01 / DOORS
Door sweep, bottom seal or threshold: which part are you actually buying?
Four different parts sit at the bottom of a door and the shops file them all under the same heading. Here is which one your door takes.
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A door sweep screws to the face of the door and hangs below its bottom edge. A door bottom seal wraps around the bottom edge itself. A threshold is the strip on the floor that the door closes onto. A draft stopper slides under the door and attaches to nothing. Sweeps retrofit to almost anything; bottom seals look better; thresholds fix a floor problem; stoppers are for renters.
| Part | Mounts to | Gap it covers | Best for | Downside |
|---|---|---|---|---|
| Door sweep | The face of the door | About 1/8 in to 1 in depending on type | Retrofitting almost any door | Visible on the door face |
| Door bottom seal | The bottom edge of the door | Small to medium, set by the channel | A tidy, hidden result | Usually needs the door off its hinges |
| Threshold | The floor under the door | Sets the height the door closes onto | A worn or missing sill | The biggest job of the four |
| Draft stopper | Nothing — it slides under | Roughly 1/2 in to 1-1/4 in | Renters, interior doors | Drags, and not for exterior use |
Door sweep: the default retrofit
A sweep is a carrier — usually aluminum — screwed to the inside face of the door, carrying a blade or a brush that reaches down past the bottom edge to touch the threshold. Its great advantage is adjustability: the mounting holes are slotted, so you fit it, close the door, and move it up or down until it seals without dragging.
Its disadvantage is that you can see it. On a painted door in a hallway that matters to some people and not to others. Matte white and brown finishes exist precisely for this reason.
Door bottom seal: hidden, and harder to fit
A bottom seal is a U-shaped or channel section that slides onto the bottom edge of the door itself. Nothing is visible when the door is closed, and nothing can be kicked off. The cost is fitting: on most doors you have to take the door off its hinges, and if the door is a fraction too tall you have to plane it before the seal will fit under.
This is the right choice when you are already taking the door off for another reason, or when the appearance genuinely matters. It is a bad choice for a Saturday afternoon fix.
Threshold: when the floor is the problem
If your gap is over an inch, or the sill under the door has rotted, worn or been removed during a floor replacement, no sweep will save you — the part that should be there is missing. A replacement threshold, some of them adjustable in height, is the actual repair. That is a bigger job and one where a carpenter is often cheaper than three failed attempts.
Pick this if
- You own the door, the floor is flat, and you want it fixed today — screw-on sweep with a rubber blade.
- You own the door and the floor is uneven — screw-on brush sweep.
- You rent, or you will not drill — adhesive sweep if the door face is smooth, otherwise a slide-under draft stopper.
- The door is already coming off for painting — door bottom seal, while you have it on the bench.
- Your gap is over an inch or the sill is gone — a threshold, not a sweep.
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 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 |
| 2 | Suptikes Door Draft Stopper Under Door SweepA silicone blade on a strong adhesive strip — the sweep you use when drilling the door is not an option. | Renters and no-drill installs | Roughly 1/8 in to 1 in | CHECK PRICE |
| 3 | Holikme Twin Door Draft Stopper, 34 inA twin-tube stopper that slides under the door and seals from both faces, so it works on a door that gets used all day. | Interior doors, both sides at once | Fits doors up to roughly 34 in wide; slides under a gap of about 1 in | CHECK PRICE |
| 4 | Frost King SB36 Extra Aluminum and Brush Door SweepBristles instead of a blade, which is the difference between sealing a floor that is flat and sealing a floor that is not. | Uneven floors and carpet | Roughly 1/2 in to 1 in | CHECK PRICE |
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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.
Renters and no-drill installs
Suptikes Door Draft Stopper Under Door Sweep
Published gap range
Roughly 1/8 in to 1 in
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A silicone blade on a strong adhesive strip — the sweep you use when drilling the door is not an option.
Where the number comes fromThe seller publishes 2" W x 39" L and no numeric gap range. The blade is trimmed to your gap on install, which is where the flexibility comes from: too little and it drags, too much and it does nothing.
- Blade
- Silicone
- Published size
- 2" W x 39" L
- Mounting
- Adhesive, no drilling
- Trim
- Cut to door width with scissors
- Doors
- Exterior and interior
- Mounting
- Self-adhesive strip on the inside face of the door
What it does well
- No holes, so no deposit argument at move-out
- Silicone stays flexible far below freezing where cheap vinyl stiffens
- Trims to width in one cut
Where it fails
- Adhesive needs a clean, smooth, dry surface — it will not hold on a textured or freshly painted door
- A door that gets kicked open will peel it eventually
- No published gap range; you are sizing it by eye against your own gap
Who this is forRenters, and anyone who wants the draft gone tonight without a drill.
