Exterior Door Threshold Replacement — Replace a Rotted Door Sill
The threshold rocks when you step on it, the cap is cracked, the wood under it is black, or the sweep has nothing to seal against. We replace the sill and set it so the door closes tight.
JMB Builders does exterior door threshold replacement across the Twin Cities metro. We pull the old sill or threshold, check the subfloor under it, set a sill pan, fit a new adjustable aluminum threshold or a wood sill cut to the jambs, bed it in sealant, and adjust it to the door sweep so it seals. Rotted jamb bottoms found at the same time are spliced. Priced per door, quoted from photos within one business day.
- Priced per door; threshold, sill pan and adjustment
- Adjustable aluminum or wood sill to match
- Quote from photos in 1 business day
- Licensed MN contractor BC809005
The threshold is the sill of the door: the piece the door closes down onto, usually aluminum with an adjustable cap on a modern entry door, or solid oak on an older one. It takes every footstep, every snow shovel and every drop of water that runs off the door. When it cracks, sinks, rots or comes loose, cold air comes under the door, water gets to the subfloor, and no sweep can seal against it.
Replacing it means pulling the old threshold out from between the jambs, cleaning down to the subfloor, and looking at what is there. Solid subfloor gets a sill pan and the new threshold. Soft subfloor gets cut out and patched first. The new threshold is cut to fit tight between the jamb legs, bedded in sealant, screwed down, and the cap is adjusted up to the sweep so the door closes with an even seal across its width. On an older house with a wood sill, we cut a new oak or composite sill to the same profile.
JMB Builders replaces exterior door thresholds across the Twin Cities metro, on front doors, back doors, garage service doors and the door from the garage into the house. It is a half-day job for one door, and the sill pan we add is the part that keeps the next one from rotting.
What you supply
- A photo of the threshold from outside and one from inside, and a close-up of any cracked or soft spot
- A photo of the bottom of the door and the sweep
- Whether the door is steel, fiberglass or wood, and whether the threshold is aluminum or wood
- The threshold if you already bought one; otherwise we bring the right one
What JMB supplies
- Removal of the old threshold or wood sill, and any subfloor patch needed under it
- Sill pan with end dams under the new threshold, sealed to the subfloor
- Adjustable aluminum threshold cut to the jambs, or a wood sill milled to match the old one
- Threshold bedded in sealant and fastened, cap adjusted to the door sweep
- New sweep on the door when the old one is worn, so the two seal together
- Rotted jamb bottoms spliced at the same time when they are soft
- Photos of the finished threshold in your job folder
How it is priced: per door
Quoted in writing from your photos within one business day. What moves the number:
- Aluminum adjustable threshold vs. a wood sill that has to be cut to a profile
- Subfloor under the threshold: solid vs. soft and needing a patch
- Whether the jamb bottoms are also rotted and need a splice
- Door sweep replaced at the same time or reused
- Flooring inside the door: a transition strip that has to come up and go back
- Number of doors in the same visit
A photo from outside, one from inside and a close-up of the worst spot, plus the door type, is enough to quote it firm.
How long it takes
One threshold with a sill pan: two to three hours. Add an hour or two for a subfloor patch or a jamb splice. Two doors in a morning.
How your project works
- 1
Send photos, get a written quote
Send three photos of the space and a sentence about what you want. You get a clear, itemized quote within one business day. We only come out to measure first when the job needs a tape measure — no pressure, no games.
- 2
Pick materials, or bring your own
We help you choose profiles and materials that fit the house and the budget, or match your existing millwork exactly — or you buy the door or trim yourself and we install it. Everything is confirmed before the crew is scheduled.
- 3
Clean, precise installation
The crew shows up on time, protects floors and furniture, and installs with tight joints and consistent reveals. Photos of the finished work go in your job folder.
- 4
Walkthrough and invoice
We walk the finished work with you. If anything is not right, we fix it before we call the job done. Then one invoice, paid by check or direct deposit — no card fees, no payment links.
Situations and options
Adjustable aluminum threshold
The standard on steel and fiberglass entry doors. An aluminum base with a cap that raises or lowers on screws to meet the sweep. Cut to length between the jambs, bedded in sealant, and set so the door closes with an even line of contact.
Wood sill replacement
Older wood doors sit on a solid oak sill that slopes to the outside. When it is worn through or rotted, we cut a new sill from oak or a composite to the same profile, set it on a sill pan, and fit the door sweep to it.
Threshold cap only
When the aluminum base is sound and only the cap is cracked or the vinyl insert is gone, a replacement cap or insert is a quick swap. We check the base for looseness and water first, so you are not buying a cap for a threshold that needs to come out.
Threshold plus jamb splice
Thresholds and jamb bottoms rot together because the same water hits both. When the jamb legs are soft where they meet the threshold, we splice them with PVC in the same visit and set the sill pan up the jambs as one repair.
Exterior Door Threshold Replacement — Replace a Rotted Door Sill: questions, answered
Can you replace just the threshold without replacing the door?
Yes. The threshold sits between the jamb legs and is fastened to the subfloor; it comes out on its own. We pull it, check and repair the subfloor if it is soft, set a sill pan, fit the new threshold and adjust it to the sweep. The door and the rest of the frame stay. If the jamb bottoms are also rotted, they get spliced at the same time, and that is still not a door replacement.
Why does my door threshold rock or feel spongy?
Either the screws holding it have lost their grip, or the subfloor underneath has rotted from water that got past the threshold over the years. A loose threshold on solid subfloor is re-fastened and re-bedded. A spongy one usually means the subfloor corner has to be cut out and patched before the new threshold goes in, and a sill pan added so it does not happen again.
What is an adjustable threshold and do I need one?
An adjustable threshold has a cap that raises or lowers on screws hidden under small plugs, so it can be set to meet the door sweep exactly. Nearly all steel and fiberglass entry doors use one. It is the right replacement for any door with a slide-on sweep, because the sweep and the cap seal against each other and the adjustment takes up wear. Older wood doors with a solid oak sill are usually replaced like for like.
Does a new threshold fix cold air under the door?
Often, yes, when the old threshold was cracked, sunken or set too low for the sweep. The new one is adjusted up to the sweep until the door closes with a slight drag across its full width. If the door has sagged on its hinges, the gap is a wedge and the threshold alone will not close it; the door gets re-hung first. We check that before setting the threshold.
What is a sill pan and why add one?
A sill pan is a shallow tray, plastic or formed metal, that sits under the threshold with dams at each end turned up the jambs. Water that gets past the threshold lands in the pan and drains out instead of soaking the subfloor and the jamb bottoms. Most thresholds that rot were installed without one. We add it on every threshold replacement.
How long does it take to replace a door sill?
About two to three hours for one door: pull the old threshold, clean to the subfloor, set the sill pan, fit and bed the new threshold, adjust it to the sweep. A subfloor patch or a jamb splice adds an hour or two. Two doors on the same house fit in a morning.
Get a written quote for this job
Three photos and a sentence is enough. You hear back within one business day. Or text the photos to 763-204-2099.
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Read morePage reviewed September 24, 2026 · JMB Builders LLC, MN license BC809005 · All doors pages
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