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Safety Cue
Task-specific safety guidance for ordinary work hazards.
Project 16
Install Stair Skirt Boards
Scribe, cut, fit, and install one finish stair skirt board against the existing tread-and-riser profile without altering structural stair geometry, rise, run, tread depth, or nosing.
Field Cue System
These cues appear at the point of work. Stair work carries fall and trip hazards in addition to ordinary finish-carpentry hazards, so the safety and code cues in this chapter are followed exactly as written.
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Critical Safety Cue
Serious injury, fire, or major damage is possible.
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Field Safety Cue
Practical work-area safety: lighting, cords, footing, and housekeeping.
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Code Alert
Local requirements vary. Verify permit, inspection, and jurisdictional rules.
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Manufacturer Cue
Follow product-specific instructions for tools, materials, and equipment.
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Measurement Cue
Clearance, layout, spacing, and reference-point guidance.
Job Overview
This project qualifies you to scribe, cut, fit, and install one finish stair skirt board against an existing stair without changing the stair's structural geometry. The finished work product is a securely installed skirt board that follows the tread-and-riser profile of the stair, terminates correctly at the top and bottom of the run, and preserves the accepted rise, run, tread depth, nosing, landing, guard, and handrail conditions established before this project begins.
You will confirm that the stair has already passed structural inspection, inspect the wall and stair surfaces the skirt will contact, scribe the skirt blank directly against the treads and risers, cut the scribed profile with the approved saws and hand tools, test-fit the skirt without forcing it, fasten it to framing or approved backing, and inspect the finished stair-wall transition for gaps, security, and safety.
This project follows Project 15, which completed closet trim and shelving cleats, and precedes Project 17, which installs finish trim directly on the treads, risers, and nosings. The skirt board installed here establishes the wall-side reference that Project 17's tread and riser trim will fit against.
Skills You Will Demonstrate
- FC-091 — Measure the stair profile, including every tread, riser, nosing, and landing transition the skirt board must follow.
- FC-092 — Scribe the skirt board directly against the existing stair and wall to capture the exact tread-riser-nosing profile.
- FC-093 — Cut the skirt board to the scribed line using the approved saws and hand tools without altering stair geometry.
- FC-094 — Fit the skirt board to the treads and risers, correcting minor contact points without forcing the piece.
- FC-095 — Fasten the skirt board to framing or approved backing while keeping fasteners clear of nosings and concealed services.
- FC-096 — Inspect the finished stair-wall transition for gaps, rocking, unsafe projections, and fastener security.
Where This Skill Fits
Every stair-trim project in this book depends on the stair having already passed a structural readiness decision before finish work begins. This project does not create or verify that structural acceptance; it uses the previously accepted rise, run, tread depth, nosing, landing, guard, and handrail conditions as the fixed geometry the skirt board must follow.
The skirt board installed here becomes the wall-side reference for Project 17, which installs tread, riser, and nosing trim. Any scribe error, forced fit, or altered geometry introduced in this project will surface as a fit or safety problem in Project 17.
Scope and Intended Use
This project covers:
- reviewing the approved stair geometry, finish profile, skirt thickness, wall condition, tread and riser status, and code constraints before starting
- confirming that rise, run, tread depth, nosing, landings, guards, and handrails have already been accepted through the responsible structural inspection
- barricading or otherwise controlling stair use during the work
- inspecting the wall, treads, risers, stringer, and floor transitions the skirt board will contact
- establishing the top and bottom skirt termination details from the approved finish specification
- selecting and acclimating a straight skirt blank
- scribing the blank against the stair and wall, labeling cut lines, and cutting to the scribed profile
- test-fitting, refining contact points, and installing the skirt board without changing tread width, nosing projection, or walking clearances
- fastening the skirt board to framing or approved backing and inspecting the finished stair-wall transition
This project does not authorize the learner to:
- correct a noncompliant or structurally defective stair using finish trim; a stair that has not passed structural inspection is referred to the responsible trade or a qualified stair specialist before this project begins
- alter rise, run, tread depth, nosing, landing, guard, or handrail geometry under this finish-trim chapter
- leave the stair in unrestricted service with loose nosing, protruding fasteners, or a partially secured skirt board at any point during the work
- fasten near electrical boxes, plumbing fixtures, service penetrations, or unlocated utility paths without first locating them
Any stair that has not received an approved structural readiness decision must be corrected by the responsible trade and reinspected before this project's skirt-board installation begins.
