The Acoustic Problem Coworking Was Built to Have
WeWork's 2019 internal data showed that acoustic complaints accounted for 47% of all member experience tickets — more than Wi-Fi, temperature, and cleanliness combined. The finding should surprise no one. Coworking spaces combine every acoustic challenge of a modern office and amplify them: diverse activities in a single floor plate, no control over who is sitting next to whom, phone calls adjacent to focus work, and social areas bleeding noise into productive zones. Add video calls — which increased 340% post-pandemic — and the acoustic environment becomes the defining factor in member satisfaction and retention.
The solution is not silence. It is acoustic zoning — designing different areas of the space for different noise expectations and ensuring that sound from one zone does not contaminate another. This guide covers the acoustic design of four distinct zones, the specification of phone booths and focus rooms, sound masking strategy, and WELL v2 compliance for coworking operators.
The Four Acoustic Zones
Every coworking space, regardless of size, should be divided into acoustic zones with distinct performance targets. The zoning concept is borrowed from ISO 3382-3:2012 (open plan office acoustics) and adapted for the multi-activity nature of shared workspaces.
| Zone | Activities | RT60 Target | BGN Target | Noise Tolerance |
|---|---|---|---|---|
| 1. Focus Zone | Deep work, coding, writing, analysis | 0.4–0.5 s | 38–42 dBA (with masking) | Very low — speech should be unintelligible at 3 m |
| 2. Hot Desk Zone | General work, light collaboration, emails | 0.5–0.6 s | 42–45 dBA (with masking) | Moderate — speech unintelligible at 5 m |
| 3. Collaboration Zone | Team discussions, informal meetings, brainstorming | 0.6–0.8 s | 45–50 dBA (ambient) | High — speech expected, reverberation controlled |
| 4. Community Zone | Kitchen, lounge, social area, events | 0.6–1.0 s | 50–55 dBA (ambient) | Very high — social noise expected |
Zone Transition Management
The critical design challenge is managing transitions between zones. Sound does not respect painted floor lines. Three strategies control cross-contamination:
- Physical separation: Partitions, glazing, or distance between zones. A 3 m buffer zone between focus and collaboration areas, filled with circulation or storage, reduces speech level by approximately 5–8 dB.
- Acoustic barriers: Full-height or partial-height screens with absorptive surfaces. Per ISO 3382-3:2012 §4, screens of 1.4 m height above desk level provide approximately 5 dB of speech attenuation. Full-height (floor to ceiling) screens provide 10–15 dB.
- Sound masking differential: Running sound masking at different levels in different zones (e.g., 42 dBA in focus, 38 dBA in collaboration) creates a perceptual transition. The higher masking in the focus zone covers more speech from the collaboration zone.
Phone Booths: The Most Abused Acoustic Element
Phone booths are the most requested and most disappointing element in coworking design. Members expect phone-booth-level privacy. Most booths deliver telephone-box-level privacy — you can hear every word.
Why Most Phone Booths Fail
The acoustic performance of a phone booth depends on its composite STC rating — the weakest link in the enclosure. Most booth failures trace to three causes:
- Door seals: Acoustic booths need perimeter gaskets that compress against a flat frame when the door closes, plus a drop-bottom seal that meets the floor. Missing or worn seals reduce composite STC by 5–10 dB.
- Ventilation openings: Phone booths need ventilation (CO₂ builds up rapidly in a 2 m³ space with one person). Unsilenced ventilation openings create direct sound paths. Ventilation must use silenced ducts or transfer grilles with acoustic lining.
- Glass panels: Single-glazed glass (typically 6mm) achieves only STC 28–30. For a booth that claims STC 35, the glass must be laminated acoustic glass (8.8mm or 10.8mm) or double-glazed.
Phone Booth Specification
| Parameter | Minimum Requirement | Premium Target | Standard Reference |
|---|---|---|---|
| Composite STC (including door) | STC 33 | STC 38 | ASTM E413 |
| Internal RT60 | ≤ 0.4 s | ≤ 0.3 s | ISO 3382-2:2008 §A.1 |
| Ventilation rate | 15 L/s per person | 20 L/s per person | ASHRAE 62.1 |
| Ventilation noise | ≤ NR 30 | ≤ NR 25 | BS 8233:2014 |
| Internal volume | ≥ 2.0 m³ | ≥ 2.5 m³ | Occupant comfort |
| Speech privacy from 2m external | STI ≤ 0.30 | STI ≤ 0.20 | IEC 60268-16:2020 §4 |
Testing a Booth Before Purchase
Before committing to a fleet of booths (typically 3–8 per coworking space at £3,500–£8,000 each), test one:
- Sit inside with the door closed. Have someone stand 1 m outside and speak at normal conversational level (60 dBA at 1 m).
- Can you understand specific words? If yes, the booth fails for incoming noise.
- Now reverse: sit outside, 2 m from the booth. Have someone inside speak normally.
- Can you understand words? If yes, the booth fails for outgoing noise (speech privacy).
