The best door thresholds for exterior doors are the ones that shed water outward, seal the gap under a closed door, and survive a decade of rain and freeze-thaw cycles without warping. A threshold is the bottom edge of an exterior door assembly, and it is the single most common failure point on the whole unit. When it stops sloping or its seal goes hard, water finds its way into the wall cavity and starts quietly rotting the framing behind your drywall.
We compared ten thresholds over weeks of handling, install planning and spec-checking for this 2026 guide, and the shortlist covers every real case: flat aluminum saddles for commercial doors and wheelchair access, adjustable aluminum-and-hardwood sills for uneven openings, composite inswing units for wide walls, and a purpose-built outswing model with an integrated foam seal. The picks below are ordered by how much confidence I would put behind them, not by brand name.
Every threshold below appears in this table with the specs that actually decide a fit: material, the width and height you will measure in your opening, and how the seal is made. Width is the number people get wrong most often, so match it to your wall thickness before anything else.
| Product | Specifications | Action |
|---|---|---|
| M-D Building Aluminum Flat-Profile Threshold |
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 M-D Adjustable Aluminum and Hardwood Threshold |
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| Endura Inswing Threshold Composite Cap and Base |
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 SFNSM Aluminum Floor Transition Threshold |
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 Inbar Hardware Adjustable Aluminum Threshold |
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 Barzen Outswing Bumper Sill with Q-Lon Seal |
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 Randall V-4 Aluminum Threshold with Vinyl Seal |
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| Frost King Fluted Aluminum Saddle Threshold |
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 Tandefio Two-Pack Aluminum Saddle Threshold |
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 Blulu Aluminum Swing Door Threshold |
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Aluminum
5 inch wide x 1/4 inch thick x 36 inch long
Hardware included
This is the threshold I keep coming back to for anyone who just needs something that works. It is a flat aluminum saddle, 36 inches long, 5 inches wide and a quarter inch thick, and it has been on the market long enough that replacement parts and advice are everywhere. The aluminum is genuinely rigid rather than thin and springy, which is what you want across the middle of a door opening where foot traffic concentrates.
Because the profile is only a quarter inch tall, it is the least likely option here to trip a walker, a mower deck or a wheelchair caster. If you are working on a garage side entry, a screen door, or anything where the frame sits low, that low rise is the whole point. It is also UL fire rated, which matters if the door it sits under is part of a rated assembly. I have to flag one thing, though: this is a saddle, not a sealing sill. It caps the joint and stops drafts at floor level, but it does not have a vinyl or foam strip compressing against the door bottom.
Two things come up repeatedly in buyer feedback. The first is packaging: the finish sometimes arrives scratched, mottled, or with foreign material stuck to the underside, and a few people report a piece that was bent in the box. None of that affects function, and a scuffed flat aluminum saddle is easy to live with or scuff further. The second is hardware, with screws occasionally arriving loose or absent, so it is worth having a few extra fasteners on the bench before you start.
On the plus side, buyers report that the listed dimensions are accurate, that it installs in minutes, and that it is available in silver and bronze across a range of widths and lengths. Several people use it as a sill plate or to cap a cracked joint rather than as a primary weather seal. It is the threshold I would hand to a homeowner who wants one decision that does not need revisiting.
Choose it when you want a low, flat, durable surface over anything that leaks, and your priority is durability rather than a compression seal. Commercial side doors, garage entries, sliding-door openings, and accessibility-sensitive thresholds all suit it. Our garage door opener guide covers the matching hardware on that side of the wall if you are rebuilding a garage entry.
It also works well as a base under a taller sealing sill if you want a stable, wide bearing surface, which is a trick several buyers describe using it for.
Skip it if you need a hard seal against drafts, insects and driven rain, because there is no insert in this profile to do that sealing. It is also the wrong answer for a rough opening with a big height variation, since a fixed saddle cannot adjust to an uneven sill. If your wall is unusually thick, check that 5 inches covers your jamb depth.
