✓ Report issued
Light industrial
Location
Gretton, Northamptonshire
Planning authority
North Northamptonshire Council
Application
Not yet listed on the public register
Decision
Not yet confirmed on the public register
Development
Residential outbuilding to a single-operator furniture-making workshop
Standards
BS 4142:2014+A1:2019, ISO 9613-2:2024, BS 7445-2:1991
A furniture maker planned to move a bespoke workshop into an outbuilding behind a village home. The nearest homes are between 10 and 24 metres away, so the planning case depended on showing that machinery noise could be properly controlled.
The Scheme
The proposal changes the use of an existing outbuilding at the rear of a house from residential to a commercial workshop, run by a single craftsperson making bespoke furniture. Use is limited to 09:00–19:00, and typical working is expected to be between 10:00 and 15:00.
The Noise Issue
Table saws, a spindle moulder, a router, a planer/thicknesser and dust extraction are loud, and the existing timber doors were the weak point in the building. Without mitigation, the BS 4142 rating level at the nearest home was up to 12 dB above background, which on its own would indicate a significant adverse impact.
What We Did
01
Ran an unattended 24-hour baseline survey on 27–28 November 2025 and adopted a representative background sound level of 37 dB LA90 for the 09:00–19:00 operating period.
02
Modelled ten items of woodworking equipment and plant to ISO 9613-2:2024, using manufacturer data and worst-case on-times, at the three nearest homes.
03
Applied a +5 dB character correction (+2 dB for tonality and +3 dB for impulsivity), then compared the rating levels with the background level in line with BS 4142.
04
Specified upgrades to the timber doors (from about Rw 20 dB to Rw 28 dB), mineral wool between the rafters to cut reverberation from 2.5–2.7 seconds to 1.0–1.4 seconds, and a Noise Management Plan.
The Result
37 dB
Representative background level, LA90
36 dB
Mitigated rating level at the nearest home
28 dB
Target sound reduction of the upgraded doors, Rw
Planning Outcome
With the specified mitigation in place, the predicted rating levels fall below the 37 dB background level at every assessed home, from 36 dB at the nearest. Under BS 4142 this indicates a low impact, and the report concluded that the workshop is acoustically acceptable provided the measures are fully installed and maintained.
Related services and guides
Noise impact assessments for planning →
Decision details are taken from the council's public planning register and can be checked by searching the application reference on the council's planning portal. Client and site details are kept confidential.