Reference Conventions
Establish these references before scribing or cutting, and do not change them mid-run.
| Term | Definition |
|---|---|
| Scribe line | The line transferred from the actual tread, riser, nosing, and landing profile onto the skirt blank, used to guide all cutting in this project |
| Waste side | The side of the scribe line that is removed during cutting; must be labeled on the blank before it leaves the stair |
| Top termination | The specified detail where the skirt board ends at the top of the stair run or landing |
| Bottom termination | The specified detail where the skirt board ends at the base of the stair run or floor transition |
| Contact point | Any location where the skirt board touches a tread, riser, nosing, or landing surface |
| Structural readiness decision | The prior, documented acceptance of stair rise, run, tread depth, nosing, landing, guard, and handrail geometry that this project relies on and does not repeat |
Stair Skirt Work Order Record
Before scribing, record the stair identity and controlling documents directly on the project worksheet:
Stair or run identifier: ______ Structural readiness reference: ______ Finish specification reference: ______
Date started: ____________ Installer name: ____________
Prerequisites
- An approved structural readiness decision on file for the stair, confirming rise, run, tread depth, nosing, landings, guards, and handrails have been accepted
- The approved stair geometry, finish profile, skirt thickness, wall condition report, and finish specification available for the stair being trimmed
- Completion of Project 1 through Project 15, including the room readiness inspection, workstation setup, and measuring and cutting fundamentals used throughout this book
- A skirt-board blank of the specified material, thickness, and length, acclimated according to the finish specification
- A means of barricading or controlling stair access, and an approved alternate route where the stair is the only access to occupied space
Common Field Fundamentals
A stair skirt board is a scribed finish piece. Its accuracy depends entirely on a careful transfer of the actual tread, riser, nosing, and landing profile onto the blank, not on the nominal dimensions in the stair schedule. Because the stair remains in partial or full use during this project, controlling access and preserving safe walking conditions at every stage of the work is as important as the fit of the finished piece.
GeometryRise, run, tread depth, nosing, landing already accepted and preserved throughout this project
ScribeTread, riser, nosing, and landing profile transferred directly onto the skirt blank
FitTest-fitted without forcing, with contact points refined rather than gaps filled
AccessStair barricaded or controlled throughout scribing, cutting, fitting, and fastening
Scribing Against an Existing Stair
Position the skirt blank against the stair and wall in its approximate final location, supported so it cannot shift. Set the compass or scribing tool to the widest gap between the blank and the stair profile, then run the tool along the full length of the treads, risers, nosings, and landing transitions, transferring the profile onto the blank in one continuous pass. Label the waste side immediately after scribing, before the blank is moved.
FC-091 – FC-096
Stair Finish Trim Qualification
Stair Skirt Board Installation
A. Finished-Project Specification
Quantity: one continuous scribed and installed skirt board per stair run specified in the finish specification, terminated at the approved top and bottom details.
B. Component Schedule
| Component | Quantity | Material | Finished Size | Preparation |
|---|---|---|---|---|
| Skirt board | 1 per run, or per approved scarf section | As specified in the finish specification | Length and width per approved stair geometry; scribed to actual tread-riser-nosing profile | Acclimated per finish specification; scribed, cut, and test-fitted before final fastening |
| Top termination piece or return | As specified | Matching skirt material | Per approved top termination detail | Cut and fitted to the specified termination style |
| Bottom termination piece or return | As specified | Matching skirt material | Per approved bottom termination detail | Cut and fitted to the specified termination style |
C. Material and Fastener Takeoff
- Skirt stock: one blank per run, or the number of sections specified for an approved scarf joint, in the material, thickness, and finish grade identified in the finish specification.
- Fasteners: the type, diameter, length, and spacing specified for the skirt material and the identified backing or framing.
- Adhesive: only where specified, in the product and coverage identified by the finish specification.
- No structural stair material: this project does not purchase or consume tread, riser, stringer, guard, or handrail stock; those are addressed by the responsible trade before this project begins.
D. Fastener and Backing Schedule
| Location | Fastener or Method | Spacing | Backing Requirement |
|---|---|---|---|
| Field of the skirt board | As specified in the finish specification | As specified in the finish specification | Framing or approved backing located before fastening |
| Top and bottom terminations | As specified for the termination detail | As specified | Framing or approved backing at the termination point |
| Locations near nosings | As specified, angled to remain clear of the nosing | As specified | Confirmed clear of nosing support and concealed services |
E. Acceptance Standards
| Check | Standard |
|---|---|
| Structural readiness | Approved structural readiness decision on file before scribing begins |
| Scribe accuracy | Skirt board follows the tread, riser, nosing, and landing profile with contact points refined by plane, rasp, file, or sanding block rather than filled |
| Geometry preservation | No change to tread width, nosing projection, rise, run, or walking clearance introduced by the skirt installation |
| Fastening security | Skirt board fastened to framing or approved backing per the fastener and backing schedule, with no proud or exposed fasteners in a walking surface |
| Termination fit | Top and bottom terminations match the specified detail without gapping or forcing |
| Stability | No rocking, unsafe projection, or loose section anywhere along the installed skirt board |
F. Document Review and Stair Confirmation
- Review the approved stair geometry, finish profile, skirt thickness, wall condition, tread and riser status, and code constraints. Confirm the documents correspond to the stair being trimmed.