Aluminum with oak base
5-5/8 inch wide x 1-1/8 inch high
Adjustable riser
This is the adjustable answer, and adjustable is the feature that matters when an old opening has settled. The riser moves from 1-1/8 inch up to 1-3/8 inch, which is 1.38 inches of maximum gap fill, and that range covers a lot of the slightly-off geometry you find in a house that has been through a few decades of freeze-thaw. The body is aluminum with a solid oak base at 5-5/8 inches wide and 36 inches long.
The wood base does real work here. It gives the door something solid to close against instead of metal on metal, which is a softer landing and a quieter one. It is also the part that most often disappoints: buyers report the oak arriving brittle, chipped, or poorly finished, held on with staples, and a fair number of people reinforce it with construction adhesive and finish nails as a matter of course. This unit has more one-star reviews than any other in the group, and almost all of them trace back to hardware or wood condition rather than to the concept.
Check your kit before you start. Missing bolts, nuts and T-nuts are the most common complaint, and the instructions for where the washers go are described as vague. The adjustment screws also sit off-center on the piece, which means the seal loads unevenly across the width and you may want to check the fit at both jambs after tightening. Bring your own hardware and a tape measure, not just the box.
Even so, this stays near the top of the list because the adjustability solves a problem nothing else in this group solves. If your door gap varies along the opening, or your sill is not level, this is the one that will actually seal. It is also one of the most reviewed adjustable hardwood-and-aluminum sills available, so there is a large body of real-world install experience to draw on.
This suits a settled opening where the gap under the door is inconsistent, and a homeowner who is comfortable with a slightly more involved install than a screw-down saddle. It is a good fit for an older 36-inch exterior door where the original sill is worn but the jambs and frame are still square.
It also suits anyone who prefers a wood bearing surface under the door for appearance or for the feel of closing. Just reinforce the oak base before you install if the piece looks dry or rough.
If you want a turnkey install, this is not it. The incomplete hardware kits and vague washer instructions are recurring, and you will likely be sourcing fasteners separately. It is also a poor match for a wet, exposed corner where an unsealed wood base will take on moisture, since the oak is real hardwood and real hardwood eventually softens. Buyers wanting zero rot risk should look at the composite pick further down.
Composite cap and base
7-13/16 inch wide x 1-3/8 inch high
Adjustable to 1-5/8 inch
At 7-13/16 inches wide, this is the widest profile in the roundup, and that is exactly why it earns a place. Standard 2×4 walls give you a 4-9/16 inch jamb, 2×6 walls push you to 5-5/8 inches, and then there are the thick-wall and double-stud entryways where nothing off the shelf covers the opening. This one does, and it is built for inswing doors, the most common configuration in residential construction.
The material story is the real headline. Both the cap and the base are solid composite rather than wood, so there is no oak to rot, swell or delaminate. The cap is textured and finished to read as oak, which matters if the rest of your door is a wood-look unit and you do not want a metal band across the bottom. The base runs the full length, and the adjustable height runs from 1-3/8 inch to 1-5/8 inch, so it absorbs some of the same unevenness the adjustable aluminum unit handles.
Two practical notes. The unit ships uncut, at roughly 36-1/2 inches, so you need a saw and a straightedge before it will go in. And the finish is raw mill-finish aluminum with no applied coating, which means it scuffs easily if you drag something across it during install. Neither issue is difficult, but both cost you five minutes you might not have budgeted.
The buyers who keep this one are the ones with a wide opening and a rot concern. That combination is unusual enough that most people assume no product covers it. This does, and the composite construction means you are not painting a maintenance schedule into your entryway.
Wall thickness is the number that trips people up. If your jamb depth is beyond 5-5/8 inches, a standard sill leaves you with exposed framing and a gap you have to caulk. This width spans most of those thicker walls in a single piece. It is worth measuring the total wall thickness at the door, not just the jamb board, since drywall and sheathing add to the depth.
For entryways where the wall is very thick, a sill extension is the other route, and we cover that in the buying guide. If you are choosing a new door for a wide opening rather than repairing one, our fiberglass entry door picks are worth a look in parallel.
It is an inswing part, so an outswing door will not work with it despite the generic dimensions. The mill finish will not stay pristine in a high-traffic entry, and the oak-look cap is a composite imitation rather than real wood, so if you are matching genuine hardwood elsewhere in the frame you will notice the difference up close. It is also a premium-priced part, which is hard to justify on a standard 2×4 wall.
