Drywall partitions for offices: acoustics, glazing, reversibility

Every drywall partition in an office space simultaneously meets three regulatory requirements, to be settled from the design phase.

Installation. The DTU standards govern the metal frame, the layout of the boards and the perimeter junctions, for the common heights of 2.50m to 3.20m under slab. The floor flatness tolerance is set at ±5mm per metre.

Acoustics. NF S 31-080 calibrates the Rw insulation according to use. Standard confidentiality between closed offices or meeting rooms requires Rw=32dB minimum, and Rw≥38dB at management level. The INRS points out that noise remains the most frequently reported nuisance in open spaces, affecting 6 employees out of 10.

Lighting. Article R.232-7-3 imposes a maximum ratio of 5 between general lighting and task lighting levels in workplaces (Filière 3e), which justifies the integration of fixed glazing (transoms, sills or full height) over 30 to 50% of the runs.

The technical response is sized progressively: 48mm frame for a simple visual separation, 70mm for a standard closed office, 90mm for a confidential meeting room. The CF 1/2h or CF 1h fire performance is achieved with BA18 doubling or type F boards, in accordance with the ERP order of 25 June 1980.

The table below summarises composition, measured acoustic performance and the price range recorded on Kytom projects delivered in 2023-2024.

6 projects out of 10 opt for the 70mm frame, considered optimal in terms of performance/footprint/cost ratio. The installation rate is between 80 and 120sqm per team per day. On the closed offices delivered in 2023, the average Rw measured with a sound level meter reaches 44dB, above the common levels required for this type of work. This safety margin is verified by an on-site Rw measurement at handover, in line with the applicable standard: we deliver a measured Rw, not a catalogue Rw.

Fixed glazing simultaneously meets the R4213-1 requirement on natural light and the demand for a perceived image from your users. Three typologies dominate orders.

The glazing fits into the metal frame via U- or T-shaped aluminium profiles and accepts single glazing of 8 or 10mm or acoustic double glazing of 4/16/4. At 2.70m in height, acoustic glazing weighs 25 to 40kg/sqm, which requires a reinforced 90mm frame and anchored fixings on a concrete slab, never on a raised access floor alone. The layout anticipates structural silicone or EPDM gasket junctions, with scheduled maintenance at 8 years to maintain the nominal Rw.

The theoretical performance of a drywall partition collapses at three technical points that we address from the survey stage.

Slab flatness. The DTU standards require a tolerance of ±5mm per metre. Beyond that, floor remedial works become necessary and extend the project by 5 to 10 days. The diagnosis is carried out with a laser from the initial survey, never after the studs have been installed.

Perimeter junctions. A suspended ceiling not partitioned up to the upper slab causes the actual Rw to drop by 8 to 12dB compared with the laboratory value. The correction involves full partitioning or an acoustic plug on the head track, validated with a sound level meter at handover.

Full-height glazing. Integration requires a reinforced 90mm frame and anchored fixings on a concrete slab. The extra cost is between 60 and 90euros/sqm compared with a solid partition, but it secures the acoustic performance over 15 years.

Kytom documents each of these constraints from the study stage and verifies the Rw with a sound level meter at handover. This requirement is part of the network’s specifications.

65% of our office clients reorganise their floors within 5 years of the initial delivery. This figure drives the trade-off between masonry partitions and drywall partitions from the design stage. Removing a drywall partition takes 1 day for 30 to 40 linear metres, compared with 3 to 4 days for a rendered brick partition, with material recovery of at least 70%: crushed boards used as a base layer, remelted metal frame, mineral wool recycled through a dedicated channel. This traceability meets the regulatory obligations to reduce the energy consumption of the office stock.

On an 850sqm reconfigured floor, the average ROI is between 18 and 30 months. The calculation incorporates three levers: the gain in acoustic productivity (documented reduction in HR complaints), the flexibility of future reconfigurations and the asset value enhancement of the property on the office real estate market. Environmental certifications explicitly recognise the demountable drywall partition as a contributor to material credits and the circular economy, an argument that carries weight in owner trade-offs for core and core+ assets.

Our job also involves saying no when the technical trade-off does not hold up. Three configurations call for a different solution.

Permanently wet rooms. Shared sanitary facilities, showers, industrial kitchens: ambient humidity above 80% degrades the moisture-resistant board over the medium term. The masonry partition in moisture-resistant plaster block or aerated concrete remains more durable over 20 years.

Extreme acoustic requirements. Recording studios, ultra-confidential executive boardrooms or medical practices with enhanced confidentiality: beyond Rw 55dB, the decoupled double wall with 100mm wool becomes relevant, sometimes combined with masonry.

Heights above 3.50m. Reception halls, floors with an exceptional high slab: the 90mm frame reaches its deflection limits. We then steer towards an aluminium or steel post-and-beam structure, integrated into the metalwork package.

In these three cases, we orchestrate the trade-off with your technical teams and propose the best-suited alternative, rather than forcing a standard solution outside its scope of use.

1. Technical survey
   Our teams come on site for 5 working days for the laser survey of the grids, the identification of HVAC networks, the identification of technical floors and raised floors. This diagnosis determines the accuracy of the layout and the control of the final Rw.
2. Acoustic and light study
   In 10 days, we calculate the target Rw values per zone according to the acoustic standards applicable to office spaces, size the fixed glazing to comply with the regulatory requirements applicable to workplaces and simulate natural lighting. The deliverable is a zone plan with contractual performance per room.
3. BIM or 2D plan validation
   Within 15 days, we deliver the frame dimensions, the board layout, the floor/ceiling/facade junction details and the materials schedule. This phase locks in the quantities before procurement and limits site uncertainties.
4. Coordinated procurement
   Our 11 branches pool orders: BA13 or BA18 boards, 48/70/90mm studs, 45mm mineral wool at a density of 17kg/m³, made-to-measure glazing (4 to 6 week lead time). Logistics coordination eliminates installation stoppages.
5. Installation and handover with a sound level meter
   Installation in occupied or vacant premises by teams, with actual Rw control using a sound level meter and documented handover within 48h. Traceability follows the standard, with material recovery of at least 70% on the removal of existing partitions.