- Confirm that rise, run, tread depth, nosing, landings, guards, and handrails have been accepted. Locate the structural readiness decision on file and record its reference on the work order.
- Do not use finish trim to correct noncompliant or structurally defective stairs. If no structural readiness decision is on file, or if the stair shows visible defects, stop and refer the stair to the responsible trade before continuing.
G. Access Control and Surface Inspection
- Barricade or control stair use during work. Post the barricade and establish an approved alternate route if the stair is the only access to occupied space.
- Inspect the wall, treads, risers, stringer, and floor transitions. Note surface condition, moisture, movement, or damage that could affect the skirt fit or fastening.
H. Layout and Blank Preparation
- Establish the top and bottom skirt termination details. Confirm the specified termination style against the finish specification before cutting begins.
- Select and acclimate a straight skirt blank. Confirm the blank meets the specified material, thickness, and length, and has acclimated according to the finish specification.
I. Scribing
- Position the blank against the stair and wall. Support it so it cannot shift during scribing.
- Scribe each tread, riser, nosing, and landing transition. Set the scribing tool to the widest gap and run it in one continuous pass along the full profile.
- Label all cut lines and waste areas. Mark the waste side immediately, before the blank is removed from the stair.
- Remove the blank and verify the scribe sequence. Confirm every tread, riser, nosing, and landing transition is represented on the scribe line before cutting.
J. Cutting and Fitting
- Make straight, angled, and curved cuts using the approved saws and jigsaw. Follow the waste side of the scribe line throughout.
- Stay outside the final line and refine with plane, rasp, file, or sanding block. Remove material gradually rather than cutting directly to the line.
- Test-fit the skirt without forcing it. Position the cut piece against the stair and wall and check contact along the full profile.
- Refine contact points while preserving the full profile. Continue removing small amounts of material only at points where contact is incomplete.
- Confirm that the skirt does not change tread width, nosing, or walking clearances. Verify with the tape measure at representative points along the run.
K. Fastening and Final Inspection
- Apply adhesive only where specified. Use the product and coverage identified in the finish specification.
- Fasten to framing or approved backing. Follow the fastener and backing schedule for the field, terminations, and locations near nosings.
- Keep fasteners clear of stair nosings and concealed services. Angle or relocate fasteners as needed to avoid these locations.
- Inspect the stair-wall transition, top and bottom terminations, gaps, and fastener security. Check the full length of the installed skirt board against the Acceptance Standards table.
- Correct rocking, unsafe projections, and loose sections. Refasten, add backing, or replace the affected section as required.
- Keep the stair barricaded until the installation is secure. Remove the barricade only after the final inspection confirms a secure, safe installation.
Common Cutting Inspection
Apply the following checks to every cut made on the skirt blank, in addition to the general cutting standards established in Project 3.
- Waste-side check: confirm the cut removed material from the labeled waste side of the scribe line, not the finish side.
- Contact check: confirm the cut skirt board contacts every tread, riser, nosing, and landing transition along its length without a forced fit.
- Geometry check: confirm tread width, nosing projection, and walking clearance are unchanged from the accepted structural readiness decision.
- Termination check: confirm the top and bottom terminations match the specified detail.
- Fastener check: confirm every fastener is set into framing or approved backing, clear of nosings and concealed services, and not proud of the surface.
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Failure Points and Troubleshooting
Cleanup
This project ends with a secure, inspected skirt-board installation and a documented work record, not with removal of the finished piece.
- Remove offcuts, scribe waste, and sawdust from the stair and landing before restoring access
- Return saws, hand tools, clamps, and the stud finder to storage in working condition
- Confirm every fastener is set and no tools or fasteners remain on a tread, riser, or landing
- Store the compass or scribing tool setting notes with the project record for reference during Project 17
- Remove the barricade only after the final inspection in Section K confirms a secure installation
- File the completed work order, fastener and backing schedule, and inspection results with the stair project record
Field Terms
- Skirt Board
- The finish board installed along the wall side of a stair, following the tread-riser-nosing profile.
- Scribe Line
- The line transferred from the actual stair profile onto the skirt blank, used to guide cutting.
- Waste Side
- The side of the scribe line removed during cutting, labeled before the blank leaves the stair.
- Top Termination
- The specified detail where the skirt board ends at the top of the run or landing.
- Bottom Termination
- The specified detail where the skirt board ends at the base of the run or floor transition.
