Final Operation and Lock Verification Before Leaving the Job

Purpose

This is the gate between "the window is in" and "the window is done," and it exists because one cheap test catches most of what goes wrong. A sash lock that needs the sash lifted, pushed, or leaned on before the cam will throw is not stiff hardware. It is the frame telling you it is racked or bowed, and the lock is simply the first place the geometry error becomes visible to a finger.

The failure this prevents is the crew that treats that stiffness as a hardware problem, moves the keeper to meet the cam, and drives away with a unit that locks. The frame is still out of square. Over the next season the sash drops out of the balance range, the weatherstrip compresses unevenly, the seal takes a load it was not designed for, and the callback arrives as an air leak or a foggy unit with nobody able to connect it to install day.

Scope

Covers commissioning of each installed unit before the crew leaves the opening: fastening and shimming confirmation, square and straightness, operation, lock engagement, weep function, fall-prevention hardware, seal continuity, and the commissioned stamp. Applies to every replacement unit, insert or full frame.

Does not cover the egress area determination, which is made before the order ships and belongs to the egress window code verification SOP; this procedure only verifies that any opening control device fitted to an escape window still releases to the full opening. Does not cover the customer-facing demonstration and document handover, which is the next SOP in sequence.

Roles and responsibilities

The verification procedure

1. Confirm fastening and shimming are final before any operating test. Check the fastener locations and count against the unit's own installation instructions, and confirm a shim sits behind every fastener plus at the lock point and under the sill. Acceptance: fastener pattern matches the instruction sheet, no fastener driven through an unshimmed span. Wrong looks like a jamb screw pulled tight into a void, which draws the jamb inward and shows up two steps later as a binding sash. Stop rule: an unshimmed fastener is backed out, shimmed, and re-driven before the test sequence begins, because operation tested on non-final fastening tells you nothing. Hazard: a fastener driven hard beside a glazed unit can bow the jamb into the glass edge, so set the driver clutch low and seat the last turn by hand.

2. Measure square and jamb straightness against a stated tolerance. Measure both diagonals frame to frame, not trim to trim, and sight or string each jamb for bow. Acceptance: the tolerance printed in that unit's installation instructions, and where the sheet gives none, hold the diagonals equal within 1/8 in and each jamb straight within 1/16 in. Wrong looks like diagonals taken across the casing, which can read square on a frame that is not. Stop rule: out of tolerance means the shims move, not the hardware, and the unit does not advance until the diagonals close. Hazard: adjusting shims with the unit fastened puts a pry bar between frame and glass edge; back the fastener off first and work the shim, never lever against the glazing bead.

3. Operate the sash through full travel, one hand, in both directions. Run the operating sash from fully closed to its stop and back, twice, with a single hand and no shoulder. Acceptance: full travel with no binding or hard spot, and on a double hung the sash holds position anywhere in its travel with no creep. Wrong looks like a sash that runs easily for the first third and tightens near the top, which is a bowed jamb rather than a balance fault. Stop rule: any bind or any creep sends the unit back to step 2 before the hardware is touched. Hazard: a sash that drops unexpectedly will take fingertips at the meeting rail, so keep hands on the lift rail or the frame face and never inside the track while testing travel.

4. Throw the lock without touching the sash. With the sash fully closed and nothing holding it, rotate the cam or run the multipoint handle to its stop with one finger. Acceptance: the cam reaches its stop and the keeper engages with no lift, no push, and no lean, and the sash does not move as the lock draws. Wrong looks like a lock that only throws once someone lifts the sash a quarter inch. Stop rule: do not move the keeper. Go back to step 2 and prove the frame square first, then, on hardware whose instructions provide a keeper adjustment range, adjust only within that range. On a casement or tilt-and-turn, a small keeper adjustment is the manufacturer's intended method, so the rule is prove square first, not never adjust. Hazard: forcing a multipoint handle past a bind shears the gear drive inside the sash and turns a shim adjustment into a sash replacement.

5. Run a measured weep test on the sill. Pour about a pint of clean water into the sill track at the corner and watch the exterior weeps. Acceptance: set a shop standard and hold it; water beginning to exit within about 30 seconds and the track drained within about 2 minutes is a defensible default. Wrong looks like water standing in the track and nothing appearing outside, which is either a blocked weep or a sill back-pitched into the room. Stop rule: standing water is cleared and retested on the spot, and a sill that will not drain after the weeps are proven clear is a re-set, not a punch item. Hazard: water in a track on an upper floor runs to the interior floor and into the wall cavity, so put a towel on the interior sill and a bucket below before the pour, not after.

