Door installation is mostly about the opening, not the door. A new unit only hangs square if the rough opening is square, the sill plate under it is sound and the floor below is level. So the old unit, its interior casing and its exterior brick molding come out first, and the wall frame and sill plate are inspected for water, insect and other damage before anything new goes in. Threshold flashing is set and sealed, framing gaps are insulated, and casing, brick molding, lockset and paint finish the job.
What door installation involves, from removal to final paint
The sequence below is what our contracts actually say, in the order the work happens. It is the same shape whether the unit is an interior passage door or a double patio door.
- Protect the house. Floor and furniture protection goes down, with drop cloths over flooring, furniture and electronics, and plastic tenting where the work will raise dust.
- Remove the old unit. The door unit, interior casing and exterior brick molding come out, and on a full replacement the frame and sill come with them. The old door is hauled away and disposed of.
- Inspect the wall frame and sill plate. Every opening we open gets checked for water, insect and other damage, and you are told what is found before the new unit goes in.
- Install threshold flashing. On exterior openings, new metal threshold flashing goes in before the unit and is sealed with polyurethane caulk to stop future decay of the jamb and house framing. Where the head is exposed, top-rail flashing goes on too.
- Set and fasten the new unit. The door is shimmed, leveled and secured so the reveal is even and the slab closes against the stop along its whole height.
- Insulate and seal the gaps. The gap between the jamb and the rough framing is filled with fiberglass insulation or expanding foam, never left open.
- Trim it out. New interior casing to match the existing, rot-resistant composite brick molding outside, and the end grain of the new jamb sealed against decay.
- Hardware and finish. Lockset and deadbolt fitted, everything caulked and sealed inside and out, nail holes filled, then primed and painted to match.
Prehung door units vs. door slabs: which one your opening needs
The single biggest decision on a door installation is whether you are buying a door or a door and a frame.
- A prehung unit
- The slab arrives already hung in its own jamb with the hinges mortised and the strike bored. This is what we fit on almost all exterior work — primed white prehung inswing units, six-panel steel doors, full-lite glass patio doors — because the new jamb is square even when the old one was not.
- A slab into an existing frame
- Cheaper and faster, and reasonable when the existing frame is genuinely sound and square. We do this on interior doors regularly: individual passage door slabs replaced, with the casing, baseboard and corner molding made good around them.
- A new frame taking an existing slab
- Less common but real. On a commercial entry where the lower two to four feet of the frame was damaged, we installed a new 36 by 84 inch solid 20-minute fire-rated frame and reinstalled the existing exterior slab into it, with double-key deadbolts fitted.
- An owner-supplied door
- We install doors homeowners have already bought, including special orders picked out at a big-box store and owner-provided sliding closet doors. The only thing we ask is that the size and swing are confirmed before it is ordered.
Installing a door in an out-of-square or settled opening
Older houses move. The opening that took a door in 1978 is rarely still square, and a prehung unit forced into a racked opening will bind within the year. What we do about it:
- Level the floor below the door. On entry doors where the floor under the opening was out of level, leveling that floor was written into the scope before the new unit was set. This is the step most often skipped elsewhere and the reason a new door starts dragging.
- Resize the opening to the unit. Where a replacement would not fit as-is, we have resized openings with 2x4 framing, then made good the exterior trim and the drywall inside.
- Reframe to a standard size. On a living room opening that had been cut oversized and was failing, the outside of the opening was framed back with 2x4s to a 6 ft wide opening at the existing height, with pressure-treated sill pieces, and the new wall was clad in matching HardiePlank siding and trim.
- Shim, don't force. The unit is set plumb and level to itself, and the difference between the unit and the opening is taken up in shims and insulation rather than in the door.
- Deal with the rot first. Where the sill plate or jamb stock is soft, that gets cut out and replaced before the new unit lands on it — see rotted wood and trim repair.
Cutting a new door opening: framing, headers and rough openings
Putting a door where there was never a door is a framing job with a door at the end of it. We do this work regularly as part of remodels and conversions.
- Interior openings. We have extended framing to create a new 36 inch door opening in a lower-level entryway, and cut a new door through from a bathroom into a master bedroom during a remodel. Existing entry doors have been resized and relocated where a layout changed.
- Structural openings. Where a load-bearing wall is involved, temporary shoring walls go up before anything is removed, and the opening is framed with posts and headers per engineering plans. That is not handyman work and we do not treat it as such.
- Exterior openings. A crawl space with no direct exterior access had a new door opening cut and framed as part of an encapsulation job, with the surrounding grade corrected at the same time.
