Whole-Home Acoustics

Whole-home acoustics / Isolation

Construction first, panels later

Isolation keeps unwanted noise out and room sound from leaking. Bedrooms, studies and cinemas depend on walls, doors, floors and vibration control — not a panel added afterwards. WELL v2 Sound (S03 Sound Barriers) makes the same point: STC / Rw of walls and doors only hold if flanking paths and door seals are closed.

WELL S03: interior walls between sleep / meeting rooms and regularly occupied space should reach STC / Rw 55; loud rooms (plant, cinema, gym) to other occupied space 60; doors solid-core, STC / Rw at least 30, with seals at head, jambs and threshold.

Bonda walls and floors

Guangdong Bonda (BON-PLUS) isolation boards and floor build-ups are used in homes and cinemas. South China University of Technology tested airborne sound to GB/T 19889.3 / ISO 140-3:

• Composite isolation wall (report 160726-2, 26 Apr 2016): three layers of 24 mm Bonda SBR composite board + joist damping pads + light-gauge studs + 50 mm polyester wool + 150 mm lightweight wall. Weighted Rw 63 dB (C;Ctr = −2;−7). About 61 dB at 500 Hz, 69 dB at 1 kHz.
• 24 mm composite board (report 210603-4, 8 May 2021): 12 mm calcium silicate + 3 mm damping (DPC2101) + 9 mm calcium silicate, about 34 kg/m², single-board Rw 40 dB.
• 20 mm damping board SC-20B: fire performance GB 8624-2012 B1 (B-s1, d0) (Guangzhou Quality Inspection JCWT20240077736).

The floor-isolation method statement (B2-34-021) installs walls → ceiling → floor. Services and HVAC in the cavity must be finished first. Isolators stay about 20 mm off the wall; timber about 10 mm — no rattles. Cavity fill (rock wool, glass or polyester) must not pack the void. Joist faces take damping pads KD-01 / IS-01 (GB 18587-2001 Grade A). Board joints about 4 mm, sealed twice with S-01 strip (TVOC 7 g/L vs 100 g/L limit, GB 18583-2008) plus mastic. Penetrations must be closed.

For cinema, recording and plant rooms, a floating floor or room-in-room is used. GERB spring isolators (natural frequency about 2.5–7 Hz) cut vibration and structure-borne noise above 4 Hz better than slag wool, foam or rubber pads — embedded in the slab or hung beneath it.

Soundbox OFF isolation

Soundbox (Hong Kong) has three lines: engineering acoustics, Howeasy, and OFF isolation / shock. OFF mat G25DX (500 × 500 × 25 mm, EPDM) is a full-floor impact layer; the sheet quotes about 20 dB airborne isolation. Used under floating floors in homes, hotels, private cinemas, HiFi, recording and KTV, it breaks footfall and vibration into the structure.

Sources: SCUT reports 160726-2 and 210603-4; Guangzhou QC JCWT20240077736 / 77733 / 77739; Bonda floor method statement; GERB floating-floor / room-in-room; Soundbox OFF G25DX. Absorption treats reverberation. It will not stop footsteps next door.