03 / GARAGE
The drafty door between the house and the garage
It is treated like an interior door and it is not one. On the other side is an unheated, unsealed space that is often within a few degrees of outside.
Treat the house-to-garage door as an exterior door: weather strip the frame with a compressible bulb seal, fit a proper door sweep at the bottom, and seal the outlets and switches on the shared wall. Never remove or wedge the self-closer, and never seal a door that is required to be fire-rated in a way that stops it latching.
This door is a genuine anomaly. It is hung, finished and sealed like an interior door, and it separates a heated room from a space that on a January night can be within a few degrees of outdoors. On a lot of houses it is the single largest air leak in the building envelope after the garage door itself.
Safety first, because this door is regulated
- It usually has a self-closing device. That is there so the door cannot be left open into the house. Do not remove it, and do not fit a seal so tight that the closer can no longer pull the door to the latch.
- It is commonly required to be fire-rated in an attached garage. Anything you add must not stop it closing and latching fully.
- Do not add a large brush sweep with a gap under it on the assumption the garage needs ventilation from the house. It does not — the garage should be ventilated to outside, not to your hallway.
- Carbon monoxide is the real risk this door exists to manage. Every seal you add is on the side of safety, provided the door still closes and latches by itself.
The order of work
- 1Check the closer and the latch. A door that does not pull fully to the latch is not sealed by anything you fit. Adjust the closer before buying parts.
- 2Weather strip the frame. Measure the gap between the door and the stop with the index-card method and fit a compressible bulb seal — a 1/4 inch D-section suits most. Full picks in best weather stripping for doors.
- 3Fit a door sweep. Measure the gap under the door at three points. On a garage-side door with a concrete step, a rubber blade sweep is usually right; on an uneven floor use brush. See best door sweeps.
- 4Do the outlets and switches on the shared wall. The wall between house and garage is an exterior wall thermally, and its electrical boxes leak like any other. Foam gaskets take two minutes each — see best outlet gaskets.
- 5Re-test the closer. With the new seal compressing, confirm the door still swings shut and latches on its own. If it does not, your seal is too thick.
The rest of the shared wall
While you are there, the wall itself is worth a minute with an incense stick. Look at the ceiling line if there is a room above the garage, the joint where the garage drywall meets the house wall, and any point where a pipe or cable passes through. These are the leaks nobody thinks about because they are on the garage side, where nobody stands still long enough to feel a draft.
And do the garage door itself. Sealing the house-to-garage door while the garage is effectively outdoors just moves the boundary — the garage will still be cold, and the wall between will still be losing heat. Bottom seals and side and top seals are the two jobs that change the garage's own temperature.
Quick picks
Ranked for fit, not for hype. Tap a row to jump to the full write-up, or go straight to the listing.
| # | Product | Best for | Gap range | Price |
|---|---|---|---|---|
| 1 | Frost King EPDM Rubber Self-Stick Weatherseal Tape, D-Section, 5/16 in x 1/4 in x 17 ftEPDM in a hollow D — the profile that keeps sealing at minus ten where foam tape has already gone hard. | Medium frame gaps | Published 1/4 in thick; compresses to seal gaps of roughly 1/8 in to 1/4 in | CHECK PRICE |
| 2 | Frost King A79/36H Premium Aluminum and Reinforced Rubber Door SweepA screw-on aluminum carrier with a reinforced rubber blade — the version of this part that survives a winter of a storm door slamming into it. | Exterior doors, screw-mounted | Roughly 1/4 in to 3/4 in | CHECK PRICE |
| 3 | Frost King OS6H Foam Outlet and Switch Sealers, 2-1/2 in x 4 inFire-retardant foam gaskets cut to the standard 2-1/2 by 4 inch plate — the part, not a novelty. | The standard outlet gasket | Fits standard US outlet and switch plate openings | CHECK PRICE |
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Medium frame gaps
Frost King EPDM Rubber Self-Stick Weatherseal Tape, D-Section, 5/16 in x 1/4 in x 17 ft
Published gap range
Published 1/4 in thick; compresses to seal gaps of roughly 1/8 in to 1/4 in
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EPDM in a hollow D — the profile that keeps sealing at minus ten where foam tape has already gone hard.
Where the number comes fromFrost King publishes the section dimensions exactly: 5/16" wide by 1/4" thick, 17 ft long. A hollow D seals across roughly half to full its stated thickness, which is where the 1/8-1/4 in working figure comes from.
