# LDD-04 · West Gym Hero Wall (Clerestory)

> **Status:** 🟢 LOCKED v2.1 — replaces all prior clerestory concepts.

## One-line intent

A protected center with a disciplined daylight crown — basketball dominates, light supports.

## Why this matters

The west wall is the gym's defining face and the project's most photogenic single element. The discipline of "no glass behind the hoop" is rare and correct: it acknowledges that this is a real basketball court, not a decorative one, while still preserving the daylight quality that makes the gym pleasant year-round.

## Adjacent functional walls (per builder drawings)

The gym is bounded on its short ends by two purpose-built interior walls that are not part of this LDD but coordinate with it:

- **Ballet wall** (north end, between gym and ILS) — likely mirrored / barre-equipped surface for stretching, ballet, and warm-up.
- **Rebound wall** (south end, between gym and the south bay equipment / workshop zone) — designed for ball-rebound practice (basketball, soccer drills).

These walls confirm the gym is intended as a **multi-sport athletic training environment**, not just a basketball half-court. The west hero wall should not visually compete with these working surfaces.

## Locked decisions

**Composition hierarchy**

- Center field → basketball (no glazing)
- Upper field → daylight crown (two rows of clerestory)

**Clerestory system**

- Two rows of glazing
- 24" height each
- Total height ~48"
- 16' module runs subdivided into 4' sub-modules

**Central no-glazing field**

- ~12' wide
- Contains 72" backboard + ~3' buffer each side
- Backboard may overlap clerestory visually when retracted, but **must not interfere physically**

**Horizontal layout**

- Clerestories on left and right of center field only
- Perfect symmetry

**Vertical placement**

- Clerestory bottom is above active play zone
- Buffer zone below clerestory before active play height

## Prohibited

- Glass behind hoop
- Irregular modules
- Oversized spans
- Anything that puts the daylight system in competition with the play surface

## Open items / requires engineer review

- Final clerestory glass: laminated safety, Low-E, U-value target.
- East-facing equivalent? The doc names the west wall as hero; the east wall (living wing exterior) gets no equivalent specification in the LDD set. Confirm intent.
- Rain-screen detail at clerestory head/sill on a metal IMP wall — flashing detail is non-trivial.
- Shade strategy: 48" of clerestory glass facing west in summer afternoon will cook a basketball gym. Address explicitly: interior shades, exterior shading, frit pattern, Low-E selective glass, or all of the above.
- Backboard mount detail — the LDD-22 basketball hoop system is slab-anchored, but if the backboard is retractable, the retraction kinematics must clear the clerestory.

## Cross-references

- ← [LDD-01 structural](01-structural-pemb.md) — clerestory glazing sits within PEMB girt rhythm.
- ← [LDD-22 basketball hoop](22-basketball-hoop.md) — backboard placement defines the central no-glass zone.
- → [LDD-11 envelope](11-exterior-envelope.md) — clerestory head/sill interface with IMP wall.

## Cost drivers

- **Clerestory glass + frame**: 48" × ~48' of glazing (2 × 24" × 24' each side) ≈ ~190 sqft. At $100–160/sqft for thermally broken aluminum + laminated Low-E + operable (likely fixed only) ≈ $20–30K. Operable units add $400–800/unit.
- **Solid wall under and central zone**: covered by LDD-11 envelope.
- **Backboard and hoop**: covered by LDD-22 (likely $8–14K for slab-anchored independent steel frame + pro-grade rim/glass backboard).
- **Shading strategy** if needed (interior motorized shades on 48' of clerestory): $5–12K.

**Likely-case rollup: $55–90K for west gym wall glazing system including shading.**

## Air-gap concerns

1. **West-facing solar gain is the killer.** 48 ft × 48 in = ~190 sqft of west-facing glass admitting late-afternoon sun in summer. Even with Low-E this will heat the gym substantially. The HVAC strategy uses 2 mini-splits + destratification fans — that needs to handle this load, and the radiant slab is a poor cooling tool. Insist on a real solar load calculation and shading strategy. Without it, the gym becomes a 100°F afternoon space May–September.
2. **Glare on the court.** Sun angles in late afternoon will project glare strips onto the court. Frit pattern, exterior screen, or motorized interior shades — all add cost and visual complexity to the "disciplined crown."
3. **"Backboard may overlap visually when retracted but must not interfere physically."** This sentence is doing a lot of work. If the backboard is retractable (vs. fixed), the retraction path needs explicit clearance against clerestory glazing, mullions, and operator hardware. Detail before glazing order.
4. **Air handler / mini-split visibility from the gym side.** The gym's two mini-splits will be visible. The hero wall is glass-crowned; the rest of the gym ceiling/wall plane will have mini-splits, destratification fans, and clerestory-related wiring. Coordinate aesthetically.

## Diagram

![West gym hero wall elevation with clerestory rows and central no-glass zone](../../diagrams/04-west-gym-elevation.svg)

## Status

🟢 **Green — the constraint discipline is the strongest in the doc set.** Resolve solar gain and glare strategy as detail design starts; otherwise locked.