Caulk and Weatherstrip

Caulking and weatherstripping work well for sealing air leaks around windows and doors. Caulking is for any stationary joint and weatherstripping is for the moving joints of doors and windows.

For air-tightening, you want to caulk from your home’s interior. Standard acrylic latex caulking or siliconized acrylic latex are good choices for interior caulking. Before caulking around window or door casings or baseboard, make sure that these trim boards aren’t loose. If they are loose, re-nail them with finish nails. A cleverly placed finish nail may be the best way to close a large crack.

Caulking cracks in unseen areas is just as important as caulking around baseboards and trim. Look for cracks and holes in closets and thoroughly inspect under cabinets, behind furniture, and at the floor-wall junction under the baseboard.

Caulk your home’s exterior only for stopping rain. The areas most needing caulking are the door and window frames where these trim boards meet the siding. You don’t want to seal joints in the siding itself because it needs to move and breathe.

Weatherstripping doors can slow drafts if you take the time to do a good job. Before weatherstripping, make sure that the door latches properly and that all the hardware is firmly attached. Look first at the hinges to see if there are any loose screws. Then check the door knob and latch. Does the door move back and forth while latched? If so you may need to move the strike plate–the latch attached to the door jamb–to prevent the door from moving while closed.

Choose a high-quality door weatherstrip that will allow some movement because doors expand and contract with seasonal changes in temperature and humidity. Cut the pieces carefully so they meet at the corners. Install a sweep or door shoe at the bottom of the door where it meets the threshold. A good weatherstripping job will also keep dust from blowing into the home.

A door shoe like this one will create a good air seal to the threshold, while allowing clearance over a foot-wiping rug.

The Homeowners Handbook to Energy Efficiency contains more information on caulking and weatherstripping.