Solid partitions: balancing acoustic stability and usage flexibility

Acoustic performance levels and criteria for offices and associated spaces are structured around three reference thresholds for interior joinery:

• Standard confidentiality: partitions between enclosed offices, Rw ≥ 32 dB, compatible with a 98 mm plasterboard partition with double facing and 45 mm mineral wool.
• Enhanced confidentiality: executive rooms, sensitive meeting rooms, Rw ≥ 38 dB directionally, requires a 120 mm partition with decoupled double framing.
• High confidentiality: boardrooms, HR spaces, Rw ≥ 44 dB, 180 mm masonry partition or 150 mm drywall partition with double BA13 facing on each side.

For collaborative spaces, we apply a DnTA,tr ≥ 30 dB threshold. Projects following an HQE approach tolerate a 5 dB deviation when the thermal and environmental justification offsets the trade-off. Laboratory performance generally drops by 3 to 5 dB under real conditions, a gap to factor in from the acoustic calculation note onward.

Our reading differs from the professional consensus on acoustic sizing. Conventional wisdom pushes towards generous specification to secure handover, but specifying Rw ≥ 44 dB on ordinary enclosed offices generates a significant cost overrun on the partitioning package with no measurable usage benefit, since the required confidentiality does not exceed Rw 32 to 36 dB for standard back-office workstations. High-performance specification is only justified in the presence of an explicitly sensitive use (executive, HR, board, medical), confirmed by mapping in the diagnostic phase.

Three recurring pitfalls that degrade acoustic insulation

Our site feedback isolates three dominant causes of acoustic underperformance at handover.

1. Unanticipated service routing. Late penetrations (HVAC, cabling, sprinklers) generate significant parasitic transmissions and weaken the insulation measured at handover. The initial costing frequently omits fire-stop sleeves and certified acoustic sealing, worsening the gap.
2. Thickness standardisation across the entire floor. Applying a single 98 mm partition in open spaces, enclosed offices and meeting rooms mixes very different requirements (Rw 30 to 44 dB depending on the zones) and inevitably leads to over-specifying certain areas or under-specifying sensitive zones.
3. Late coordination with the technical packages. Acoustic bridges at the partition base (duct routing, electrical skirting) and at the top (untreated plenum) can remove several decibels of theoretical performance, confirmed by the DnT,w handover measurements.

The Kytom response combines an exhaustive technical survey in the diagnostic phase, mapping of acoustic requirements by zone, and coordination with the services from the APS phase. This methodology significantly reduces the reworks observed on projects run as separate packages.

For the architect and the IRB: the solid partition as an arbitrated architectural choice

For the interior architect and the IRB (Real Estate-Reorganisation-Building) manager, the solid partition is not a technical detail: it is a trade-off between architectural intent and operational flexibility over 8 to 12 years. Three specification criteria structure the decision in the APS phase.

• Consistency with the fit-out concept. The solid partitions / movable partitions ratio sets the architectural legibility of the floor. Beyond a majority of solid partitions, the floor loses its reconfiguration capacity; below a third, the high-confidentiality zones (executive, HR, board) are insufficiently materialised.
• Compliance with applicable DTUs. The works fall under the applicable DTUs (plasterboard on framing) for drywall partitions and DTUs for small-element masonry partitions. The CE marking of the products (facings, mineral insulation) must be traced in the DOE to secure handover and ten-year liability.
• Interfaces with the prime architectural packages. The junctions between solid partition and glazed joinery (glass partition, fixed frame) are the dominant source of aesthetic reworks at handover: a layout validated in the PRO phase significantly limits on-site adjustments.

For the IRB on the client side, the central trade-off is financial: each immobilised solid partition represents a significant cost of removal and reinstallation during a future reorganisation, to be anticipated from the diagnostic phase. Mapping confidentiality over 5- and 10-year horizons from the diagnostic onward conditions the overall economics of the usage cycle, not just the initial cost of the package.