LDD-03 · Gym/Living Spine Wall
One-line intent
Structural glass spine that unifies gym + living visually while maintaining acoustic, thermal, and structural separation through modular glazing flanking a central 18'×10' glass sectional garage door.Locked decisions
- Location: 60' along central core, gym west / living east
- Structure: spine beam + 2 offset columns, no center column. Three structural spans: north end ~17' · central ~26' · south end ~17'. Per builder, this enables standard steel gauges rather than a 60' unsupported beam, while still hitting the 30' viewing aperture.
- Spine beam supports 18" second-floor assembly above (deck + joists + gypcrete radiant + finish)
- Glazing: ~36"×24" mullion rhythm
- Central: 18'×10' glass sectional garage door, manual counterbalanced preferred
- Solid wall ends: 8' each side, mineral wool, sealed penetrations
South → North wall sequence
| Span | Element |
|---|---|
| 8' | Solid wall |
| 3' | Door |
| 3' | Glass panel |
| — | Structural column |
| 3' | Glass panel |
| 3' | Glass panel |
| 18' | Glass garage door |
| 3' | Glass panel |
| 3' | Glass panel |
| — | Structural column |
| 3' | Glass panel |
| 3' | Door |
| 8' | Solid wall |
Open items / engineer review
- Final glass spec (laminated thickness, gas fill, Low-E surface)
- STC target (basketball impact ~95 dBA — STC 45–50 reasonable)
- Garage door manufacturer + counterbalance hardware
- Door type at 3' positions (swinging vs sliding)
- Threshold detail (slab continuous through door, or break — see LDD-24)
Cost drivers
Glass garage door 18'×10' = $12–24K + hardware $4–7K. Modular glazing ~370 sqft × $80–140/sqft = $30–52K. Solid wall sections ~$10–15K. Total spine wall: $60–95K.Air-gap concerns
- STC across 18' garage door is limiting acoustic factor. Even premium glass garage doors transmit basketball impact. Solid 8' ends are the real acoustic mass.
- Manual 18' door is heavy (600–900 lb) — kid shouldn't operate alone. Consider safety reverse + soft-close.
- Mullion rhythm = 30+ glass panels with seals and hardware. Plan cleaning + replacement procurement.
- Threshold continuity per LDD-24 flush mandate — slab pour must accommodate ~2–4mm finish elevation delta across the 18' opening.
Cross-references
Diagram
South → North sequence: 8' solid · 3' door · glass panels · column · glass · 18' garage door · glass · column · glass · 3' door · 8' solid.