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newSchoolWorks.com › VoTechWorks › Building & Construction › Carpentry › Stair Construction: Layout, Framing & Finishing › Lesson 8
BLD-CARP03-05 · Lesson 8 · 10.5 clock hours · lab

Landings and Platform Framing

Objective. Students will frame a stair landing platform to specified dimensions, confirm it is level and structurally attached to the wall framing, and verify that the resulting floor-to-landing and landing-to-floor rise values keep all risers equal.

Why Landings Matter

A stair landing is a platform built partway up a stair run that lets the stair change direction, provides a rest point, or satisfies code requirements for long runs. In an L-shaped or U-shaped stair, the landing becomes the structural floor between the lower and upper flights. If the landing is framed at the wrong height, every riser in both flights is thrown off — and unequal risers are a leading cause of stairway trips and falls. Getting the height exactly right before you nail anything is the single most important step in landing work.

How Landings Fit Into Riser Math

When you lay out a stair with a mid-stair landing, the landing surface acts like an intermediate floor. You must decide how many risers fall below the landing and how many fall above it. The rule is simple: all risers in the entire stair — both flights combined — must be equal in height.

Start with the total rise: the vertical distance from finished floor at the bottom to finished floor at the top. Divide by the number of risers you plan to use to get unit rise. Then decide how many of those risers belong to the lower flight. Multiply that count by the unit rise; the result is the height from the lower subfloor to the top surface of the landing. The upper flight uses the remaining risers, and its unit rise is identical.

One practical note: the landing surface height you calculate is measured to the top of the finished landing deck — the plywood plus any finish flooring. Frame the platform so the structural plywood lands at the right elevation once finish material is added.

Framing the Landing Platform

A landing platform is essentially a short-span floor system turned on its side and attached to wall framing. The key parts are:

Fasten the ledger first, driving structural screws through the ledger into at least two studs. Use a level to confirm it is horizontal before fastening the rim joists. Build the box frame on the floor or a work surface, then lift it into position and attach the back rim to the ledger. Check for square by measuring diagonals — they must be equal. Install interior joists at 16 inches on center, toenailing or using joist hangers. Lay the plywood deck, glue the top face of each joist, and fasten with screws or ring-shank nails at the spacing your plans specify.

Level and Height Verification

Once the deck is down, grab your 4-foot level and check the platform surface in both directions — parallel and perpendicular to the wall. A level platform means the bubble sits centered on both checks. The allowable tolerance for stair landings in finish carpentry is 1/8 inch over the length of the level — if it reads more than that, identify the high or low corner and correct it before any finish work.

Next, measure from the lower subfloor straight up to the top of the landing deck. Compare that number to your calculated lower-flight height (number of lower risers × unit rise). Then measure from the landing deck to the upper finished floor and compare to the upper-flight height. Both measurements must fall within 1/4 inch of the calculated values. Record all measurements on the landing inspection form before you call the instructor.

Safety on This Task

Fall prevention is the top priority. Working on a platform at height — even a few feet — requires a clear, uncluttered work area. Keep the floor below the platform free of scrap lumber, cords, and tools. Do not stand on the rim joist to reach; reposition yourself.

Tool safety: When driving structural screws with a drill/driver, use the clutch setting appropriate for the screw size to prevent cam-out and bit slippage. Keep your non-driving hand clear of the fastener path. Wear safety glasses at all times; wood chips and screw debris travel at high speed.

Lifting: Dimensional lumber in longer lengths is heavy. Use two-person lifts when moving 8-foot or longer material. Keep your back straight and lift with your legs.

Inspection before load: Never allow anyone to stand on the landing platform until the ledger, all rim connections, and interior joists are fully fastened and you have instructor sign-off. A partially fastened platform can fail without warning.

Filling Out the Inspection Form

The landing inspection form is your quality record. Enter the calculated landing height, the measured actual height, the level readings in both directions, and a check confirming structural fasteners were used at all connections. If any measurement is out of tolerance, note the corrective action taken and re-measure. A complete, accurate form is required for a passing grade on this lab.