- Profile
- Hollow D
- Published width
- 5/16 in
- Published thickness
- 1/4 in
- Published length
- 17 ft
- Material
- EPDM rubber
- Mounting
- Self-adhesive onto the door stop
What it does well
- EPDM stays flexible in cold, which is the entire point of a winter seal
- Published dimensions to three fractions — you can actually match it to a measurement
- Compresses without taking a permanent set the way open-cell foam does
Where it fails
- 17 ft is one door frame; a house needs several rolls
- Adhesive still needs a clean, smooth surface
- Thicker than a V-strip, so it can stop a tight door from latching
Who this is forA door stop or window sash with a visible, consistent gap you have measured.
Exterior doors, screw-mounted
Frost King A79/36H Premium Aluminum and Reinforced Rubber Door Sweep
Published gap range
Roughly 1/4 in to 3/4 in
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A screw-on aluminum carrier with a reinforced rubber blade — the version of this part that survives a winter of a storm door slamming into it.
Where the number comes fromFrost King does not publish a numeric working range for this sweep. The 2-inch face and the rubber blade's projection put it in the quarter-inch-to-three-quarter-inch band once mounted; the blade must touch the threshold under light compression, not bend flat. Measure before you buy.
- Carrier
- Aluminum
- Blade
- Reinforced rubber
- Published size
- 2" x 36"
- Mounting
- Screws (supplied)
- Maker's claim
- Lifetime guarantee on weathersealing ability
- Mounting
- Screws through the door face, above the threshold
What it does well
- Screws, not adhesive — nothing to peel off in July
- Cuts down with a hacksaw for a narrower door
- The rubber blade is replaceable in practice; the carrier is what lasts
Where it fails
- You are drilling into the door face — renters should look at an adhesive or slide-on option
- No published gap range, so measuring first is not optional
- Aluminum shows a hard line on a painted door; the finish choice matters
Who this is forAn exterior door you own, with a gap you can see daylight through and a threshold that is basically flat.
The standard outlet gasket
Frost King OS6H Foam Outlet and Switch Sealers, 2-1/2 in x 4 in
Published gap range
Fits standard US outlet and switch plate openings
#ad · how we are funded · no live price right now
Fire-retardant foam gaskets cut to the standard 2-1/2 by 4 inch plate — the part, not a novelty.
Where the number comes fromFrost King publishes the gasket size (2-1/2 in x 4 in) and that the foam is UL-listed fire retardant plastic. There is no gap range: the gasket seals the plate to the wall, and the leak it stops is the one around the box.
- Published size
- 2-1/2" x 4"
- Material
- U.L. listed fire retardant plastic foam
- Quantity
- 6
- Install
- Behind the faceplate
- Visible after install
- No
- Mounting
- Behind the faceplate, no tools beyond a screwdriver
What it does well
- The fire-retardant rating is the spec that matters on anything going behind a faceplate
- Completely invisible once the plate is back on
- Two minutes per outlet with one screwdriver
Where it fails
- Only helps where the box is genuinely leaking — many are not
- Six per pack does one wall, not a house
- Does nothing about the much larger leaks around windows and doors
Who this is forExterior-wall outlets on the windward side, where you can feel air at the plate.
How we picked
- Treat this door as an exterior door throughout, because thermally it is one.
- Products placed by published section against the measured gap, exactly as on a front door.
- Safety constraints on this specific door are stated before any sealing advice.
We have not tested these products and we do not claim to have. The full method, including what we refuse to claim, is on how we pick.
Questions people actually ask
- Should I weather strip the door between my house and garage?
- Yes. Thermally it is an exterior door, and it is often the leakiest one in the house. The only constraint is that it must still close and latch on its own if it has a self-closer, which most attached-garage doors are required to have.
- Can I put a door sweep on my garage entry door?
- Yes, and it is one of the higher-value fixes in the house. Measure the gap at three points first. If the door opens onto a concrete step, a rubber blade sweep works; if the step is uneven, use a brush sweep.
- Why is the door to my garage so cold?
- Because the garage is effectively outdoors and the door was specified as an interior door. It typically has thin weatherstripping if any, a large gap at the bottom, and an uninsulated shared wall behind it.
- Is it safe to seal the house-to-garage door completely?
- Yes — the garage should be ventilated to outside, never into the house. The one rule is that the door must still close and latch by itself. A fire-rated self-closing door that no longer latches has been made less safe.
Sources
- Frost King — published EPDM D-section weatherseal dimensions
- Frost King — outlet and switch sealer material and UL listing
Every specification on this page traces to a published manufacturer or retailer listing. Where a maker publishes no working gap range, we say so rather than estimating one.
Read next
The best weather stripping for doors, by published thickness
V-strip, D-section, silicone and foam placed against the gap each published thickness can actually seal.
Sealing the sides and top of a garage door
The jambs and header are usually a bigger hole than the bottom, and about twenty dollars to close.
The best outlet gaskets, and an honest word on what they fix
Two minutes and a screwdriver per outlet — genuinely worth it on exterior walls, and honestly small.