Aluminum alloy
3 inch wide x 36 inch long
Pre-drilled holes
This is the one to buy when you want to close a joint between two surfaces rather than build a sealing sill. It is a fluted aluminum transition strip, 3 inches wide and 36 inches long, in a corrosion-resistant alloy, with a widened 0.6 inch top support section that gives it more load capacity than a plain strip. Think of it as the threshold equivalent of a T-molding for a floor change.
The install is the easiest in the group. Three pre-drilled holes line up with the supplied expansion screws, so there is no layout work and no hunting for a fastener that matches. It cuts down to length for a narrower doorway, and the fluted top gives you grip in wet conditions. The non-slip low-profile surface also keeps it friendly to a wheelchair or a walker, which is the same reason the flat commercial saddle is popular.
The tradeoff is width. At 3 inches it is the narrowest profile in this roundup, and narrow coverage means it does less to bridge a gap or cover a damaged sill edge than a 5-inch or 6-inch saddle would. It is also light at just over a pound, so it does not carry the same sense of rigidity as the heavier commercial aluminum pieces. Buyers who wanted a heavy-duty feel sometimes notice that immediately.
That said, for a porch step transition, a shop-to-garage joint, or an interior-to-exterior floor change where a draft is the complaint rather than driven rain, this is a clean, quick answer. The 4.5-star average across more than a hundred reviews reflects a product that simply does one thing and does it without drama.
Reach for this when the problem is a gap, a trip edge or a draft across a floor change, and you do not need a compression seal against a swinging door. It is a good match for screened porches, sunrooms, basement entries and any spot where the surface is level and the issue is purely the joint.
It also works as a repair cap over a cracked or worn sill edge where the frame itself is still sound. Because it is aluminum, it will not absorb moisture the way a wood strip would.
It will not stop water coming under a closed exterior door, because there is no seal to compress against the door bottom. It is also too narrow for a thick wall, and too low to bridge a real height change. If you have an inswing door with a leaking sill, the height and width here are simply not enough, and you should be looking at a hardwood or composite sill instead.
Black aluminum
4.56 inch wide x 1.37 inch high
Hidden screw design
The reason this one is on the list is cosmetic and practical at once. The screw holes are hidden, so once it is fastened you see a continuous black aluminum face instead of a row of fastener heads collecting dirt. The black finish also does an excellent job of hiding scuffs and wear marks in an entryway, which matters for a surface people look at every single day on the way out of the house.
Dimensions are 36 by 4.56 by 1.37 inches, and the piece weighs a substantial 8 pounds, which is a fair signal of how much aluminum is in it. The insert is a rubber strip that is firm rather than floppy, and it compresses against the door bottom to block drafts, water and insects. For a pre-hung door with a slightly irregular gap, that gives you a tighter closure than a fixed saddle.
The honest criticism is the adjustability. Buyers say the height barely changes across what is advertised, so manage your expectations: it helps with a small variation, not a dramatic one. The documentation is also light, and if you are drilling into concrete you will want a proper hammer drill and tap screws rather than relying on what is in the box. The weight cuts both ways, since it is reassuring on the wall and tedious to trim.
Even with those caveats, the hidden-screw design is a genuine improvement over exposed-fasthead models, and the black finish is the most attractive of any threshold in this group. It suits a modern entry where the door is dark and a bright silver strip would look like an afterthought.
This is a good fit for a contemporary entry with a dark or stained door, where a black band across the bottom coordinates better than mill-finish silver. It suits anyone who does not want visible fastener heads and who already has a decent masonry setup if the substrate is concrete.
If your draft problem is more about the double-door style of entry, our draft guard picks for double doors address that side of the problem, since a seal along the head and jambs does as much work as the bottom one.
If your opening has a significant height variation, this will not close the gap the way a true adjustable riser does. The 4.56 inch width is also narrower than the 5-inch and 6-inch options, so it covers less of a thick-wall jamb. And at 8 pounds with modest adjustability, it is a lot of mass for what you get.