- Contact Point
- Any location where the skirt board touches a tread, riser, nosing, or landing surface.
- Structural Readiness Decision
- The prior, documented acceptance of stair geometry this project relies on and does not repeat.
- Nosing
- The projecting front edge of a tread, whose projection must not be altered by the skirt installation.
- Stop-Work Condition
- A documented hazard, defect, or missing structural acceptance that halts skirt-board work until corrected.
Skill Check
- Why must a stair have an approved structural readiness decision on file before this project's scribing begins?
- What is the correct method for transferring the tread-riser-nosing profile onto a skirt blank, and why must it be done in one continuous pass?
- Why must the waste side of the scribe line be labeled before the blank is removed from the stair?
- What corrective tools are used to refine a contact point on a test-fitted skirt board, and why is filling a gap not an acceptable substitute?
- Why must fasteners near nosings be angled or relocated rather than driven straight in at the nearest convenient point?
- What four geometry conditions must remain unchanged by the skirt-board installation?
- Why must the stair remain barricaded or controlled throughout scribing, cutting, fitting, and fastening?
- What must happen if the stair shows a defect or lacks a structural readiness decision when this project begins?
- Why does this project rely on the structural readiness decision from an earlier inspection instead of reinspecting rise, run, and tread depth itself?
- What must be verified before the barricade is removed at the end of this project?
Competency Rubric
| Competency | Independent Pass Standard | Not Demonstrated | With Assistance | Independently |
|---|---|---|---|---|
| FC-091 | Measures every tread, riser, nosing, and landing transition along the run and records the results accurately | |||
| FC-092 | Scribes the skirt board to capture the exact tread-riser-nosing profile in one continuous, correctly labeled pass | |||
| FC-093 | Cuts the skirt board to the scribed line using the approved saws and hand tools without altering stair geometry | |||
| FC-094 | Fits the skirt board to the treads and risers, correcting contact points without forcing the piece or filling gaps | |||
| FC-095 | Fastens the skirt board to framing or approved backing per the fastener schedule, clear of nosings and concealed services | |||
| FC-096 | Inspects the finished stair-wall transition and confirms no gaps, rocking, unsafe projections, or fastener defects remain |
Mark one column per competency. Only Demonstrated Independently awards the competency; Demonstrated with Assistance authorizes additional supervised practice but does not complete the requirement.
Inspection Checklist — Stair Skirt Readiness Worksheet
| Item | Inspected (Y/N) | Defect Found (Y/N) | Deficiency Recorded (Y/N) | Reinspected (Y/N) | Correction |
|---|---|---|---|---|---|
| Structural readiness decision on file | |||||
| Stair barricaded before work began | |||||
| Wall, tread, and riser surfaces inspected | |||||
| Skirt blank scribed in one continuous pass | |||||
| Waste side labeled before removal | |||||
| Test fit contact along full profile | |||||
| Tread width and nosing unchanged | |||||
| Fasteners into framing or approved backing | |||||
| Fasteners clear of nosings and services | |||||
| Top and bottom terminations fitted |
Total open deficiencies: ____________ Total closed deficiencies: ____________
Readiness decision: ______ (Approved / Conditional / Rejected) Date: ____________ Installer name: ____________
Performance Check
With the skirt board installed, review the installation against the Acceptance Standards table and confirm the structural readiness decision was on file before scribing, every tread, riser, nosing, and landing transition shows full contact without a forced fit, tread width and nosing projection are unchanged, every fastener is set into framing or approved backing clear of nosings and concealed services, and the top and bottom terminations match the specified detail. Complete the Stair Skirt Readiness Worksheet and remove the barricade only after every item is closed. If any item cannot be closed, record it as a condition, keep the stair barricaded, and identify the trade or professional responsible for correction before Project 17 begins.
Project Closeout
You have completed the sixteenth project in the interior finish carpentry sequence: installing stair skirt boards. This project required you to measure the stair profile at every tread, riser, nosing, and landing transition (FC-091), scribe the skirt board directly against the existing stair and wall (FC-092), cut the skirt board to the scribed line without altering stair geometry (FC-093), fit the skirt board to the treads and risers by refining contact points rather than forcing the piece (FC-094), fasten the skirt board to framing or approved backing while keeping fasteners clear of nosings and concealed services (FC-095), and inspect the finished stair-wall transition for gaps, rocking, unsafe projections, and fastener security (FC-096).
You now have a securely installed skirt board that follows the accepted stair geometry and establishes the wall-side reference for the tread, riser, and nosing trim installed next.
Keep the stair barricaded until the readiness decision is Approved, and store the completed work order and inspection records with the stair project file for reference through Project 17 and the Chapter 20 capstone.