of the area to be filled, then carefully cut down the center of the tape to expose the gap. Push the caulk gun away from you, which forces the caulk into the gap and makes a good fit. Once caulk is applied, remove the tape.

Some hard-to-reach spots become more easily accessible if you slip a straw into the hole in the caulk cartridge. To smooth the finish, use a Popsicle stick or a plastic spoon; some pros even suggest using an ice cube.

To remove caulk that goes where it doesn't belong, dip your finger in water with a little dishwashing detergent and wipe away.

DON'T DO THIS -- Don't wait until the caulk dries to begin cleaning up any excess, because it is likely to involve some scraping. What you're scraping may get scratched, and you could foul up your nice caulking job.

WHAT IT COSTS -- Caulk can run from $3 to $10 a tube, depending on what it's made of and the length of its warranty. A high-end manual caulk gun can run up to $50. But the one you want to buy costs $7 to $12 -- if it gets caulked up quickly and hard to use, you won't need a bank loan to replace it.

Alan J. Heavens is a reporter for the Philadelphia Inquirer.

Caulking tips

Thoroughly clean all areas to be caulked. With a utility or putty knife, remove old caulk and paint. Brush away loose material.

Hold the gun at a consistent angle; 45 degrees is best. When it's right, caulk is immediately forced into the crack as it comes out of the tube.

Try to caulk in one straight, continuous stream; avoid stops and starts.

Make sure caulk adheres to both sides of a crack or seam.

Release the caulking gun trigger before pulling it away to avoid over-application. A caulking gun with an automatic release makes this much easier.

[U.S. Energy Efficiency and Renewable Energy Clearinghouse]


Caulking gun

Tubes of caulk

Masking or painter's tape

Utility knife, putty knife

Clean rags

Hand broom or paintbrush

Plastic straw

Popsicle stick or plastic spoon

Water source

Dish detergent

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