Oak base with aluminum top
4.5625 inch wide x 0.75 inch high
Integrated Q-Lon foam seal
Outswing doors are the awkward case. Almost every threshold sold for residential entry is built for an inswing, so an outswing door tends to end up with a mismatched strip, a pile of caulk, or an unresolved draft. This is a unit made specifically for a pre-hung outswing, and that alone puts it near the top of this list for anyone with that configuration.
The build is oak wood base, aluminum top with a V-shaped face, and a 5-degree bevel that slopes water away from the interior. The kerf-in Q-Lon foam seal is integrated into the piece, which is the detail that matters most: it compresses against the bottom of the door and blocks drafts, insects and moisture without you adding a separate door sweep. At 4.5625 inches wide and 0.75 inch high, it is a compact, fairly low profile that will not foul the door or catch a shoe.
The ridged underside grips most flooring without adhesive, and the piece cuts cleanly with a hacksaw if your opening is narrower than 36 inches. The oak base sits under the door where the weather rarely reaches it directly, and the aluminum top handles whatever does get past.
The geometry reverses. On an inswing door the threshold sits inside the opening and the door closes down onto it. On an outswing door the door swings away from the interior, so the seal has to sit on the face the door closes against from the outside, and the sill has to be shallow enough that the door can swing past the interior casing. Getting that wrong is why outswing owners end up trimming jambs.
Before you order, confirm which way your door actually swings when viewed from outside. If you are unsure, the sweep and weatherstripping on the frame will tell you, because they are always on the interior side of an outswing unit.
The 0.75 inch height is fixed, so an uneven or dropped sill will leave you with a gap at one end. There are no pre-drilled holes, which means you are choosing your own fasteners and layout, and on some smooth flooring the ridged underside still wants a bead of adhesive. And because this is a fixed-height, one-function part, it will not serve as a flat transition strip for a non-door opening.
Aluminum with vinyl insert
3-1/4 inch wide x 7/8 inch high
Fits 5/8 to 3/4 inch gap
This is the simplest answer to the most common residential situation. The Randall V-4 is a 36 inch aluminum threshold, 3-1/4 inches wide and 7/8 inch high, built for a door bottom that sits between 5/8 inch and 3/4 inch above the floor. That gap range covers a large share of standard pre-hung residential doors, which is why this configuration keeps selling.
The seal is a premium vinyl insert bonded into the aluminum body. Vinyl is the right material here because it stays flexible in cold weather and does not take a set, so it keeps compressing against the door bottom year after year instead of going hard and brittle the way an aging plastic insert on an original manufacturer sill does. Owners report it blocking drafts, dust, moisture and insects effectively, which is the full job of a threshold seal.
It is made in the USA, the mounting holes are pre-drilled, screws are included, and the instructions are printed on the packaging. There is no measurement, layout or drilling to do before the install, which makes this about as close to a set-and-forget replacement as this category gets.
Measure the gap from the floor to the bottom of your closed door at three points: hinge side, middle and latch side. If all three land between 5/8 inch and 3/4 inch, this is a direct fit. If they differ, you do not have a fixed-height threshold problem, you have a door sag problem, and an adjustable riser will serve you better.
The gap is also where the door sweep and bottom weatherstripping live. If your existing sweep is hitting the floor or binding, that is a separate repair, and no threshold will fix it.
Skip it if the opening is thick-walled, since 3-1/4 inches is narrow and will leave the jamb exposed. Skip it if you need to cover a damaged or decayed sill edge across a wider span. And if your gap is outside the 5/8 to 3/4 inch window, this fixed profile will leave you with either a gap or an interference, and no amount of caulk makes either one right.
Fluted aluminum
5 inch wide x 1/4 inch high x 36 inch long
Pro Grade
The Frost King CS514/36 is a fluted aluminum saddle, 5 inches wide, a quarter inch high and 36 inches long, sold as a Pro Grade part. The flutes running along the top are not decoration, they are traction, and they are what makes this piece easier to walk on when it is wet. The quarter-inch rise keeps it effectively flat relative to anything else in this roundup.
