---
title: "Stair Vault (228)"
created: 2026-07-01
updated: 2026-07-01
type: concept
status: compiled
namespace: pattern-language
pattern_number: 228
pattern_name: "Stair Vault"
source_repository: https://github.com/zenodotus280/apl-md
source_url: https://github.com/zenodotus280/apl-md/blob/master/Patterns/Stair%20Vault%20%28228%29.md
license_note: Non-commercial reuse with attribution; see namespace README and source LICENSE.md.
related_patterns:
  - "Floor-Ceiling Vaults (219)"
  - "Staircase as a Stage (133)"
  - "Staircase Volume (195)"
  - "Efficient Structure (206)"
  - "Good Materials (207)"
  - "Floor Surface (233)"
  - "Soft Tile and Brick (248)"
  - "Alcoves (179)"
  - "Child Caves (203)"
  - "Closets Between Rooms (198)"
---

# Stair Vault (228)

> Source pattern from the abridged `apl-md` corpus. Use as a design reference and constraint seed; do not treat as commercial-clean training data.

### Problem
>Within a building technology which uses compressive materials as much as possible, and excludes the use of wood, it is natural to build stairs over a vaulted void, simply to save weight and materials.

### Solution
>Build a curved diagonal vault in the same way that you build your [[Floor-Ceiling Vaults (219)]]. Once the vault hardens, cover it with steps of lightweight concrete, trowel-formed into position.

### Related Patterns
... this pattern helps complete the rough shape and location of stairs given by [[Staircase as a Stage (133)]] and by [[Staircase Volume (195)]]. If you want to build a conventional stair, you can find what you need in any handbook. But how to build a stair in a way which is consistent with the compressive structure of [[Efficient Structure (206)]], without using wood or steel or concrete - [[Good Materials (207)]]?

A lightweight concrete tread, colored, waxed, and polished can be quite beautiful and soft enough to be comfortable - see [[Floor Surface (233)]] - and will eventually take on the patina of wear called for in [[Soft Tile and Brick (248)]].

The vaulted space under the stair can be used as an [[Alcoves (179)]], a [[Child Caves (203)]], or [[Closets Between Rooms (198)]]. If it is plastered, like a regular ceiling - see [[Floor-Ceiling Vaults (219)]], it makes a much more pleasant and useful space than the space under an ordinary stair.

---

> [!cite]- Alexander, Christopher. _A Pattern Language: Towns, Buildings, Construction_. Oxford University Press, 1977, p. 1073.
> #APL/confidence/medium
>
> #APL/Construction-Patterns/Frame-Adjustments