6. Verify any fall-prevention or opening control hardware, including its release. Where the IRC at Section R312 requires window fall prevention, which turns on an operable window whose sill sits less than 24 in above the finished floor with more than 72 in of drop to the exterior grade below, those being R312.2's figures in the edition your jurisdiction has adopted, the device complies with ASTM F2090 in the edition your jurisdiction has adopted. Acceptance: the device stops the opening before a 4 in sphere passes, releases without a key, tool or special knowledge, self-resets when the window closes, and on any unit designated as an escape opening still gives the full clear opening once released. Wrong looks like a device that limits the opening correctly and then will not release without two hands and a hunt for the catch. Stop rule: a device that does not release cleanly is replaced, never left with the customer as "you get used to it." Hazard: test the release standing beside the opening, not leaning into it, because the sash swings free the instant the stop clears.

7. Check seal and air-barrier continuity before the interior trim goes back. Inspect the exterior joint for a continuous tooled bead with backer rod in any deep joint, and confirm the interior perimeter is sealed with low-expansion foam or with backer and sealant. Acceptance: no skip at any corner, no visible daylight around the frame from inside with the trim off, and the foam labeled for window and door use. Wrong looks like fiberglass batt stuffed in the gap, which stops nothing moving air. Stop rule: any gap found after trim is on means the trim comes back off, on the spot. Hazard: standard high-expansion foam bows a jamb inward as it cures and jams a sash that passed step 3 an hour earlier, so only foam labeled low expansion for windows and doors goes in a window perimeter.

8. Stamp the unit and re-run any step the unit failed. Record each acceptance value against the unit line, then re-run any failed step and the operating test after it. Acceptance: every step has a recorded result, and every unit that failed a step carries both the failure and the re-test. Wrong looks like a clean sheet on a unit everyone remembers arguing about. Stop rule: an unstamped unit is not a finished unit, and the crew does not leave the address with one open unless it is written as a punch item with a date. Hazard: label and packaging debris left in a track blocks the weep you just proved, so the track is cleared and the weep visually re-checked as the last action on each unit.

The record this produces

The commissioning sheet carries, per unit: opening location, diagonal measurements and the tolerance used, jamb straightness result, operation pass with the balance-hold result on a double hung, lock result stated as throws freely or required a lift, weep test start and drain times, fall-prevention device model and release result where fitted, seal continuity pass, any step failed with what was found and what was changed, and the re-test result. It closes with the installer's name and the lead's re-check initials.

That sheet lands on the job record and gets read three times. The lead reads it the same day to pick which units to re-check. The coordinator reads it when a punch item is scheduled. Whoever takes the warranty call a year later reads it to answer one question fast: was this unit ever out of square, and what was done about it. A unit whose sheet shows a failed lock, a shim correction, and a passing re-test is a documented repair. The same unit with a blank sheet is an argument.

Worked pass: nine units, two failures

A whole-house job, nine units, three double hungs on the front elevation and six across the rear.

Unit 3 fails step 4. The sash closes cleanly and travels well, but the cam will not reach its stop unless the installer lifts the sash about a quarter inch. The stop rule is taken, the keeper is left alone, and the unit goes back to step 2, where the diagonals measure 5/16 in apart against the 1/8 in tolerance on the instruction sheet. The frame is racked. Backing off the lower fastener on the lock side reveals the cause: no shim behind it, so the screw pulled the jamb in as it seated.

The shim goes in, the fastener is re-driven with the clutch set low, and the diagonals come back to 1/16 in apart, inside tolerance and inside the earlier 5/16 in by a clear margin. Step 3 is re-run and the sash now holds anywhere in travel with no creep. Step 4 is re-run and the cam reaches its stop with one finger and no lift. Step 5 is re-run as well, because the frame geometry moved after the first pass, and the sill drains in about a minute and a half against the 2 minute standard.

Unit 7 fails step 5 on the first attempt with water standing after 2 minutes. A length of shim tape is sitting over the exterior weep slot from the install. It is pulled, the pour is repeated, and the track drains inside the standard. No fall-prevention device is required on this job, and step 6 is recorded as not applicable per unit rather than skipped.

Seven of the nine units passed every step on the first run. The two that did not were caught by a finger on a cam and a pint of water, and the unit 3 finding is the one to keep: the fastener that caused it was tight, the trim covered it, and every visual check on that opening would have passed.

References

1. The specific unit's manufacturer installation instructions, which set the fastener pattern, the shim locations, the square tolerance and any keeper adjustment range; where the sheet states a tolerance it governs over the default in step 2.
2. International Residential Code, Section R312, window fall protection provisions, in the edition adopted by your authority having jurisdiction.
3. ASTM F2090, standard specification for window fall prevention devices with emergency escape release mechanisms, in the edition referenced by that adopted code.
4. See related: the egress window code verification SOP, which determines whether an opening is an escape opening in the first place, and the customer walkthrough and warranty handover SOP, which demonstrates the release to the customer.