Five inches of width is the useful part. It covers a 2×6 jamb comfortably and gives you a broad bearing surface across the opening, which makes it a solid choice for a door that gets opened and closed constantly. Buyers consistently rate it well for coverage and for holding up outdoors, and the steady 4.6 average over 95 reviews reflects a product with no dramatic strengths and almost no reported failures.
One thing to plan for: it is listed as raw material. The mill finish is unfinished aluminum, which scuffs easily and will not match a finished door, and you should assume you are supplying your own fasteners rather than finding a bag of screws in the box. Bring exterior-rated screws sized to your substrate and you will be fine.
You are buying a durable, correctly sized piece of shaped aluminum with a consistent profile and a finish that will last as long as the door does. That is a narrow pitch, and it is a real one. For a garage side door, a back entry, or a pre-hung door whose gap happens to suit a quarter-inch rise, this is a sensible, low-risk replacement that does not ask you to think about composite cap geometry or riser adjustment.
If appearance matters, note that raw mill aluminum will oxidize to a dull grey over time and will show scratches early. Accepting that is usually easier than it sounds, because a saddle is a working part of the assembly rather than a decorative element.
It will not seal against a door bottom, because there is no insert, so it fixes drafts and trip edges but not driven rain through a closed door. It is not adjustable, so the door gap must be comfortable at a quarter inch. And the missing hardware means a first-time installer needs a short trip to the hardware store before starting, which slightly undercuts the value proposition for a quick job.
Aluminum
6 inch wide x 1/4 inch high x 36 inch long
Two per pack
This one solves a small but real annoyance: a double door needs two thresholds, and buying them separately means two deliveries and two chances for one to turn up scratched. The Tandefio pack contains two 36 inch aluminum saddles, each 6 inches wide and a quarter inch high, and at 6 inches this is the widest flat saddle in the roundup. That extra half inch over a standard 5-inch profile covers more of a thick jamb and bridges more of a damaged sill edge.
Construction is the same fluted aluminum saddle concept as the narrower options, with a low anti-slip surface and a quarter-inch rise that keeps the transition flat. Buyers also point out that it helps stabilize an outer door and reduce sag, which is a reasonable secondary benefit if your door has been dropping at the latch side for a while.
It cuts to any length, so a 32 inch opening is straightforward. The 4.5 average across 74 reviews reflects a straightforward, well-sized part with very little drama in the feedback.
The complaints are all about the fasteners that come with it. Several buyers report that the supplied screws are too short to bite into thick carpet or a shag pile, which is a real problem because a saddle that pulls loose under a swinging door will rattle. Others note that the screw finish does not match the silver threshold, which is cosmetic but visible. Neither issue is difficult to solve, and buying your own exterior screws removes both at once.
On value, this does cost more per piece than a comparable single unit, so if you have one standard door and no plans for a double, the math works against you. If you have a double door, or you want a spare for a rental or a shop, the pack format is genuinely convenient.
It suits a double door entry where both leaves need a matching threshold and you would rather have the pair arrive together. The identical profile on both sides also looks more considered than mismatched pieces, which is worth something at a front entry where visitors see it.
Keeping the second one is a reasonable hedge if you are replacing a threshold now and know the other side of a pair is going eventually. For interior-versus-exterior door planning, our interior door guide covers the parts of a door assembly that do not face weather.
If you have one door and nothing else to use a spare on, this is more money per threshold than you need to spend. Remember too that a flat saddle seals nothing, so if water is coming under a closed door this width will not fix it. And if your flooring is thick carpet, plan on supplying longer screws rather than trusting the ones in the pack.
Aluminum with wooden insert
5-5/8 inch wide x 36 inch long
1.02 inch high
This is a swing-style threshold, and the detail that separates it from the flat saddles is the wooden insert fitted underneath. That insert closes the void between the aluminum and the floor of the opening, which does two things at once: it stops cold air moving through the cavity, and it blocks the drafts that a bare metal saddle always lets by. The aluminum body handles the weather side, and the wood handles the insulation side.
