How do you seal air gaps in a door?

Stopping drafts from coming through a door can help make your home more energy efficient and comfortable. Air gaps around doors allow cold air to enter in winter and hot air in summer, making it harder to keep your home at a comfortable temperature. Sealing these gaps is an easy and inexpensive way to improve your home’s insulation.

Why seal air gaps in doors?

There are a few key reasons you may want to seal air gaps around your doors:

• Improve energy efficiency – Drafts can account for up to 25% of heat loss in a home. Sealing gaps will help stop warm or cool air from escaping, reducing energy costs.
• Increase comfort – Preventing drafts will help keep indoor temperatures more comfortable and stable.
• Reduce noise – Gaps around doors can let in outside noise. Sealing them can dampen sounds from the street, neighbors, etc.
• Improve indoor air quality – Drafts bring in allergy triggers like pollen and dirt. Reducing them can improve air quality.
• Moisture control – Drafts can transport moisture into your home, potentially causing condensation, mildew growth and other moisture issues.

Where to look for air gaps

Air gaps usually occur in a few key areas around doors. Inspect the following locations to find any leaks:

• Door frame/jamb – Look for gaps between the door frame and wall. Also check the threshold seal at the bottom of the frame.
• Door edges – Air often leaks through gaps between the door and frame, particularly near the latch/lockset.
• Threshold – Check for spaces under the door where air can sneak through.
• Hardware – Gaps around hinges, strike plates, latches, knobs, mail slots and peepholes are also common leakage sites.
• Door sweeps – Worn-out sweeps at the bottom of the door can allow air flow.
• Window seals – Don’t forget to check for leaks around glass panes in doors.

You’ll need to inspect all sides of the door frame to locate any gaps that could be letting air through. Moving your hand around problem areas can help you feel drafts.

Sealing materials

Once you’ve identified any leaks, you can seal them up. Here are some common options:

• Weatherstripping – Adhesive-backed foam or vinyl strips that press against the door to block air flow. Install around the frame or door edges.
• Door sweeps – Vinyl or brush seals that attach to the bottom of the door. Help stop under-door gaps.
• Sealant caulk – Can be used to fill cracks and gaps in the door frame. Look for paintable latex or silicone sealant.
• Spray foam – Expanding foam that hardens to fit gaps. Useful for filling complex spaces.
• Gaskets – Rubberized seals that adhere around door hardware to prevent leakage.
• Threshold seals – Attach to the bottom of the door frame to cover threshold gaps.

The best sealing method will depend on where the leaks are located and how big the gaps are. Combining a few different materials will often give the best results.

How to seal common air gaps

Here are tips for sealing some typical air leaks around doors:

Door frame/jamb gaps

• Clean the door jamb and surrounding wall with a wire brush to remove dirt and debris. This will allow the sealant to properly adhere.
• Apply sealant caulk into any cracks or spaces between the frame and wall. Press the caulk in fully with a putty knife.
• Install foam weatherstripping tape along the doorstop – the part of the frame that the door presses against.
• For larger gaps, cut pieces of backer rod to push into the space before caulking over top.
• Allow the caulk to fully cure before closing the door (usually 24-48 hours).

Around door edges

• Clean the door edges and jamb with rubbing alcohol to remove dirt and oils.
• Cut adhesive-backed weatherstripping foam or vinyl to fit along each door edge.
• Remove the adhesive backing and press the weatherstripping firmly onto the door so it lines up with the door jamb or stop.
• For double doors, add an astragal seal kit to close the gap where the doors meet.

Beneath door

• Sweep or vacuum away any dirt and debris under the door.
• Remove any existing threshold trim if possible. Fill any screw holes with caulk.
• Cut the threshold seal 1-2″ longer than needed and anchor in place with screws. Ensure it sits flush with the floor.
• Spray foam into any remaining gaps around the trim. Let cure completely before walking on it.
• Reinstall threshold trim if removed. Caulk along the edges for a tight seal.

Around hardware

• Remove door hardware like knobs, mail slots, peepholes etc. Take care not to damage door.
• Clean hardware holes with a wire brush and vacuum out dust.
• Fill holes fully with spray foam. Let it cure completely before reinserting hardware.
• Apply weatherstripping gaskets behind hardware plates when reattaching them.

Tips for effective sealing

Follow these tips to ensure your air sealing efforts are effective:

• Do a thorough inspection to locate all possible air gaps. Look on both interior and exterior sides.
• Seal air leaks completely. Any remaining gaps or cracks will still allow drafts.
• Remove any old/ineffective weatherstripping and sweeps before applying new ones.
• Make sure surfaces are clean before applying caulk or weatherstripping for best adhesion.
• Follow manufacturer’s directions for cure times before closing doors or windows.
• Use backer rod for large gaps to reduce the amount of caulk needed.
• Apply sealants smoothly for a seamless air seal and improved aesthetics.
• Make sure door seals are snug but not so tight that the door is hard to latch or open.

Conclusion

Stopping air leaks around doors is one of the most effective ways to increase your home’s energy efficiency. A few inexpensive sealing materials and some DIY handiwork can lead to a noticeable improvement in comfort and energy savings. Pay special attention to the door frame, edges, threshold and hardware when locating and sealing leaks. With proper materials and techniques, you can successfully eliminate drafts and air gaps around your doors.