Build and Install Basic Stair Stringers

A. Finished-Project Specification

Scope: one complete stringer set for the stair opening and landing framed in Project 17, consisting of the approved number of stringers laid out from a single verified pattern, cut, installed on approved top and bottom bearing supports, and set at the approved spacing across the full stair width.

B. Component Schedule

Component	Quantity	Material	Finished Size	Preparation
Stair stringers	Per approved specification	Per approved specification	Per calculated rise/run and approved stringer depth	Laid out from verified pattern, cut, inside corners hand-finished
Top bearing support	Per approved detail	Per approved detail	Per approved detail	Installed at header before stringers are set
Bottom bearing support	Per approved detail	Per approved detail	Per approved detail	Installed at lower landing or floor before stringers are set
Temporary treads	Per approved sequence	Per project specification	Per stringer width	Installed only if the approved sequence permits temporary use before finish treads

C. Fastener and Hardware Schedule

Install top hangers, ledgers, bearing blocks, posts, and stringer-to-header or stringer-to-landing connectors exactly as specified in the approved stair and connector detail. Do not substitute fastener type, diameter, length, or spacing for a listed connector's required fasteners. Where the approved detail does not specify a value, obtain it from the design professional or manufacturer instructions before installing that connection.

D. Acceptance Standards

Check	Standard
Riser uniformity	Every riser height, including top and bottom risers, within the tolerance stated on the approved stair specification
Tread uniformity	Every tread run within the tolerance stated on the approved stair specification
Throat depth	Remaining stringer width at every notch meets or exceeds the minimum stated in the approved specification
Stringer matching	All matching stringers agree with the verified pattern within the tolerance stated on the approved specification
Top and bottom bearing	Full bearing contact at both ends, matching the approved connection detail
Headroom and landing clearance	Meets the minimum stated in the approved stair specification
Stringer spacing	Matches the approved specification across the full stair width, measured at top, middle, and bottom

E. Calculation (Steps 1–6)

1. Review the approved stair dimensions, total rise, available run, stair width, tread and riser requirements, landing elevations, headroom, stringer material, support, and connection details. Confirm the document revision against the project's document-control log.
2. Measure the actual finished-floor or framing elevation difference from the same reference surfaces used by the design. Record the field-measured total rise on the stair calculation record.
3. Determine the approved number of risers and uniform unit rise. Divide the field-measured total rise by the approved number of risers and record the result.
4. Determine the approved unit run and total stair run. Multiply the approved unit run by the number of treads and record the calculated total run.
5. Account for tread thickness, finished flooring, top connection, bottom bearing, and landing conditions. Adjust the top and bottom riser layout on the calculation record to reflect these conditions before marking any stock.
6. Record the complete stair calculation before marking material. Confirm every entry on the stair calculation record is complete and consistent with the approved specification.

F. Pattern Stringer Layout and Cutting (Steps 7–16)

1. Select straight, sound stringer stock of the specified size, grade, species, and treatment. Sight each piece for crown, bow, and twist using the straightedge before selection.
2. Reject stock with defects in the cut zones or conditions prohibited by the project specification. Set aside and label rejected stock; do not use it for the pattern or matching stringers.
3. Mark one pattern stringer using a framing square and approved stair gauges or layout method. Set the stair gauges to the calculated unit rise and unit run before marking the first line.
4. Mark the top plumb cut, tread and riser notches, bottom cut, and required landing adjustments. Mark every tread and riser line from the same gauge setting without readjusting the gauges mid-layout.
5. Verify remaining throat depth and all layout dimensions before cutting. Measure the throat depth at the narrowest notch and compare it with the minimum stated in the approved specification.
6. Cut the pattern stringer without overcutting inside corners. Stop each circular-saw cut at the marked inside-corner point.
7. Finish inside corners using the approved hand-tool method. Complete each inside corner with a handsaw or jigsaw so no overcut extends past the marked lines.
8. Test-fit the pattern stringer at the opening. Set the pattern stringer in position against the header and lower bearing surface without fastening it.
9. Verify top connection, bottom bearing, total rise, run, headroom, and landing relationship. Measure headroom from the nose line of each tread position to the framing above, and compare against the minimum in the approved specification.
10. Correct the pattern before tracing additional stringers. If a discrepancy is found, correct the pattern stringer or obtain design direction before proceeding to Section G.

G. Matching Stringers and Installation (Steps 17–23)

1. Trace and cut the required matching stringers from the approved pattern. Clamp the verified pattern to each piece of matching stock and trace every line before cutting.
2. Compare all stringers for matched rise, run, top, and bottom geometry. Lay all stringers together on a flat surface and check tread and riser line alignment across the set.
3. Install top hangers, ledgers, bearing blocks, posts, or other specified supports. Install these supports at the header and lower landing before setting any stringer.
4. Set and temporarily secure the outside stringers. Position the outside stringers at the approved stair-width dimension and temporarily fasten each end.
5. Install intermediate stringers at the approved spacing. Use the chalk line and tape measure to confirm spacing before permanently fastening any stringer.
6. Verify stringers remain parallel, aligned, fully supported, and consistently spaced. Check spacing at the top, middle, and bottom of the stringer set.
7. Install temporary or permanent treads only as permitted by the project sequence. Confirm the approved sequence before placing any tread material on the installed stringers.

H. Verification and Documentation (Steps 24–27)

1. Check every tread position for level and every riser position for uniformity. Record each measurement on the stair calculation record.
2. Verify total stair width, rise uniformity, run uniformity, headroom, landing clearance, support, and connector installation. Compare every result against the Acceptance Standards table in Section D.
3. Install required temporary guards and prohibit use until the stair has passed inspection. Confirm guards are in place at every open edge before leaving the installed stringer set unattended.
4. Record calculations, pattern dimensions, final measurements, connections, and inspection results. Complete every entry on the stair calculation record and attach it to the project's permanent documentation.