Weatherproofing Doors: Seal Drafts and Improve Home Efficiency
Your exterior doors are the largest moving parts in your home’s building envelope. Every time you open and close a door, you create an opportunity for air to leak around the edges. Over the course of a year, the gaps around a single door can let enough conditioned air escape to significantly impact your energy bills.
Weatherproofing doors is one of the most cost-effective home improvements you can make. The materials are inexpensive, the tools are basic, and the installation takes an afternoon. The payoff is immediate — you feel the difference the first time you walk past a door that no longer whistles with cold air.
Understanding Door Leaks
Where Doors Leak
Doors leak air at four primary locations. The gap between the door and the jamb on the hinge side, the gap on the latch side, the gap at the top of the door, and the gap at the bottom between the door and the threshold.
The bottom gap is usually the largest and most noticeable. Door sweeps and threshold seals address this gap. The side and top gaps are sealed with weatherstripping attached to the door jamb.
Detecting Door Drafts
The hand test works for doors as it does for windows. On a cold day, run your hand around the door edges. You will feel cool air entering through gaps. The incense stick test also works — light an incense stick and watch the smoke pattern around door edges.
The dollar bill test checks your door seal. Close the door on a dollar bill. If the bill pulls out easily without resistance, the weatherstripping is not compressing enough to create a seal. Try this at several points around the door.
Seasonal Considerations
Wood doors expand and contract significantly with humidity changes. Your door may seal perfectly in spring but develop gaps in winter when the wood shrinks. Weatherstripping must accommodate this movement.
Plan to inspect and adjust door weatherstripping annually. The transition between heating and cooling seasons is an ideal time. Seasonal adjustment is normal and expected for wood doors.
Weatherstripping Types
Adhesive Foam Tape
Foam tape is the simplest weatherstripping solution. It comes in rolls with a peel-and-stick backing. Choose the thickness that matches your gap — the foam should compress about fifty percent when the door is closed.
Foam tape works best for gaps up to one-quarter inch. It is inexpensive and easy to install but wears out faster than other types. Plan to replace foam weatherstripping every one to two years.
V-Strip
V-strip is a flexible plastic or metal strip that forms a V shape. It creates tension when compressed and provides an effective seal for irregular gaps. V-strip is more durable than foam and lasts three to five years.
Install V-strip on the door jamb, not on the door itself. The open end of the V should face the interior of the house. Cut the strip to length and press it into place. Some V-strip types require nailing or stapling.
Door Sweeps
Door sweeps attach to the bottom of the door and seal the gap between the door and the threshold. Types include bristle sweeps, rubber sweeps, and vinyl sweeps. Choose a sweep appropriate for your floor surface and the gap size.
Bristle sweeps work well for uneven thresholds and carpeted floors. Rubber and vinyl sweeps provide a tighter seal for smooth thresholds. Measure the door width and cut the sweep to length with a hacksaw.
Thresholds
The threshold is the bottom strip of the door frame that the door closes against. Adjustable thresholds have a vinyl or rubber insert that can be raised or lowered to improve the seal.
Inspect your threshold condition. A worn or damaged threshold may need replacement rather than adjustment. Threshold replacement requires removing the door, making it a more involved project.
Reinforced Silicone
Reinforced silicone weatherstripping has a silicone sealing bulb mounted on a rigid backing strip. It is the most durable option and provides the best seal. It conforms to uneven surfaces and remains flexible in extreme temperatures.
Install reinforced silicone weatherstripping by screwing the backing strip to the door jamb. The silicone bulb compresses when the door closes and creates an effective seal. This type can last ten years or more.
Window Caulking and Sealing covers complementary sealing techniques for windows.
Installing Weatherstripping
Measuring and Cutting
Measure each section of the door frame carefully. The hinge side, latch side, and top each need separate pieces. Cut weatherstripping slightly longer than the measurement and trim it for a tight fit.
For door sweeps, measure the door width at the bottom. Transfer the measurement to the sweep and cut it with a hacksaw or tin snips. File any rough edges smooth.
Attachment Methods
Foam tape weatherstripping uses adhesive backing. Clean the surface thoroughly, peel the backing, and press the tape into place. Apply firm pressure along the entire length to ensure good adhesion.
V-strip and reinforced silicone attach with small nails, staples, or screws. Position the weatherstripping so it contacts the door surface when closed. The seal should be snug but not so tight that the door is difficult to close and latch.
Door sweeps attach with screws through pre-drilled holes in the sweep. Position the sweep so it contacts the threshold or floor surface. The door should swing freely without dragging.
Testing the Seal
After installation, test the seal by closing the door and checking for light visible around the edges. Have someone stand inside with the lights off while you look for light leaking around the door from outside.
Test with a dollar bill at several points around the door. The bill should have resistance when pulled out. If it slides out easily, the weatherstripping needs adjustment or replacement.
Door Threshold Maintenance
Adjusting an Existing Threshold
Many thresholds have adjustment screws that raise or lower the threshold insert. Locate the adjustment screws, typically found on the top surface or at the ends of the threshold.
