Stair feasibility: L-shaped stair with a landing
Four steps up from the entry to a landing, then turns; painted risers, oak treads. 16 risers, floor to floor 10'-6".
L-shaped stair with a landing looks workable in this space, with 2 things that need a closer look: step height and the header over the taller opening. An architect or engineer settles them before you decide.
1. The idea
| As drawn | The What if | |
|---|---|---|
| Form | straight | L-shaped with a landing |
| Steps | 16 risers of 7 7/8 in | 16 risers of 7 7/8 in |
| Treads | 15 of 10 in | 14 of 10 in |
| Width | 3'-5 3/4" | 3'-5 3/4" |
| Landing | none | 1 |
| Footprint | 43 sq ft | 55 sq ft |
- Takes about 11 sq ft of the Entry.
- The opening between the Stair and the Entry goes from 3'-6" by 7'-0" to 3'-6" wide by 9'-4" tall.
2. Does it fit
| Check | Measured in the model | Common rule of thumb | Reading |
|---|---|---|---|
| Step height | 16 risers of 7 7/8 in (10'-6" floor to floor) | about 7 3/4 in at most | Needs a closer lookCould the stair take 17 risers of about 7 3/8 in, with 1 more tread (about 10 in more run) and the top or bottom of the run moved to suit? |
| Tread depth | 14 treads, the smallest 10 in deep | about 10 in at least | Looks workable (little to spare) |
| Even steps | risers all the same, treads all the same | within about 3/8 in | Looks workable |
| Headroom | the least is 6'-8 1/2", over step 4, under the head of the opening in the wall | about 6'-8" at least | Looks workable (little to spare) |
| Width | 3'-5 3/4" wide at the narrowest tread | about 36 in at least | Looks workable |
| Landing | 3'-6 1/2" in the direction of travel, 4'-2" by 3'-6 1/2" | at least the stair's width and about 36 in | Looks workable (little to spare) |
| Handrail | drawn on steps 1 to 4, about 35 1/2 in above the treads | one side of a flight of 4 or more risers, 34 to 38 in high | Looks workable |
| Handrail | drawn on steps 6 to 15, about 35 1/2 in above the treads | one side of a flight of 4 or more risers, 34 to 38 in high | Looks workable |
Rules of thumb from the residential building code most California cities adopt; background knowledge, to verify.
For you: 1 check needs a closer look (step height); the rest look workable on the model's numbers.
3. What it takes
- The opening in the upper floor stays as drawn: the new stair arrives where the drawn one does and clears the floor edge.
- The opening between the Stair and the Entry changes from 3'-6" wide by 7'-0" tall to 3'-6" by 9'-4". That means a new header over it. It leaves about 4 in of wall above the opening, and a header for this span is commonly deeper than that (background knowledge, the engineer sizes it): it may need to sit up in the floor framing or be a steel piece.
- The landing, about 3'-3 1/4" up, needs its own support: framing fixed to the walls beside it, or a post under its open corner.
- A closed stair rides on stringers fixed to the walls beside it, the usual way a framed stair is built.
An engineer: likely needed for the opening, the landing and how the stair is carried. A permit: likely; a new stair is structural work in most California cities (general knowledge; the city confirms).
L-shaped stair with a landing adds cost, mostly the new staircase.
Biggest parts first: the new staircase, the header over the opening and the permit. Not priced yet: structural engineering. Based on published price bands, in words only.
4. Questions for your architect or engineer
- Could the stair take 17 risers of about 7 3/8 in, with 1 more tread (about 10 in more run) and the top or bottom of the run moved to suit?
- Does the wall between the Stair and the Entry carry the floor above, and what header fits over a 3'-6" by 9'-4" opening there?
- How is the landing carried: framed off the walls, or on a post?
- Where the steps or the landing stand more than 30 in above the floor beside them, what guard height and baluster spacing do you want there?
- Headroom passes with little to spare (the least is 6'-8 1/2", over step 4, under the head of the opening in the wall). Does it still pass once the floor and tread finishes go in?
5. Sources, and what we did not check
- The stair as drawn: sheet A3.1 of the Linden House drawings.
- The What if: "L-shaped stair with a landing" as built in the 3D tour. It is not on the drawings.
- Levels, floors, walls and openings: the house model the tour is built from.
- The rules of thumb: the residential building code most California cities adopt, as most California homes are designed to it. Our reading from general knowledge, not checked against your city's adopted edition or its local changes.
- Cost words: based on published price bands, compared in words only.
Not checked:
- Guards: their height, baluster spacing and the guard around the opening upstairs (only open risers and handrails are measured).
- Nosings, tread finishes and how much the finished floors change the first and last risers.
- Structure sizes: the header, the floor framing and any posts. That is the engineer's work.
- Lighting and switches at the stair, and any fire separation (for example next to a garage).
- Your city's own changes to the state rules, and whether a permit is needed. Ask the city or your designer.
A feasibility check, not a construction set and not engineering. It reads the 3D model of the What if against common rules of thumb; an architect or engineer confirms every number before anything is built.