Key terms8

LandingA platform built at an intermediate point in a stair run that allows the stair to change direction or provides a rest area; its surface acts as an intermediate floor for riser calculations.
Total riseThe vertical distance from the lower finished floor to the upper finished floor; the starting number for all stair and landing layout calculations.
Unit riseThe height of a single riser, found by dividing total rise by the total number of risers; every riser in both flights must equal this value.
Ledger boardA horizontal piece of dimensional lumber fastened to wall studs with structural fasteners; it supports the back of the landing platform and sets the elevation of the deck.
Rim joistThe perimeter framing member of a platform or floor system that runs along the outside edges; on a landing, the front rim joist faces the open stair.
On center (OC)A framing spacing measurement taken from the center of one framing member to the center of the next; interior landing joists are typically spaced 16 inches on center.
Structural screwA heavy-duty fastener engineered and rated for load-bearing connections; required at ledger-to-stud and rim joist connections on a landing platform.
Level toleranceThe maximum allowable deviation from perfectly level; for a stair landing platform surface, the accepted finish carpentry tolerance is 1/8 inch over a 4-foot level.

Worked examples4

1. A stair connects two floors with a total rise of 108 inches. The designer specifies 14 total risers with a mid-stair landing after the 7th riser. What is the unit rise, and at what height above the lower subfloor should the top of the landing deck sit?
  1. Step 1 — Find unit rise: divide total rise by number of risers. 108 ÷ 14 = 7.714 inches. Round to the nearest 1/16 inch: 7 11/16 inches (7.6875 in). Check: 7.6875 × 14 = 107.625 in — within acceptable tolerance; note this and carry the exact fraction forward.
  2. Step 2 — Identify lower-flight risers: the landing comes after the 7th riser, so there are 7 risers below the landing.
  3. Step 3 — Calculate landing height: 7 × 7.6875 = 53.8125 inches, or 53 13/16 inches above the lower subfloor to the top of the landing deck.
  4. Step 4 — Verify upper flight: remaining risers = 14 − 7 = 7. Upper flight height = 7 × 7.6875 = 53.8125 inches. Total = 53.8125 + 53.8125 = 107.625 inches, confirming both flights use equal risers.
Answer: Unit rise = 7 11/16 inches (7.6875 in). Landing deck height = 53 13/16 inches above the lower subfloor.
2. You are framing the ledger for the landing above. The plywood deck will be 3/4 inch thick, and the finish flooring on the landing will add another 1/2 inch. At what height should you set the top edge of the ledger board so that the finished landing surface ends up at 53 13/16 inches?
  1. Step 1 — Determine total material thickness on top of joists: plywood (3/4 in) + finish flooring (1/2 in) = 1 1/4 inches.
  2. Step 2 — The joists bear on the ledger, and the plywood sits on top of the joists. So the top of the ledger (which equals the top of the joist bearing face) must be below the finished surface by 1 1/4 inches.
  3. Step 3 — Calculate ledger top-edge height: 53 13/16 in − 1 1/4 in = 53 13/16 in − 1 4/16 in = 52 9/16 inches above the lower subfloor.
  4. Step 4 — Mark this elevation on the wall studs before fastening the ledger. Use a level to confirm the mark is consistent across all studs the ledger will contact.
Answer: Set the top edge of the ledger at 52 9/16 inches above the lower subfloor.
3. After framing and decking the landing, you place a 4-foot level on the platform and the bubble reads 3/16 inch off center (high on one side). Does this pass or fail the level tolerance, and what is the next step?
  1. Step 1 — Identify the tolerance: landing platform must be level within 1/8 inch (2/16 inch) over 4 feet.
  2. Step 2 — Compare measured deviation to tolerance: 3/16 inch > 2/16 inch (1/8 inch). The platform fails the level check.
  3. Step 3 — Identify the high corner: sight along the level and mark which end is high. Check the joist bearing at that corner — a shimmed ledger or a joist that is crowned could be the cause.
  4. Step 4 — Correct the issue (trim a high spot, add a shim at a low bearing, or reposition the ledger) and re-check with the level. Record corrective action and new measurement on the landing inspection form before calling the instructor.
Answer: Fail — 3/16 inch exceeds the 1/8-inch tolerance. Identify and correct the high corner, then re-measure and document.
4. A landing platform box measures 48 inches × 36 inches. You measure both diagonals to check for square. One diagonal is 60 1/4 inches and the other is 59 7/8 inches. Is the box square, and by how much are the diagonals off?
  1. Step 1 — Convert both measurements to a common fraction base. 60 1/4 in = 60 2/8 in; 59 7/8 in = 59 7/8 in. Convert to eighths: 60 2/8 in vs. 59 7/8 in.
  2. Step 2 — Find the difference: 60 2/8 − 59 7/8 = 59 10/8 − 59 7/8 = 3/8 inch.
  3. Step 3 — A square box has equal diagonals. A difference of 3/8 inch means the box is out of square. Push the corners with the longer diagonal toward each other (rack the frame) until both diagonals are equal, then recheck.
  4. Step 4 — Once diagonals are equal, fasten the corners fully and recheck with the level to confirm racking did not tilt the frame.
Answer: Not square — diagonals differ by 3/8 inch. Rack the frame to equalize diagonals before final fastening.