Adjust the threshold so it contacts the door sweep when the door is closed. The seal should be snug without preventing the door from latching. Make small adjustments and test the door operation after each adjustment.
Replacing a Worn Threshold
Threshold replacement is a more involved project. Remove the interior and exterior trim around the door. Remove the door from its hinges. Remove the old threshold and clean the area.
Install the new threshold according to the manufacturer’s instructions. Apply a bead of exterior-grade caulk under the threshold before installation. Replace the door and trim. Adjust the new threshold for proper contact with the door sweep.
Threshold Cap Replacement
If only the threshold cap is worn — the top surface that contacts the door — you may be able to replace just the cap rather than the entire threshold. Measure the threshold dimensions and purchase a replacement cap.
Remove the old cap and clean the threshold base. Install the new cap with screws or adhesive as directed. Adjust the height to match the door sweep.
Storm Doors
Benefits of Storm Doors
Storm doors provide an additional layer of protection and insulation for exterior doors. They reduce air infiltration, protect the primary door from weather, and provide ventilation with interchangeable glass and screen panels.
A quality storm door can improve the energy efficiency of an older door significantly. The air space between the storm door and the primary door creates an insulating barrier.
Weatherstripping Storm Doors
Storm doors have their own weatherstripping that needs maintenance. The weatherstripping around the storm door frame and at the bottom of the door wears out and needs periodic replacement.
Check the storm door closer — the mechanism that controls how the door closes. Adjust the closer so the door closes firmly against the weatherstripping. A storm door that does not close fully does not provide its intended benefit.
Storm Door Maintenance
Clean storm door tracks and lubricate moving parts annually. Check the glass panels for cracked or failed seals. Replace damaged screens promptly. Inspect the door frame for rot or damage, especially at the bottom where moisture accumulates.
Garage Door Sealing
Garage Door Bottom Seal
The bottom seal of your garage door is the largest air leak in most garages. Over time, the seal compresses, cracks, and loses effectiveness. Replace the bottom seal when you see light under the closed door.
Garage door bottom seals come in different profiles. Remove a section of your existing seal and match it at a hardware store. Slide the new seal into the retainer channel on the bottom of the door.
Garage Door Perimeter Weatherstripping
The sides and top of the garage door need weatherstripping as well. Install vinyl or rubber weatherstripping on the door frame that contacts the door surface when closed.
Garage door weatherstripping reduces drafts, prevents pests from entering, and improves the energy efficiency of attached garages. This is especially important if the garage is heated or if living spaces are above the garage.
Garage Door Threshold Seal
A garage door threshold seal attaches to the floor under the closed garage door. It creates a seal that prevents water, pests, and drafts from entering under the door.
Install the threshold seal with adhesive and screws. The seal should align with the bottom of the closed door. When the door closes, it compresses the seal and creates a watertight barrier.
Garage Door Maintenance covers comprehensive maintenance for garage doors and their components.
Interior Door Draft Prevention
Door Draft Stoppers
For interior doors that lead to unconditioned spaces like basements, attics, or garages, a draft stopper at the bottom of the door reduces air movement. Door draft stoppers are fabric tubes filled with insulating material.
Place the draft stopper against the bottom of the closed door. Some stoppers have adhesive strips that hold them in place. For doors that are not used frequently, a draft stopper is an effective and low-cost solution.
Keyhole and Mail Slot Covers
Keyholes and mail slots in exterior doors are often overlooked sources of drafts. Keyhole covers slide over the keyhole when the key is not in use. Mail slot covers block the slot from the inside.
Check that these accessories are in good condition and properly installed. Replace damaged covers promptly. A mail slot that does not seal properly lets significant cold air into the entry area.
FAQ
What is the best weatherstripping for exterior doors?
Reinforced silicone weatherstripping provides the best combination of durability and sealing performance. It lasts ten years or more, conforms to uneven surfaces, and remains flexible in extreme temperatures. V-strip is a good alternative for tighter budgets.
How do I stop air from coming under my door?
Install a door sweep on the bottom of the door. Choose a sweep that contacts the threshold surface. For gaps larger than one-half inch, adjust the threshold or install a new threshold with a taller profile.
Should I weatherstrip interior doors?
Weatherstrip interior doors that separate conditioned living spaces from unconditioned areas like basements, attics, garages, and enclosed porches. Interior doors between conditioned rooms do not need weatherstripping.
How often should I replace door weatherstripping?
Replace foam tape weatherstripping every one to two years. Replace V-strip every three to five years. Reinforced silicone weatherstripping can last ten years or more. Inspect all weatherstripping annually and replace it when it shows signs of wear or deterioration.
Can I install a storm door myself?
Storm door installation is a moderate DIY project. It requires basic tools and the ability to lift and position the door. The most critical steps are ensuring the door is plumb, level, and properly flashed to prevent water intrusion. If you are not confident in your installation skills, hire a professional.
Fall Home Checklist includes door weatherproofing in the broader schedule of winter preparation tasks.