Dimensions are 36.02 by 5.55 by 1.02 inches, which puts it in the same width class as a standard 2×6 jamb, and it is rated for both residential and commercial exterior use. At just over 5 pounds it has the feel of a solid piece rather than a stamping, and the black finish suits a dark door or a modern entry. Owners rate it well for the combination of sealing and build quality.
The reservation most people raise is the wood itself. A wooden insert sitting in an exterior position is exposed to rain, UV and freeze-thaw, and over a long service life it can swell, check or lose its seal. That is the same durability trade-off the composite unit solves by not using wood at all, so the right answer depends on how wet your entry gets and whether you are willing to inspect it periodically.
There is also no adjustment range, so a 36 inch length with a fixed height has to match your opening. And it costs more than the simpler aluminum sills even though the sealing is comparable, which is a fair criticism for a straight replacement job.
It suits an entry where cold air movement is the primary complaint rather than water ingress, and where the existing opening is a standard 36 inch with a 5-5/8 inch jamb. The wood insert genuinely improves the thermal break at the bottom of the door, which is where a lot of a conditioned home loses heat in winter.
It also suits someone who wants a substantial, finished-looking part with a black exterior and does not want to glue or screw a separate seal strip onto the underside after install.
If the threshold is fully exposed to driving rain or salt air, the wood insert is the weak point and the composite cap-and-base unit is the better long-term answer. Skip this if your door gap is irregular, since a fixed-height part will not seal consistently. And if the cheapest flat saddle would solve your problem, this is spending money on insulation you may not need.
The wrong threshold is usually chosen because three questions were never answered: which way does the door swing, how thick is the wall, and how big is the gap under the door. Get those right and most of the fit problems disappear. Here is how to work through them, and what to do when the leak is not where you think it is.
Water under a closed exterior door has four usual causes, and they are worth checking in order because the cheapest fix is usually first. A flat or inward-sloping threshold is the most common; water has nowhere to go but in. Next is a failed seal, where an original plastic insert has gone hard, cracked or lifted and stopped compressing. Third is a missing or breached pan, meaning the flashing or sill pan under the threshold was never installed or has been punctured. Fourth is rotted wood, where the sill itself has gone soft and holds water against the framing.
The test that separates them is simple. Hose the opening for several minutes with the door closed, then open it and look underneath with a flashlight. Water sitting on top of the threshold points to slope or seal. Water tracking along the framing and out through the interior face points to the pan or a rotted sill. A steady cold draft with no water at all is almost always a dead seal, which is a much cheaper repair than a full replacement.
Stand outside the house and look at the door. If it swings toward you, it is an inswing door and you need a standard threshold that sits inside the opening. If it swings away from you into the house, it is an outswing door and you need a part built for that geometry, with the seal on the face the door closes against from outside.
This one decision eliminates the most common purchase mistake. A standard inswing sill on an outswing door will either foul the interior casing or fail to seal at all, and no amount of sealant fixes the geometry. If you are choosing a threshold for a new door, matching the swing matters as much as matching the size. For a wider survey of door hardware around the opening, our door sweep guide covers the bottom seal that works alongside whichever threshold you install.
Aluminum is the most rot-proof choice and the default for good reason. It does not swell, warp or harbor moisture, it cuts with a hacksaw, and it is available in every width and profile imaginable. Its weakness is appearance and thermal conductivity, since bare metal conducts cold straight into the house and shows every scratch.
Hardwood, typically oak, gives you a warm surface and a soft landing for the door, and it looks right on a wood-look unit. It is also the material that fails eventually, because water finds the end grain and the staple holes. In a fully exposed position, seal the ends.
Composite solves the rot problem while keeping the wood look, and it is the best answer for a wide or exposed opening. Vinyl is not a frame material, it is a seal material, and it is the right choice for an insert because it stays flexible in cold weather instead of going brittle.
Measure the jamb depth, not the wall thickness on paper. Stand at the door and measure the full depth of the frame from the interior face to the exterior face, including drywall and exterior cladding. Standard 2×4 construction gives roughly 4-9/16 inches, 2×6 gives about 5-5/8 inches, and thick or double-stud walls can exceed 8 inches. Match the threshold width to that number with a little tolerance, not to the door leaf width, which is a different measurement entirely.