Focus Rooms: Enclosed Quiet Zones
Focus rooms (single-person or 2–4 person quiet rooms) serve members who need concentration without interruption. They differ from phone booths in two ways: they are larger (8–15 m²) and occupants stay for extended periods (1–4 hours).
Acoustic Requirements
- RT60: ≤ 0.5 seconds per ISO 3382-2:2008 §A.1. In a 10 m² room with 3 m ceiling (30 m³ volume): A_required = 0.161 × 30 / 0.5 = 9.66 m² Sabine. An absorptive ceiling (10 m² at NRC 0.85 = 8.5 m² Sabine) plus one absorptive wall panel (2 m² at NRC 0.85 = 1.7 m² Sabine) meets this target.
- Background noise: ≤ 35 dBA from building services, per WELL v2 Feature 74 Part 1. HVAC must be whisper-quiet — undercut door gaps or transfer grilles must be acoustically treated.
- Sound insulation: STC 40–45 composite. A single-stud plasterboard partition to soffit (STC 44) with a solid-core door (STC 33) and perimeter seals delivers approximately STC 38 composite. Adding a second layer of plasterboard raises the wall STC to 50, improving the composite to STC 40.
Glazing Considerations
Focus rooms often include a glazed element for visual connection and to prevent claustrophobia. Standard single-glazed (6mm) provides only STC 28. Acoustic alternatives:
| Glazing Type | STC | Cost Premium vs Single Glazed |
|---|---|---|
| Single glazed (6mm) | 28 | Baseline |
| Laminated (6.8mm) | 32 | +20% |
| Laminated (10.8mm) | 36 | +40% |
| Double glazed (6-12-6, standard) | 33 | +50% |
| Double glazed (10-50-6, acoustic) | 42 | +100% |
For focus rooms in coworking, laminated 10.8mm glass (STC 36) offers the best value: it is a single pane (thinner frame), costs moderately more than standard glass, and provides adequate insulation when combined with STC 44+ walls and an STC 33 door.
Sound Masking Strategy
Sound masking is arguably the most important acoustic technology in coworking design, yet it is the most frequently omitted. Without masking, a coworking space with 42 dBA background noise from HVAC will have speech intelligible at 8–10 m in the hot desk area. With masking calibrated to 43 dBA (shaped spectrum), speech intelligibility drops below STI 0.50 at 5 m.
How Sound Masking Works in Coworking
Sound masking uses small speakers (typically mounted above a suspended ceiling) to generate a uniform, broadband noise signal shaped to mask the frequency range of human speech (200–4000 Hz). It does not reduce noise — it raises the noise floor so that speech signals from distant workstations fall below the masking level and become unintelligible.
Zone-Specific Masking Levels
| Zone | Masking Level | Spectrum | Purpose |
|---|---|---|---|
| Focus Zone | 42 dBA | Pink noise, 200–4000 Hz | Maximum speech privacy |
| Hot Desk Zone | 40 dBA | Pink noise, 200–4000 Hz | Moderate speech privacy |
| Collaboration Zone | 38 dBA (or off) | Pink noise, 200–4000 Hz | Light masking only |
| Community Zone | Off | N/A | Social noise expected |
Cost: Sound masking systems for coworking typically cost £18–£28/m² of floor area (installed, including commissioning). For a 300 m² space, budget £5,400–£8,400. The system requires professional calibration after installation — uniform ±2 dBA spatial variation per WELL v2 Feature 74 Part 2.
Worked Example: 300 m² Coworking Space
A coworking operator is fitting out a 300 m² shell-and-core commercial space (ceiling height 3.0 m, total volume 900 m³) with the following programme:
| Zone | Area | Programme |
|---|---|---|
| Focus Zone | 60 m² | 12 single desks with high screens |
| Hot Desk Zone | 100 m² | 24 hot desks, low screens |
| Collaboration Zone | 50 m² | 2 × 6-person meeting rooms (15 m² each), 1 × boardroom (20 m²) |
| Community Zone | 60 m² | Kitchen, lounge, social seating |
| Phone Booths | 8 m² | 4 single-person booths |
| Circulation | 22 m² | Corridors, reception |
Step 1: RT60 Targets by Zone
Focus Zone (60 m² × 3.0 m = 180 m³): RT60 target = 0.45 s. Required absorption: A = 0.161 × 180 / 0.45 = 64.4 m² Sabine.
Available: ceiling (60 m² acoustic tile, NRC 0.90 = 54.0), carpet (60 m², NRC 0.35 = 21.0), walls (high screens, NRC 0.50 = ~8.0 m²). Total: 83.0 m² Sabine. Predicted RT60 = 0.161 × 180 / 83.0 = 0.35 s. Exceeds target — the zone will feel comfortably quiet.
Hot Desk Zone (100 m² × 3.0 m = 300 m³): RT60 target = 0.55 s. Required absorption: A = 0.161 × 300 / 0.55 = 87.8 m² Sabine.
Available: ceiling (100 m² acoustic tile, NRC 0.90 = 90.0), hard floor (100 m², NRC 0.05 = 5.0), task chairs (24 × 0.40 = 9.6). Total: 104.6 m² Sabine. Predicted RT60 = 0.161 × 300 / 104.6 = 0.46 s. Within target — per ISO 3382-2:2008 §A.1.
