Patio Door Replacement With New Deck Ledger Flashing
The floor inside the slider is soft and the deck board against the house is black.
Reply within one business day. Or call / text 763-250-3621.
Patio door replacement with new deck ledger flashing means the deck boards along the house come up, the old flashing over the ledger is replaced with new metal and tape tucked behind the housewrap, the door's sill pan laps over it, and the new door is set so water runs out, not into the rim joist. JMB Builders does it across the Twin Cities metro. Send photos and we reply within one business day, or book a free in-home estimate.
- Deck boards pulled along the house
- Ledger flashing replaced and tied to the sill pan
- Rotted ledger or rim repaired first
A deck ledger is the board bolted to the house that the deck joists hang from. It sits right under the patio door threshold, and the joint between the two is where water goes when either one leaks. Older decks were built with no flashing over the ledger or with a strip of aluminum that stops short of the door. Water from the door sill, from snow piled against the house and from the deck boards runs behind the ledger and into the rim joist and the subfloor under the door.
When the patio door is replaced, the ledger joint is open and reachable, and that is the time to flash it. The deck boards along the house come up for a couple of feet. The old flashing comes off. New flashing, a bent metal Z-flashing or a self-adhered membrane with a metal drip, goes over the top of the ledger and up behind the housewrap, then the door's sill pan laps over that so the two drain in order. If the ledger or the rim behind it is rotted, that is replaced first, with the deck supported.
Then the door goes in as usual: set plumb and square in the pan, foamed, sealed and trimmed, with the threshold sitting above the deck boards so meltwater drains away. The deck boards go back down. The ledger bolts are checked while it is open, since a ledger that has been wet for years may need new fasteners.
Get a written quote for this job
Three photos and a sentence is enough: a reply within one business day, or ask for a free in-home estimate. Or text the photos to 763-250-3621.
What you supply
- Photos of the patio door from inside with the floor in front of it, and from the deck showing the threshold and the board against the house
- A photo from under the deck of the ledger and rim, if you can get one
- The new door you want: slider or hinged, glass, color and hardware
- Paint color for interior trim, or leave it primed
What JMB supplies
- A measure of the opening and a look at the ledger, rim and subfloor from inside and from under the deck
- The patio door, ordered through ABC Supply to the opening
- Removal of the old door and of the deck boards along the house, and reinstallation of the boards
- New ledger flashing over the ledger and behind the housewrap, lapped under the door sill pan
- Repair of rotted rim joist, sill plate, subfloor or ledger, with the deck supported, quoted when we see it
- Sill pan, flashing tape, low-expansion foam, sealant and shims; door set with the threshold above the deck boards
- Exterior trim or capping and interior casing
- Photos of the flashing before the boards go back, and of the finished door, in your job folder
How it is priced: per door
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- How many deck boards come up and whether they can go back down or need replacing
- Rot in the rim joist, sill plate, subfloor or the ledger itself
- Deck boards that sit level with or above the threshold, which may need a board cut back or the door set higher
- The door itself: slider vs. hinged, size, glass and finish
- Siding type and how the exterior trim ties into the flashing
- A deck ledger that needs new bolts or a new board, which may need the city's building department involved
The under-deck photo matters most. If the rim is black or soft where the ledger meets it, the quote includes the repair; if it is dry, the flashing is a short extra line.
How long it takes
One patio door with new ledger flashing: one to two days on site, depending on rot. The door is ordered after the measure.
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 reply within one business day. Prefer a look in person? A free in-home estimate is always an option.
- 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
Flashing only, ledger sound
The deck boards come up, new flashing goes over the ledger and under the sill pan, the door goes in and the boards go back. Adds a few hours to the door job.
Rim and subfloor repaired
The rim joist and subfloor behind the ledger are cut back to sound wood and rebuilt before the flashing and the door go in, with the deck supported.
Ledger replaced
When the ledger itself is rotted, the deck is supported, the ledger is replaced and re-bolted, then flashed, and the door is set. The city's building department sets the rule on permits for deck structure; we check for your address.
Deck board cut back at the door
When the deck boards run level with the old threshold, the first board is cut back or dropped so the new threshold sits above the deck and drains.
Patio Door Replacement With New Deck Ledger Flashing: questions, answered
What is deck ledger flashing?
A strip of metal or membrane that covers the top of the ledger board and goes up behind the housewrap, so water running down the wall or off the door sill passes over the ledger and drips clear instead of running behind it into the rim joist. Without it the house framing behind the deck stays wet.
Do you have to remove deck boards to flash the ledger?
Yes, the boards along the house for a couple of feet out. The flashing has to go over the top of the ledger, and the boards cover it. Screwed boards come up and go back down; nailed or rotted boards are often replaced with matching stock.
What if the deck ledger is rotted?
It is replaced. The deck is supported on temporary posts, the old ledger comes off, the rim behind it is checked and repaired, a new ledger is bolted on, flashed, and the joists are rehung. It is a bigger job than flashing, and because it is deck structure, the city's building department sets the rule on a permit; we check for your address.
How does the door sill pan tie into the ledger flashing?
In order, like shingles. The ledger flashing goes on first, over the ledger and up behind the housewrap. The door's sill pan goes on next and laps over the top of the ledger flashing, so anything that gets under the door threshold runs out onto the ledger flashing and then off the front of the ledger.
Can ledger flashing be added to an older deck without replacing the door?
Yes, as a deck repair: the boards come up and flashing is fitted over the ledger and behind the siding above it. It is easier and more complete with the door out, because the sill pan and the flashing can be lapped together. If the door is going to be replaced in the next few years, do them together.
Does replacing the ledger flashing need a permit?
Flashing with the ledger left in place is usually treated as part of the door replacement. Replacing or re-bolting the ledger is structural deck work, and the city's building department sets the rule for that. We check what your city requires for the address and list the permit on the quote when one is needed.
Recent JMB work, from our job log
59 installs recorded across 30 Twin Cities communities since Dec 2025. Window and door installs for homeowners and the builders we work with. Counts come straight from our job log; no customer names.
Related jobs we do
Deck Door Replacement — Threshold to the Decking, Flashed to Ledger
The door onto the deck is where the house and the deck meet, and that joint is where water gets in. The new door is set so the deck boards, the threshold and the ledger flashing work together.
Read moreRotted Subfloor Under Patio Door — Floor, Rim and Sill Pan Repaired
The floor is soft in front of the sliding door, the flooring is buckled, or there is a stain on the basement rim below it. The door has been leaking into the floor.
Read moreSliding Patio Door Replacement — Door Supplied, Set in a Pan, Trimmed
The slider drags, the glass fogs, and the floor inside the sill is dark. You pick the new door; we order it to fit, fix what is under the old one and set it so it glides.
Read morePatio Door Replacement for a Walkout Rambler — The Main Floor Door
On a walkout rambler the main-floor slider sits a story up, over the basement patio. Same door, different job site: the deck is the stage and the rim joist under it is what the flashing protects.
Read moreDo I Need a Permit to Replace a Patio Door?
You do not want to guess, and you do not want a stop-work notice on the deck. The permit question has a short answer for your address, and we get it before the door is ordered.
Read moreLow Threshold Patio Door Replacement — Choosing a Low-Sill Unit
Someone in the house catches a toe on the patio door sill, or a walker or wheelchair has to bump over it. The replacement door can be ordered with a lower sill, and the install decides whether it stays dry.
Read morePage reviewed October 27, 2026 · JMB Builders LLC, MN license BC809005 · All doors pages
Where we work
Door Replacement & Installation near you
Based in Zimmerman, scheduling across the Twin Cities metro. Closest first: