Undercut Door Jambs and Fit Flooring Around Trim

A. Finished-Project Specification

Quantity: one completed doorway undercut and flooring fit per assigned opening, with the jamb legs and casing cut flat to the height-gauge line, the doorway flooring piece measured and cut to fit beneath the trim, hidden expansion space preserved per the flooring manufacturer's specification, the approved transition installed where required, and the door confirmed operable through its full swing.

B. Doorway-Fit Schedule

Item	Target Condition	Verification Method
Height gauge	Built from the actual flooring and underlayment used in the room	Physical stack held against jamb
Concealed-service check	Wiring or plumbing near the cutting path identified and, if present, de-energized or protected before cutting	Non-contact voltage tester or approved verification method
Undercut	Jamb legs and casing cut flat and level to the marked line, with no structural, fire-rated, or weather-sealing component disturbed	Visual and physical inspection after cutting
Doorway flooring piece	Measured and cut to fit beneath the trim with correct orientation and pattern match	Direct measurement and dry-fit
Hidden expansion space	Gap beneath the trim preserved per the flooring manufacturer's specification	Direct measurement after the piece is set in place
Door operation	Door opens, closes, and latches without binding on the new flooring	Direct operation of the door through its full swing

C. Material Takeoff

• Height gauge scrap: one piece of the actual flooring and one piece of the actual underlayment per doorway, retained for reuse at additional doorways using the same flooring system.
• Doorway flooring piece: one matching piece per doorway, sized to the measured opening plus the required fitting allowance.
• Replacement casing stock: matching casing profile on hand in case an overcut or damaged section requires replacement.
• Transition material: the approved transition type identified in the Chapter 15 transition plan for this doorway, if required.

D. Acceptance Standards

Check	Standard
Cut height	Undercut registered directly from the flooring-and-underlayment gauge, flat and level along its full length
Trim condition	No structural, fire-rated, or weather-sealing component disturbed; no overcut into adjacent finish surfaces
Doorway piece fit	Flooring piece passes fully beneath the trim with correct pattern orientation and no visible gap at the cut line
Expansion space	Hidden expansion gap present and measured at or above the flooring manufacturer's minimum beneath the trim
Movement	Flooring not trapped, pinched, or fastened through the field beneath the trim where the flooring system requires free movement
Door operation	Door opens, closes, and latches through its full swing without binding, dragging, or rubbing on the new flooring
Documentation	Doorway record complete with gauge components, concealed-service check, and final inspection entries

E. Doorway Assessment and Height Gauging

1. Confirm flooring thickness, underlayment, adhesive, expansion, transition, and door-clearance requirements. Verify these against the flooring system installed or being installed on each side of the doorway before marking any cut line.
2. Inspect the door frame, casing, threshold, wall, and concealed-service risk. Note any fire-rated component, structural element, weather seal, or wall cavity that may contain wiring or plumbing near the cutting path.
3. Place a scrap of flooring and underlayment against the jamb as a height gauge. Hold the stack flat against the jamb leg at the location of the cut.
4. Mark the cut line. Trace the top of the gauge stack directly onto the jamb leg and casing using a pencil or marking knife.

F. Protection and Concealed-Service Verification

1. Protect the floor and adjacent trim. Cover the surrounding finished flooring and casing before cutting begins.
2. De-energize nearby circuits if the cutting path approaches concealed wiring. Check with a non-contact voltage tester and de-energize the affected circuit at the panel before proceeding if wiring is present or its location cannot be confirmed.

G. Undercutting the Jamb and Casing

1. Use an oscillating saw, jamb saw, or approved hand saw with controlled depth. Select the tool suited to the trim material and the doorway's access.
2. Keep the blade flat to the flooring gauge. Register the blade against the top of the gauge stack for the entire length of the cut.
3. Cut jamb legs and casing only as far as required. Limit the cut to the marked line and to the components specifically authorized for undercutting.
4. Do not cut structural door components, weather seals, fire-rated components, or thresholds without authorization. Stop and escalate if the cutting path would reach any of these components.
5. Remove waste material cleanly. Extract the cut sections without splintering the remaining jamb or casing above the cut line.
6. Vacuum dust and inspect the cavity. Use the HEPA vacuum and flashlight to confirm the cut is flat, level, and free of debris before fitting flooring.

H. Doorway Flooring Fit and Expansion

1. Measure the flooring piece passing beneath the trim. Take the dimension directly from the prepared opening, not from the general room layout.
2. Cut the plank, tile, sheet, or carpet edge for the doorway. Use the cutting tool matching the installed material and preserve pattern orientation.
3. Maintain hidden expansion space under the jamb. Cut the piece to leave the flooring manufacturer's specified gap beneath the trim once it is in place.
4. Slide or set the flooring beneath the trim. Fit the piece into the undercut opening without forcing it or damaging the cut edge.
5. Confirm the floor is not trapped or pinched. Check that the piece can move within its expansion allowance where the flooring system requires free movement, and is not fastened through the field beneath the trim.
6. Install the approved transition where required. Follow the transition type and clearance specified in the Chapter 15 transition plan for this doorway.

I. Operation Check and Final Inspection

1. Operate the door. Open, close, and latch the door through its full swing and confirm it does not bind, drag, or rub on the new flooring.
2. Inspect cut height, trim support, flooring movement, visible gaps, and transition fit. Confirm the undercut is flat and level, the trim above the cut remains fully supported, the flooring can move within its allowance, and no visible gap or misalignment is present at the cut line.
3. Correct overcuts using approved trim repair or replace damaged casing. Replace any casing section that was cut beyond the marked line or otherwise damaged during the undercut.
4. Document doorway treatment. Record the gauge components, concealed-service check, cut method, expansion measurement, transition type, and door-operation result on the doorway record.