Exterior Door and Threshold Replacement

Purpose

An exterior door is a hole in the weather barrier that somebody walks through. Fitting the slab is the easy half and it is the half customers watch; the half that decides whether the shop comes back is the sill pan, the flashing laps and the drainage path, all of which are buried before the customer ever sees the door work. A door hung dead plumb with no pan under it rots the sub-sill from the inside and shows up two or three years later as a soft floor inside the threshold.

The other reason this exists is exposure. Once the old unit is out, the building is open. A tech who starts a door at four in the afternoon with rain coming has committed the shop to a night of somebody's house standing open.

Scope

Covers replacement of an exterior swinging door in an existing opening: pre-fit verification, removal, sub-sill repair within the opening, sill pan and flashing integration, setting a prehung unit or a standalone threshold, and the water and security verification before handover.

Does not cover reveal, strike and bind diagnosis on a door that is staying, which the interior door adjustment SOP owns and which reads the same on an exterior slab; siding removal beyond the opening trim, which the siding patch SOP owns; structural header work; or any opening whose framing is rotten past the trimmer studs. Sealant selection and tooling belongs to the caulking and sealant renewal SOP.

Roles and responsibilities

Procedure

1. Confirm the job can be closed today before you open anything. Check the forecast for the working window, confirm the replacement unit is on site and correct, and confirm you have material to secure the opening if the day goes wrong. Acceptance: unit on site with hand, size, jamb depth and swing matching the opening as measured, plus sheet goods and fasteners for a temporary closure. What wrong looks like: a wrong-hand prehung discovered after the old door is in the driveway. Stop rule: any of those missing stops the visit before demolition, and the door stays in service. Hazard: this is a desk-level decision made at the door, no physical hazard, but it is also the gate on the pre-1978 paint check below, so do not skip it as paperwork.

2. Check the opening for paint age and for water damage before the first fastener comes out. In housing built before 1978, treat painted trim and jamb surfaces as lead-bearing unless tested by a certified renovator. Acceptance: for target housing built before 1978, either a documented negative test or the work run under the EPA Renovation, Repair and Painting rule at 40 CFR Part 745 Subpart E by a certified renovator with contained work practices; the exterior de minimis in that rule is 20 square feet, and removing or demolishing painted components is outside the exemption whatever the area, which is what a door replacement does. What wrong looks like: pulling painted casing dry on a 1950s house and sweeping the chips into the flower bed. Stop rule: pre-1978 paint plus no certified renovator on the crew stops the job at scheduling, not at the door. Hazard: lead reaches people by inhalation of dust and by hand to mouth, so the controls are wet methods, plastic sheeting to catch debris, no dry sanding or power removal, HEPA cleanup, and no eating, drinking or smoking on site until hands and face are washed.

3. Remove the old unit and control the opening from the moment it is open. Cut the sealant lines, pull casing and trim, cut fasteners, and take the unit out in one piece where you can. Acceptance: the opening is clear, and from that minute forward it is either being worked on or closed. What wrong looks like: an open doorway left while the tech goes to the supply house. Stop rule: work stops and the opening gets a fastened temporary closure any time the tech leaves the immediate area or the weather turns. Hazard: an exterior door is heavy and often glazed, so it is a two-person lift or a dolly, gloves on, glass taped before it moves, and nobody stands downhill of it; a reciprocating saw run blind through a jamb finds doorbell, thermostat and alarm wiring, so cut on the exposed side, keep depth short, and treat any conductor found as live until proven otherwise.

4. Read the sub-sill and repair it before anything covers it up. Probe the sub-sill, the trimmer bottoms and the sheathing at the corners with an awl, and take moisture readings at the same points. Acceptance: an awl at hand pressure penetrates no more than about 1/8 inch into the sub-sill and the trimmer bottoms after cleaning, and any replaced framing bears the same as what it replaced. What wrong looks like: dropping a pan over dark, damp framing because the pan will keep water off it, which it will not, since the framing is already wet from inside. Stop rule: rot extending past the trimmer studs or into the rim below stops the step and goes to the lead as structural. Hazard: this step has your hands and knees on the opening edge at floor level with a drop outside, so clear the landing, set a fall guard or a rail where the door is above a stoop, and never work the sill from a ladder leaned into the opening.

5. Install the pan and lap the flashing so water leaves the wall. Fit a sill pan with end dams and a back dam, set it on a continuous bed of sealant, then integrate jamb flashing over the pan flanges and head flashing over the unit and under the water-resistive barrier above, so every lap sheds downward and outward. Acceptance: pan continuous with sealed corners, back dam present, jamb flashing lapping over the pan, head flashing tucked under the barrier above, and no reverse lap anywhere on the assembly; the IRC sets exterior wall flashing requirements at Section R703 in the edition your jurisdiction has adopted. What wrong looks like: a pan sealed at all four sides, which turns a drainage tray into a bathtub. Stop rule: if the wall barrier above the head cannot be lifted to receive the head flashing, stop and call the lead rather than face-taping over it. Hazard: flashing primers and sealants carry solvent vapor and skin hazards, so work upwind, follow the product label for ventilation and gloves, and keep the primer off the pan bedding surface it is not made for.

