How to Seal Gaps Around Windows and Doors to Keep Out Pests in Winter

 

If you want to stop pests like insects and mice from sneaking indoors during winter, you need to seal all the small cracks and gaps around your windows and doors. Sealing these gaps prevents cold air and bugs from coming inside. Here’s exactly how you do it, step by step, using simple tools and materials—most of which are easy to find at any hardware store.

 

Start By Inspecting Everywhere Carefully

 

Walk slowly around all windows and doors inside and outside your house. Look for any visible cracks, gaps, or holes—no matter how small. Gaps are common where different materials meet, such as where the window frame meets the wall, or where doors meet their frames or the floor. Also check around mail slots, pet doors, and where cables or pipes go through the wall. If you feel a cold draft with your hand on a cold day, that's a gap pests can use.

 

Clean the Surfaces Before Sealing

 

Use a damp rag, vacuum, or brush to remove dust, cobwebs, old caulk, or loose paint from the area around the gaps. This helps the new sealant stick properly so it lasts longer.

 

Choose the Right Materials for Sealing

 

• Caulk: This is a thick, flexible material that comes in a tube. It’s perfect for sealing stationary gaps around window and door frames where nothing moves. Use latex or silicone caulk for indoor gaps; for outside, look for “exterior” caulk for weather resistance.
• Weatherstripping: This is a strip of rubber, foam, felt, or vinyl with adhesive backing. It's designed for moving parts, such as the edges of doors and windows that open and close.
• Door Sweeps: These attach to the bottom of exterior doors to close the gap between the door and threshold, stopping drafts and crawling insects or mice.

 

How to Apply Caulk Successfully

 

• Cut the tip of the caulk tube at a 45-degree angle for better control.
• Load the tube into a caulking gun (most hardware stores sell them cheaply).
• Place the tip into the gap and gently squeeze the trigger, moving along the crack to fill it with a smooth bead of caulk.
• Smooth it with your fingertip (wet your finger first) or a special tool, pressing it firmly into the crack.
• Let it dry according to the instructions on the tube—usually several hours. Don’t touch or paint it until fully dry.

 

How to Install Weatherstripping

 

• Choose weatherstripping that matches the width and thickness of your door or window’s edge.
• Measure the edge you want to seal, then cut the weatherstripping to fit with scissors.
• Peel off the adhesive backing (on self-stick types), then press it firmly onto the clean, dry surface. For nailed or screwed types, follow the package instructions.
• Check that the door or window closes tightly but easily afterward—adjust if it’s too hard to close.

 

How to Fit a Door Sweep or Threshold

 

• Measure the width of the door’s bottom and cut the sweep to fit.
• Most sweeps screw or snap into place—follow the packaging instructions.
• Make sure the sweep just touches the floor, closing the gap but not dragging too much.

 

Final Tips to Ensure a Thorough Seal

 

• After sealing, check again on a windy day or at night with a flashlight from outside. If you can see light or feel air movement, you missed a spot.
• Don’t forget to seal gaps where pipes, wires, or cables enter your house—use caulk or expanding foam for these holes.
• Replace old, cracked caulk and worn weatherstripping every year or two for best results.

 

Summary: Keep Pests and Cold Air Out for Good

 

By thoroughly inspecting, cleaning, and sealing all gaps using caulk for still joints and weatherstripping or sweeps for moveable parts, you block the easiest entry points for winter pests and cold drafts. This not only keeps out bugs and rodents but also saves on heating bills and makes your home more comfortable all season long.