# LDD-19 · Doors + Stairs

> **Status:** 🟢 LOCKED.

## One-line intent

Consistency > uniqueness for doors; comfort + openness for stairs.

## Why this matters

Two small LDDs that punch above their weight. 84" doors throughout (vs default 80") + a 54"-wide stair (vs default 36–42") are two of the cheapest moves available to upgrade daily experience for the next 50 years.

## Locked decisions

**Doors**

| Spec | Value |
|---|---|
| Height | 84" slab doors |
| Construction | Solid core |
| Style | Flat, minimal |
| Cost target | $50–$150 per door |
| Rule | **Consistency > uniqueness** |

**Stairs**

| Spec | Value |
|---|---|
| Risers | 21 |
| Rise height | ~6.85" |
| Tread depth | 11" |
| Width | 54" |
| Run | ~18' |

**Intent**

- Stair feels comfortable, generous, and open.
- Doors feel consistent and minimal across the entire building.

## Open items / requires engineer review

- **Total door count** — needs takeoff. For a building with ILS + 2 baths + bedrooms + workshop WC + LOW + mech + multiple closets, count is probably 25–40 doors.
- **Door hardware spec** — matte dark to match exterior? Brass with patina? The LDD doesn't say.
- **Door swing direction + clearances** — needs floor plan to lock.
- **Stair construction** — wood treads + steel stringers? Concrete? Open or closed risers? Affects acoustics (closed = quieter) and cost.
- **Stair handrail spec** — per LDD-18 material language: steel + wood cap.
- **Stair guard rail** at landing(s) and any open side.
- **Code compliance** — 6.85" rise × 11" tread = 17.85" formula = compliant with most IRC (≤ 7¾" rise, ≥ 10" tread, formula 24–25"). Verify with AHJ.
- **Accessibility / aging-in-place** — the ILS is aging-in-place; does it need stair-free routing or a separate ground-floor entrance? (Yes, since ILS appears to be ground-floor-only based on program.)

## Cross-references

- → [LDD-18 interior materials](18-interior-materials.md) — steel + wood cap rail.
- → [LDD-17 soffit](17-soffit-system.md) — stair edge lighting on low-level navigation layer.
- ← [LDD-08 lighting](08-lighting-framework.md) — low-level navigation lighting on stair.

## Cost drivers

**Doors:**

- 25–40 slab doors at $50–150 (door only, no hardware) = **$1.25–6K** for doors.
- Hardware (hinges, latch, lever) at $20–80/door = **$0.5–3.2K**.
- Pre-hang + frame + install: $200–400/door labor = **$5–16K**.
- Specialty doors (mech room smoked glass, ILS pocket, possibly upstairs pocket doors): **$3–8K** additional.

**Total doors: $10–35K**, depending on count + hardware tier.

**Stairs:**

- 54"-wide, 18' run, 21 riser stair in wood + steel + handrail + guardrail + finish: **$12–28K** depending on tread material and construction.

**Likely-case rollup: $22–60K combined doors + stairs.** Budgeted in $110K finish line of waterfall.

## Air-gap concerns

1. **"Consistency > uniqueness" is the right rule and easy to break.** When buying 30 doors, the temptation to "make the master bedroom door special" is real. Don't.
2. **84" doors look great until you hit the IMP envelope.** Tall doors at exterior walls need taller rough openings and taller head flashing. Coordinate with envelope detail.
3. **54" stair is wide.** It's at the top end of residential and looks generous. Make sure code doesn't require dual handrails at that width (some jurisdictions do above 44").
4. **Handrail height + child safety.** With 21 risers from ground to upper, the open-stair side has a serious fall risk. Guardrail height code compliance is the floor; if there are children, design for it.
5. **Stair acoustic.** A 54" wide open stair conducts sound from upstairs to living wing very effectively. Closed risers + carpet runner (or recessed acoustic on underside) help; spec now.
6. **Stair as architectural feature.** With this width and openness, the stair is a major visual element. Don't treat it as utility — invest in the tread material and handrail detail. The LDD-18 steel + wood cap rail will read on this stair more than anywhere else.

## Diagram

(no dedicated SVG — geometry implicit in stair spec.)

## Status

🟢 **Green — smart comfort calls without overspend.**