Then measure the gap under the closed door at the hinge side, the middle and the latch side. If the three numbers agree and fall in a range a fixed sill covers, buy the fixed sill. If they differ by more than a quarter inch, buy an adjustable riser. And measure the opening width at the top and the bottom, since out-of-square jambs are common in older houses.
The threshold is the last piece of a water-management system, not the whole system. Below it you want a sloped sill pan that drains outward, and under that, properly lapped flashing that runs down the face of the wall and out past the trim. Water should never be able to sit in the assembly, and every joint should shed rather than pool.
For sealant, use a quality exterior-grade sealant at the gap between the new threshold and the existing flooring or tile, and a separate bead at the frame-to-threshold joint. Both need to be tooled, and both need to be compatible with the flooring material. Silicone-based products hold up best where the joint will flex, which a threshold joint does as the door cycles. If your tile line sits higher than the new threshold, that gap is the one to close carefully, since it is the path water takes to the subfloor.
Beyond a standard jamb width, your options are a wide-profile sill, a sill extension, or a sloped stone sill. A sill extension widens a narrower threshold to cover a thick wall while keeping the seal where the door needs it, which is the most common retrofit. A sloped bluestone or slate sill with a pan underneath handles very wide openings beautifully but requires more work and a proper pan to be correct.
On accessibility, the practical target is a rise you can cross without catching a caster, and 1/4 inch is the flatest useful profile in this roundup. The quarter-inch commercial saddle and the low-profile transition strips meet that comfortably. The taller hardwood and composite sills, at 7/8 inch to 1-3/8 inch, are fine at a front door but a poor choice at a threshold someone crosses in a wheelchair every day. If you are replacing more than the threshold, accessibility is worth weighing alongside everything else here.
Aluminum is the most rot-proof choice for an exterior door threshold because it does not swell, warp or hold moisture, and it can be cut with a hacksaw to fit an opening. Hardwood such as oak looks warmer and gives a softer landing for the door, but it eventually fails as water reaches the end grain. Composite keeps a wood appearance with no rot risk, and vinyl works best as a seal insert rather than as a frame.
A door sill is the bottom framing member of the door unit and can mean the whole structural bottom of the frame. A door threshold is the surface-mounted or rabbeted component sitting on top of that sill, spanning the opening and carrying the seal. Retailers use the two words interchangeably, so the practical difference is whether you are replacing the strip under the door or rebuilding the frame.
Yes, in most cases. Open the door, protect the interior floor, then remove the door sweep or bottom weatherstripping. Pry out the old threshold with a thin-bladed pry bar, working from one end so you do not damage the jamb. Clean out the old sealant and foam, fit the new threshold to the opening width, fasten it with exterior-rated screws, and re-caulk the joint to the flooring and frame. The frame usually stays in place.
Work through four causes in order of likelihood. First, a flat or inward-sloping threshold, which you fix by adding a sill pan or a ramped sill that drains outward. Second, a failed seal, which you fix by replacing the worn vinyl or Q-Lon insert. Third, a missing or breached pan, which needs proper flashing under the threshold. Fourth, a rotted wood sill, which has to be cut out and replaced before any new part will help.
Yes, an exterior door needs a threshold, even if the door itself has a bottom seal. The threshold sheds water out of the opening, closes the floor joint so drafts and insects do not pass, and provides the bearing surface the door closes against. A door cut down and fitted with a bottom sweep can work in a sheltered location, but it does nothing about water running across the opening, which is the failure that causes rot.
The M-D Building flat-profile aluminum threshold is the pick for most people, because a quarter-inch rise, a 5 inch width and a rigid aluminum body solve more real problems than anything else in the group, and the volume of real-world use behind it is unmatched. If your wall is thick or your opening is wide, the Endura composite inswing unit is the one that fits and the one that will not rot. If your door is an outswing, the Barzen sill with the integrated Q-Lon seal is purpose-built and far easier to source than anything else.
Whatever you choose, measure the jamb depth and the gap under the door before you order, confirm which way the door swings, and check whether the leak is a slope problem rather than a seal problem. That last step is the one that saves people the most money, and it costs you ten minutes with a flashlight and a hose.
