How do I caulk a window?Every article about saving energy tells you that caulking around windows and doors is the first thing to do and the simplest way to keep air from leaking into and out of your home.
That’s only true, of course, if you know how to do it. Here are some simple instructions for using caulk around your home to keep your expensive air-conditioned or heated air indoors where it belongs—and the outdoor weather outside.
- Buy the caulk. You’ll find it at the hardware store in a plastic or cardboard tube or cartridge. Caulk is a sealer made from silicone or paintable acrylic latex. If you want to paint the caulk to match your window frames, buy a brand that’s paintable. If you want to caulk less often, silicone might be a better choice, as it’s less prone to cracking. It’s not paintable, but it comes in a variety of colors. Caulk is a flexible material that you can work into cracks and gaps around your house to fill them in and prevent air from leaking through them into or out of your house. You’ll use about a half cartridge per window.
- Buy a caulk gun. You’ll slip the tube of caulk into the gun to make it easier to work with. Applying caulk directly from the tube is a headache unless you’re just filling in a tiny area. You can buy a caulk gun at a hardware or paint store for less than $15. The more you spend, the less likely the gun will clog. Ask the salesperson at the hardware store to help you choose a gun with features that will make it easier to use. Examples: Some guns come with a handy blade inside the handle grip for snipping off the tip of the caulk tube; others come with an automatic trigger release that prevents you from over-applying the caulk.
- Decide where you will caulk. Any hole, gap, crack or opening on the inside or outside of your house needs caulking. The biggest gaps often are around windows and doors. You can tell if yours are leaking by lighting a match and holding it near the window or door. If the flame flickers, look for leaks and seal them with caulk. You also might want to seal gaps and cracks around exterior light fixtures, outdoor taps and other openings in the outside wall of the house—for exhaust fans and openings where cable and phone lines enter the house.
- Load your caulk gun. Slide the tube of caulk into the caulking gun. Snip the tip off of the tube, making as small a hole as possible so you can control the amount of caulk that squeezes out of it. Secure the tube snugly into the gun. If your caulk comes in a cardboard tube, there might be a second seal at the base of the spout. Puncture it using a nail or the puncturing device on the caulking gun. If your caulk comes in a plastic tube, it probably doesn’t have a second seal.
- Prepare the surface. Clean and dry the area you will caulk. You will apply the caulk between the window frame and the stucco or siding on the outside of your house or at the joint between the frame and the drywall indoors. Scrape away old caulk and loose paint, and scrub off dirt from that area.
- Apply the caulk. Hold the gun at a 45-degree angle and squeeze a small bead of caulk into the tiny line that separates the window frame from the stucco, brick or siding. Use the smallest amount of caulk to do the job. To avoid applying too much, release the trigger before pulling the gun away. A caulking gun with an automatic release will help you here. Then use your finger to smooth the caulk into that tiny opening. Repeat the process until you have caulked all the way around the window frame. (If you’re caulking another kind of hole, like a crack or a gap where a cable goes into the house, push the spout of the tube into the hole before squeezing.) A tip: Wipe away excess caulk as you go. Don’t let it dry before cleaning up your mistakes; caulk is much easier to remove before it’s dry.
- Let the caulk dry for 24 hours, and then paint it to match your window frame.