SSOT v3.7 · Contractor Detail Drawing · Acoustic Design Basis

Wall Assembly Cross-Sections

Horizontal slices through wall types W1–W6. Layer colors are locked across all details for fast contractor coordination, and total thicknesses are dimensioned in purple.

Wall Types
6 assemblies
Thickest
W1 / W2 · 39 cm
Green Glue
W3, W4, W5 [AC]
Partitions
W3–W6
Concrete Gypsum Green Glue Rockwool Air gap MLV Stud zone

W1 — North Concrete Wall

STC 65 · ~39 cm total

Existing 300 mm concrete (street behind — the ONLY concrete wall on the perimeter, S3-SITE-TRUTH §2) upgraded with RSIC-1 clips, hat channel cavity, 50 mm Rockwool, and two gypsum layers to control reflected energy into the rooms. Never through-fix to the concrete outside the clips.

39 cm total thickness 300 mm concrete RSIC-1 clips + 25 mm cavity 50 mm Rockwool 2 x 12.5 mm gypsum Finish face

W2 — West Diagonal: Existing Gypsum + NEW Independent Inner Leaf [AC]

STC ~60 class (est. 55–60) · ~13 cm new build-up

The existing west diagonal is a GYPSUM stud wall (S3-SITE-TRUTH §2, photo IMG_1291) — NOT concrete, so a clips-on-mass lining is void. Isolation is a free-standing independent inner stud leaf (BOQ PW-02): 70 mm studs set clear of the existing leaf with a ≥25 mm air gap and NO fixings into the existing wall, RWA45 cavity fill, and 2 × 12.5 mm SoundBloc with Green Glue. What is behind the existing wall is UNVERIFIED — ask before any penetration.

~13 cm new build-up (gap + leaf) EXISTING gypsum wall (kept) ≥25 mm gap 70 mm independent studs + RWA45 2 x 12.5 mm SoundBloc + GG NO fixings into the existing leaf — ever Inner leaf stands on the float-floor-side track, decoupled at head and edges

W3 — East Server Wall [AC]

STC 62 · ~26.5 cm total

Decoupled stud leaf against the existing GYPSUM leaf and its ~100 mm air gap to the B313 block wall (S3-SITE-TRUTH §2). B313 is a SERVER ROOM running 24/7 — the existing air gap is the decoupler: keep it UNFILLED and never bridge it. 70 mm studs + Rockwool, double 16 mm gypsum skins with Green Glue on both sides. Green Glue application is mandatory [AC].

26.5 cm total thickness 100 mm existing air gap 2 x 16 mm gyp + GG 70 mm studs + Rockwool 2 x 16 mm gyp + GG

W4 — South Rebuilt Wall [AC]

STC 50 · ~15 cm total

The south wall is an existing GYPSUM interior partition (S3-SITE-TRUTH §2), lined/rebuilt to STC 50 class (BOQ PW-03): gypsum / Green Glue on both faces, 100 mm stud cavity, RW100 insulation. D1 + D5 are NEW FRAMED OPENINGS on structural steel subframes per the IAC doorset schedule (BOQ D-07) — NO concrete cutting, NO lintels; the subframes carry the ~75 kg leaves + slam loads.

15 cm total thickness 2 x 12.5 mm gyp GG 100 mm studs + RW100 GG 2 x 12.5 mm gyp

W5 — Buffer Spine [AC]

STC 55 · ~15 cm total

NEW BUILD (BOQ W-07) — the site is an empty shell; no spine exists and there is nothing to demolish. Double-leaf x=213.6→228.6, full depth y=0→431, independent frames, isolated cavity, head sealed to slab, STC 55 class. It mirrors W4 but remains a dedicated service spine; no door, and the only penetrations are the sleeved, OFFSET SN-03 snake/conduit crossings. Keep framing true because it establishes the offset between the east and west room sets.

15 cm total thickness 2 x 12.5 mm gyp GG 100 mm studs + Rockwool GG 2 x 12.5 mm gyp

W6 — VO / Control Partition

STC 53 · ~12 cm total

NEW BUILD (BOQ W-10) at y=280 — no prior partition existed on site. Lightweight staggered-stud partition carrying the observation window opening. Maintain the stagger so the opposite gypsum faces are not hard-coupled through the studs. Seal the partition head to the slab (continuous plenum barrier).

12 cm total thickness 2 x 12.5 mm gyp 70 mm staggered studs + RWA45 2 x 12.5 mm gyp