- Openings in the ceiling. Pull-down attic stairs are the same problem turned upward: a 22 by 31 inch opening cut between the trusses, 2x6 pine framing installed and braced to the trusses, then the unit set and secured.
- Making good afterwards. New drywall, casing, baseboard and paint are part of the scope, not a second visit — see interior and exterior painting.
Converting a window or a wall into a door opening
Window-to-door conversions are some of the most satisfying work we do, and they are unforgiving if the opening is not prepared properly.
On a kitchen remodel the homeowner wanted a window turned into a French patio door: the window opening was reframed down to the floor to accept a full-height door, and the siding was matched with HardiePlank around the new opening. On another house, a picture window became a patio door — the glass panel and frame came out, the ten-inch knee wall beneath it and the surrounding trim were removed, the opening was prepared and the framing secured, threshold flashing was installed and caulked with polyurethane against jamb and framing rot, and a 72 by 80 inch French patio door was set in.
Garage conversions run the same way. On an attached garage turned into a bedroom, the garage door opening was framed for a new six-foot double French door and the old side entry opening was framed down to a window opening. If you are weighing a window change against a door, window repair and replacement covers the other half of that decision.
Interior door installation: pocket, bifold and closet doors
- Pocket doors
- We install pocket doors in place of swing doors where space is tight — most often during kitchen and basement work, where a closet door was replaced with a pocket door as part of the wider scope. See pocket and barn door repair for servicing them afterwards.
- Bifold doors
- New bifolds are resized to fit the existing opening rather than the opening being rebuilt around a stock size, then the door, track and brackets are installed and the slab is prepared and painted to match. We have also converted bifold openings to a swing door where the bifold was never the right answer.
- Sliding and louvered closet doors
- Fitted into existing closet openings, including doors the homeowner supplied, and adjusted until they run and latch properly. We have widened closet openings as part of larger jobs where the existing opening was too narrow.
- Passage and utility doors
- Interior slabs, laundry and mechanical room doors, and basement doors go in with new casing to match the existing trim, then caulked, primed and painted.
- Fire-rated assemblies
- Where code calls for it — a commercial entry, a hallway opening off it — we install 20-minute fire-rated solid doors and frames, with swing direction confirmed against approval before ordering.
Exterior door installation: flashing, insulation and sealing
Everything that goes wrong with an exterior door five years after it was installed traces back to three details that cost almost nothing to get right on the day.
- Threshold flashing, installed before the unit. New metal threshold flashing goes in first and is sealed with polyurethane caulk. Without it the sill plate and the jamb feet sit in whatever water gets past the threshold, and we have pulled doors where that had been happening for years.
- Framing gaps filled, not left hollow. Fiberglass insulation or expanding foam fills the gap between jamb and framing. An uninsulated gap is a draft, a cold floor and a path for water.
- Jamb end grain sealed. The cut ends of a new jamb wick water faster than any other part of it, so they are sealed before the trim goes on.
- Composite brick molding instead of wood. We specify rot-resistant composite around exterior openings as standard, because wood brick molding in the same position is what we keep coming back to replace.
- Top-rail flashing where the head is exposed. On more than one leak call the cause was flashing that had never been installed above the door head trim, so it goes on as part of the install rather than after the ceiling stains.
For entry doors specifically, front door repair and replacement goes into security, sidelights and threshold detail.
Do you need a permit for door installation in Virginia?
Swapping a door into an existing opening of the same size generally does not require a permit. Cutting a new opening, changing the size of an opening, or touching a load-bearing wall does, in every jurisdiction we work in.
Where a permit applies we pull and process it ourselves, and the permit and processing fees are written into the contract rather than turning up later. On projects built to approved plans, the plans, permits and inspections are carried in the contract price, work is staged against inspection milestones, and nothing is closed up before the inspector has seen it. All of it is performed according to the Virginia building code by a licensed contractor holding Virginia DPOR license #2705070610.
How door installation is scheduled and priced
Most door installations start when the door arrives, not when the contract is signed. Our scopes say so plainly — work begins upon door delivery — because a special-order unit sets the calendar and we would rather tell you that up front than open a wall and wait. Where an existing door has to keep working until the new one lands, we write that in too.
We do not quote door prices by phone and we do not publish them. The unit is only part of it: an opening that has to be reframed, a sill plate that has rotted, a floor that has to be leveled, siding that has to be matched, and interior finishing all change the job. An estimator comes to the property, measures the opening, and gives you a written price before any work begins. If what you have is a door that binds rather than a door that needs replacing, start at door repair. We cover Northern Virginia and Washington DC on (703) 256-8080.
