Here’s how to properly seal your exterior side garage door to keep out water, drafts, and pests — while allowing the door to function smoothly and safely:
1. Check the Door Frame and Threshold
- Inspect the door jamb (the sides and top of the frame). It should be straight, undamaged, and free from rot or corrosion.
- Ensure the threshold (bottom sill) is level and intact. If it’s uneven, air and water can sneak in even with new seals.
2. Install Quality Weatherstripping
Use compressible weatherstripping on the sides and top of the door:
- Common types include foam tape, rubber bulb, or vinyl compression seals.
- Close the door and check for light leaks—if you see daylight, you need to adjust or replace the seal.
- It should press gently against the door when closed—tight enough to seal but not so tight that it makes closing difficult.
3. Add a Door Bottom Sweep or Shoe
- At the bottom of the door, attach a door sweep or aluminum door shoe with a rubber or vinyl insert.
- A sweep should just touch the threshold — enough to stop water and drafts but not drag hard on the floor.
- If your garage floor is uneven, use a dual-fin sweep or adjustable threshold to fill the gaps.
4. Seal the Threshold
- If water tends to pool near the door, consider a raised threshold seal (a small ramped rubber strip adhered to the floor).
- Use silicone or polyurethane caulk to seal where the threshold meets the concrete to prevent seepage.
5. Seal and Paint the Door
- If your door is wood, paint or seal all sides, including the bottom edge, to prevent swelling or rot.
- For metal doors, inspect for rust and repaint or touch up as needed.
6. Ensure Adequate Ventilation
Even though the door should be sealed, the garage itself still needs airflow:
- Maintain vents high and low on opposite walls.
- If the door is in a detached garage, cross-ventilation is especially important to reduce moisture and mildew.