Caulking Double-Hung Windows

Winter may be right around the corner in your neck of the world. But fall is the very best time to get a jump on the hawk. Caulking, if used properly can keep winter out of, warmth inside of, your home. Using caulking on double-hung windows can contribute to your first line of defense.

Caulk all the windows while the air temperature is above 45 degrees. The weather should also be dry. Take note of how many windows you have. All the windows should be caulked to keep the house free of window drafts. Purchase a good outdoor clear caulking. One tube should cover 2 �½ to 3 windows, more or less depending on the overall average size of your windows. Before applying caulking scrape and brush all chipped paint and debris from around window casings and frames. Sweep away the remains. This is to insure a good seal between the caulking and the building material. Cut off the tip of the caulking tube at a 45 degree angle where the opening will only allow a �½ inch bead of caulking to squeeze through.

The caulking is only for the outside of the upper windows and not the inside nor the bottom windows. Use weather-stripping for the inside and lower windows.

Start by covering the seams between the top of the top window frame and the touching window casing down to both sides to the bottom of the upper window. Your overall object is to cover all seams to prevent air from bellowing through. As you apply the caulking take a flexible, narrow and plastic knife or spatula that has a rounded edge to smooth out the bead of caulking. Keep the spreading instrument sprayed with a lubricant like WD-40 to keep the caulking from sticking to it and to provide a smoother spread.

You might want to smooth out the caulking every 12 inches or so to avoid a heavy over applications of the caulking. Constantly check for gaps in the caulking reapplying it as you go. Applications should only cover seams that are no more than one eighth to one quarter of an inch wide. You should also spread only as much caulking as twice the width of the seam being covered.

You will want to apply caulking in a bead (line) around the window molding over the seam where it meets the brick, siding or other building material. You should have a continuous bead from the top side to side and on both sides from top to bottom of the window casing. Spread some caulking along the bottom of the upper window on the right and left ends where the windows are against the window channel to seal those seams as well. Finally check all the window panes of each window, this time the upper and lower frames alike. If there are seams or gaps between the panes of glass and the frame seal these with a relative amount of caulking.

Tools Needed:

Note pad

Gloves (latex or rubber)

Pencil ladder

Caulking gun



Wire brush

Narrow spreading instrument (plastic knife or spatula, etc)


Cloth (dampened for wiping)

Broom & Dustpan

Bucket (for water for rinsing and dampening)

Leave a Reply

Your email address will not be published. Required fields are marked *

6 − four =