6. Set the unit to level, plumb and square, and fasten into framing. Shim and fasten at each hinge and at the strike with screws long enough to reach the trimmer, checking the sill for level and the hinge jamb for plumb as you go. Acceptance: sill level within about 1/16 inch across the opening, hinge jamb plumb within about 1/8 inch over its height, the unit square with equal head and side gaps, and the door holding position anywhere in its swing. What wrong looks like: drawing the jamb in with fasteners to fix a gap, which bows the jamb and puts the weatherstrip out of contact along its length. Stop rule: an opening that will not take the unit square after a second shim pass is out beyond what setting a unit will correct, so stop and price the opening correction. Hazard: a prehung unit tips out of the opening while it is unfastened, so brace it from inside before letting go, and keep fingers off the hinge edge and out of the gap while it is being tried.

7. Put the envelope back and prove it, on water and on the lock. Reinstall trim, seal the perimeter, then run a low-pressure hose over the assembly for at least five minutes, working bottom to top, while a second person watches the inside of the opening. Acceptance: no water inside at the sill, the jambs or the head at the end of the run; every weatherstrip in contact around the perimeter with the door closed, checked by dragging a strip of paper and feeling drag all the way round; and the deadbolt throwing fully into a strike fastened into the trimmer with long screws, not into the jamb alone. What wrong looks like: a test run top to bottom, which wets everything at once and tells you nothing about where it came in. Stop rule: any water inside sends the assembly back to step 5 for the specific lap that failed, once; a second failure goes to the lead, and the door is not signed off as weathertight. Hazard: the test puts water on a walking surface next to an open doorway and, on many entries, near an exterior receptacle or light, so confirm the exterior circuit is GFCI-protected before wetting anything near it, keep cords and the hose out of the swing path, and dry the interior floor before anyone walks it.

The record this produces

The unit specification as fitted, the pre-1978 paint determination and who made it, sub-sill probe depths and moisture readings before repair, what framing was replaced, the pan and flashing sequence photographed before trim goes on, the sill level and jamb plumb as set, and the water test result with its duration and who watched inside.

The photograph of the pan and laps is the single most valuable line here, because it is the only evidence that exists once the trim is on. The office reads the paint determination when a lead question arrives. The next tech reads the sub-sill readings to know whether a damp floor inside the threshold is new or is the same water nobody stopped.

Worked pass: 36 by 80 inch entry door, threshold rotted, 1994 house

Step 1: unit on site, right-hand inswing confirmed against the opening, jamb depth matching, forecast dry until evening.

Step 2: house built 1994, so outside the pre-1978 rule; recorded as such rather than left blank.

Step 3: old unit out in one piece, two-person lift, glass taped. Opening open from 9:40 to close of work with the tech present throughout.

Step 4 FAILED. The sub-sill took the awl 3/8 inch at hand pressure across the middle 20 inches and read 26 percent, against an acceptance of no more than about 1/8 inch. The stop rule was checked first: probing at the trimmer bottoms went in under 1/8 inch and the rim below read 12 percent, so the rot had not reached the trimmers and it stayed with the tech rather than going to the lead. The sub-sill section was cut out and replaced with treated stock bearing on the same framing, and the replacement re-probed under 1/8 inch before anything covered it.

Step 5: pan set with end dams and back dam on a continuous sealant bed, corners sealed, front edge left open to drain. Jamb flashing lapped over the pan flanges, head flashing tucked under the lifted barrier above. Photographed before trim.

Step 6: sill level read 1/16 inch across the 36 inch opening, hinge jamb plumb 1/16 inch over its height, head and side gaps equal within 1/32 inch, door held position through its swing.

Step 7: hose run 6 minutes bottom to top with the customer watching inside. No water at sill, jambs or head. Paper drag felt continuous around the full perimeter. Deadbolt threw fully into a strike screwed into the trimmer with 3 inch screws. Exterior receptacle beside the door confirmed GFCI-protected before the hose came out.

References

• 40 CFR Part 745, Subpart E, the EPA Renovation, Repair and Painting rule, for pre-1978 target housing, its exterior de minimis area and the certified renovator requirement
• International Residential Code Section R703, in the edition your jurisdiction has adopted, for exterior wall flashing and water-resistive barrier requirements
• The door and pan manufacturers' installation instructions, which own the fastener schedule, the shim locations and the pan bedding requirement that the warranty depends on
• See related: Interior Door Adjustment and Replacement; Caulking and Sealant Renewal Visit; Siding and Trim Patch Repair