The math in this lesson2

Learners divide 108 in by 14 risers, set ledger height for decking and flooring, and compare landing diagonals.
N-Q.1N-Q.3
Brush up in the math halls at newSchoolWorks.com:
In class: Landing-height calculation: students recalculate unit rise for an L-shaped stair scenario with a mid-stair landing, determining how many risers occur below and above the landing and confirming all risers remain equal. · Platform framing: students build a landing platform box from dimensional lumber—rim joists, interior joists at 16 inches on center, and a plywood deck—to match the calculated landing height, fastening to wall studs with structural screws through a ledger board. · Level and height verification: students use a 4-foot level and tape measure to confirm the platform surface is level in both directions and that the height from subfloor to landing and from landing to upper floor divides into equal risers as calculated. Record on a landing inspection form.
Materials: Dimensional lumber (2×8 or 2×10 per design), 3/4-inch plywood, structural screws, drill/driver, 4-foot level, tape measure, chalk line, landing inspection form, wall-framing mock-up with studs
Check: Instructor reviews landing inspection form: platform level within 1/8 inch in both directions, height within 1/4 inch of calculated value, all framing connections made with structural fasteners. Pass = all three criteria met.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

NCCER Carpentry — Stair Layout and Construction
1. A stair has a total rise of 90 inches and 12 total risers. The landing is placed after the 6th riser. What is the height of the landing deck above the lower subfloor?
NCCER Carpentry — Stair Layout and Construction
2. Why must all risers in both flights of an L-shaped stair — including the rise onto the landing — be equal in height?
NCCER Carpentry — Floor and Platform Framing
3. When fastening a landing ledger board to wall studs, which type of fastener is required?
NCCER Carpentry — Stair Layout and Construction
4. After framing a landing platform, you place a 4-foot level across the deck and the bubble is centered, but when you rotate the level 90 degrees the bubble drifts 3/16 inch off center. What should you do?
NCCER Carpentry — Floor and Platform Framing
5. You measure the two diagonals of a 48-inch × 36-inch landing platform box and get readings of 60 1/8 inch and 60 1/8 inch. What does this tell you?
NCCER Carpentry — Floor and Platform Framing
6. Interior joists in a landing platform are typically spaced at:
OSHA 10 — Fall Hazards
7. Which OSHA 10 hazard control is most directly relevant to working on an elevated landing platform during framing?
NCCER Carpentry — Stair Layout and Construction
8. A landing platform is framed and the measured height from the lower subfloor to the top of the plywood deck is 52 1/2 inches. The calculated required height is 52 3/8 inches. Does this meet the height tolerance for the lab inspection?
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