Interior doors, both sides at once
Holikme Twin Door Draft Stopper, 34 in
Published gap range
Fits doors up to roughly 34 in wide; slides under a gap of about 1 in
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A twin-tube stopper that slides under the door and seals from both faces, so it works on a door that gets used all day.
Where the number comes fromHolikme publishes the 34 in width and calls the sweep adjustable. It publishes no maximum gap. The physical limit is the thickness of the connecting membrane — if your door drags on it, the gap is too small, and if the tubes do not touch the floor, it is too large.
- Type
- Twin tube, both faces
- Published width
- 34 in, adjustable
- Mounting
- Slide-under, no fixings
- Moves with door
- Yes
- Washable
- Cover only
- Mounting
- Slides under the door, no adhesive, no screws
What it does well
- Nothing is attached to the door — install is ten seconds and reversible
- Travels with the door instead of being kicked out of place
- Blocks light and some noise as well as air
Where it fails
- Adds friction; a door with a tight gap will drag
- Fabric picks up dust and needs washing
- No published maximum gap figure
Who this is forBedroom, office and basement doors — and any renter who wants zero trace of the fix.
Uneven floors and carpet
Frost King SB36 Extra Aluminum and Brush Door Sweep
Published gap range
Roughly 1/2 in to 1 in
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Bristles instead of a blade, which is the difference between sealing a floor that is flat and sealing a floor that is not.
Where the number comes fromFrost King publishes the 2 in x 36 in size but no numeric gap range. A brush seals by bending, so it tolerates a gap that changes across the door swing — which is exactly the case a rubber blade fails at. Set it so the bristle tips just brush the floor.
- Carrier
- Aluminum
- Seal
- Nylon brush
- Published size
- 2" x 36"
- Mounting
- Screws
- Slotted holes
- Height adjustable after mounting
- Mounting
- Screws through the door face
What it does well
- Brush deals with a floor that rises across the swing; a blade cannot
- Sweeps over carpet and tile transitions without dragging
- Slotted mounting holes let you drop it a few millimeters after the first test
Where it fails
- A brush leaks more air than a compressed rubber blade on a flat threshold
- Bristles flatten with heavy traffic over a few seasons
- Not the pick if you are chasing a fully airtight seal on a flat sill
Who this is forA door that scrapes on one side and swings free on the other, or one that opens onto carpet.
How we picked
- Compare by what each part mounts to, because that is what rules parts in or out for a given door.
- Compare published gap coverage second.
- Recommend per use case: owned versus rented, flat versus uneven floor, exterior versus interior.
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.
Whichever part you land on, measure before you buy: how to measure a door gap takes about a minute and rules out most of the ways this goes wrong. The full ranked sweep list is in best door sweeps.
Questions people actually ask
- What is the difference between a door sweep and a door bottom seal?
- A sweep mounts on the face of the door and hangs below the bottom edge, so it fits without removing the door. A bottom seal wraps around the bottom edge itself, so it is invisible when closed but usually needs the door taken off its hinges to fit.
- Do I need a threshold as well as a sweep?
- Only if the existing threshold is worn, damaged or missing. A sweep seals against whatever the door closes onto — if that surface is sound, the sweep is enough.
- Which one is best for keeping out water?
- A threshold, followed by a bottom seal, followed by a sweep. A slide-under draft stopper is the wrong tool entirely: fabric against a wet sill wicks water into the door.
- Can I fit a door sweep without removing the door?
- Yes — that is the main reason sweeps exist. Mark, cut to width, and screw it on with the door hanging. Only bottom seals and thresholds generally require the door to come off.
Sources
- M-D Building Products — door sweep range and mounting types
- Frost King — door sweeps, bottoms and thresholds category
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 door sweeps, sorted by the gap they actually close
Six sweeps placed by the gap they close, from a slim vinyl blade to a brush for uneven floors.
How to measure a door gap properly
The index-card method, the three-point rule, and how to read your number against a published seal size.
The best door draft stoppers when you cannot drill the door
No-drill stoppers ranked by published fit, including the one that states an actual gap range.