Meeting Rooms (15 m² × 3.0 m = 45 m³ each): RT60 target = 0.5 s. Required absorption: A = 0.161 × 45 / 0.5 = 14.5 m² Sabine.
Available per room: ceiling (15 m² acoustic tile, NRC 0.90 = 13.5), carpet (15 m², NRC 0.35 = 5.25), 6 upholstered chairs (6 × 0.45 = 2.7). Total: 21.45 m² Sabine. Predicted RT60 = 0.161 × 45 / 21.45 = 0.34 s. Well within target.
Step 2: Sound Insulation
| Partition | Target STC | Specification |
|---|---|---|
| Meeting room to hot desk | STC 45 | Double plasterboard each side, 90mm stud, 50mm mineral wool, to soffit |
| Focus zone boundary screen | — | 1800mm high freestanding acoustic screen, NRC 0.70 |
| Phone booth | STC 35 composite | Proprietary booth with tested certificate |
| Community zone to hot desk | STC 35 | Single plasterboard each side, 70mm stud, 50mm mineral wool |
Step 3: Sound Masking
| Zone | Area | Masking Level | Speaker Count (approx.) |
|---|---|---|---|
| Focus Zone | 60 m² | 42 dBA | 4 speakers (1 per 15 m²) |
| Hot Desk Zone | 100 m² | 40 dBA | 6 speakers |
| Collaboration/Community | 110 m² | Off | 0 |
| Total | 160 m² | 10 speakers |
Step 4: Budget
| Element | Quantity | Unit Cost | Total |
|---|---|---|---|
| Acoustic ceiling tile (NRC 0.90) | 300 m² | £45–£65/m² | £13,500–£19,500 |
| Meeting room partitions (STC 45) | 40 m² (wall area) | £85–£130/m² | £3,400–£5,200 |
| Meeting room doors (solid-core, sealed) | 3 doors | £800–£1,200 each | £2,400–£3,600 |
| Phone booths (STC 35) | 4 units | £4,500–£6,500 each | £18,000–£26,000 |
| Acoustic desk screens (focus zone) | 12 screens | £350–£550 each | £4,200–£6,600 |
| Sound masking system | 160 m² | £22/m² average | £3,520 |
| Acoustic commissioning | Lump sum | £4,000–£6,000 | |
| Total acoustic package | £49,020–£70,420 | ||
| Per m² of gross floor area | 300 m² | £163–£235/m² |
This represents approximately 13–18% of a typical coworking fit-out cost of £1,200–£1,400/m². The phone booths alone account for 37% of the acoustic budget — worth comparing proprietary booth costs against bespoke construction, which can be 30–40% cheaper for equivalent or better acoustic performance.
WELL v2 Compliance for Coworking
Many premium coworking operators pursue WELL certification as a membership differentiator. The acoustic requirements map directly to the zone-based design approach:
| WELL Feature | Requirement | How It Maps to Coworking Zones |
|---|---|---|
| S01 (Sound Mapping) | Identify and address noise sources | Zone transition management |
| S02 (Maximum Noise Levels) | BGN ≤ 45 dBA open plan | Hot desk and focus zone compliance |
| S03 (Sound Barriers) | STC 45 between enclosed rooms and open plan | Meeting room partition specification |
| S04 (Sound Absorption) | RT60 ≤ 0.6 s in enclosed rooms | Meeting room and focus room ceiling/walls |
| S05 (Sound Masking) | 40–45 dBA, ±2 dBA uniformity | Focus zone and hot desk zone masking |
The zone-based approach makes WELL compliance natural: each zone has defined targets that correspond to WELL features. The main challenge is ensuring that phone booths and focus rooms meet both the RT60 and background noise requirements simultaneously — booths with noisy ventilation fans are a common failure point.
Five Rules for Coworking Acoustics
- Zone first, decorate second: Establish acoustic zones before selecting finishes. The zone layout determines where absorption, insulation, and masking are needed.
- Test booths before buying: Request a composite STC test certificate (ASTM E90/E413) and test one unit on-site before ordering a fleet. A booth that fails acoustically is an expensive cupboard.
- Ceiling is king: An absorptive ceiling (NRC ≥ 0.85) across the entire space solves 60–70% of reverberation issues. It is the single highest-impact acoustic element per pound spent.
- Sound masking is not optional: Without masking, the focus zone and hot desk zone will have speech intelligibility problems that no amount of absorption can solve. Budget for it from day one.
- Measure and prove: Commission acoustic measurements after fit-out. The data protects you against member complaints ("we tested — the room meets the international standard") and supports WELL certification if pursued.
Further Reading
- Open Plan Office Acoustic Design Guide — comprehensive guide to open plan acoustics with ISO 3382-3 parameters
- Acoustic Design for Interior Designers — material selection guide for interior design professionals
- WELL v2 Feature 74 Decoded — complete technical breakdown of WELL acoustic requirements