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Acoustics

How much sound insulation can I expect between flats?

Short answer

In Belgium NBN S 01-400-1 describes 'normal acoustic comfort': at least 54 dB airborne sound insulation (DnT,w) between flats, and at least 58 dB between new terraced houses.

Apartment cross-section: Wall between apartments: airborne sound DnT,w ≥ 54 dB (higher = better); floor: impact sound L'nT,w ≤ 58 dB between dwellings and ≤ 54 dB towards bedrooms (lower = better).
Apartment cross-section — Wall between apartments: airborne sound DnT,w ≥ 54 dB (higher = better); floor: impact sound L'nT,w ≤ 58 dB between dwellings and ≤ 54 dB towards bedrooms (lower = better). (The text inside the figure is in Dutch.)

Explanation

DnT,w measures how much airborne sound (voices, TV) a partition blocks: the higher, the better. Buildwise published an explanation of it in 2007. The standard is often applied through contracts or building rules. Whether it applies to your home depends on construction year, contract and region.

Rules of thumb

  • Between flats: DnT,w ≥ 54 dB. [SW-S12]
  • Between new terraced houses: DnT,w ≥ 58 dB. [SW-S12]
  • Higher number = better insulation. [SW-S12]

Pitfalls

  • A small opening (back-to-back sockets, a gap around a pipe) can greatly weaken a good wall. [SW-S12]
  • A measurement by an acoustic consultant is needed to show whether a standard is met. [SW-S12]

By region

Belgium
The legal status of NBN S 01-400-1 differs by region and contract; ask Buildwise or a recognised acoustic consultant. [SW-S13]
Netherlands
The Bbl (section on sound insulation between spaces) sets requirements for airborne and impact sound between homes; the exact values are in the Bbl text and could not be confirmed in a primary source in wave 2. [SW-S14]

Search terms

These search terms are in Dutch; only terms that also find a topic in English are links.

geluidsisolatie burenlawaai appartement NBN S 01-400-1 DnT,w

Read also

General information, not personal advice. Check the source and reference date.

Not legal advice. Rules differ by country and region; consult the competent authority.

Sources

  1. SW-S12 Akoestische normeisen woongebouwen NBN S 01-400-1 (overzicht) — Buildwise (voorheen WTCB) (Reference date 2026-09-27)
  2. SW-S13 De nieuwe norm NBN S 01-400-1 — Innovation Paper 09 — Buildwise (Reference date 2026-09-27)
  3. SW-S14 Geluid van bouwwerkinstallaties: regels bij nieuwbouw — Informatiepunt Leefomgeving (IPLO, Rijksoverheid) (Reference date 2026-09-27)

Reference date: 2026-09-27 · Translated with AI from the Dutch original.