New houses near railways
There are comparatively few train lines in New Zealand compared to the number of roads.
However, when houses are located near train tracks, the noise impact on those houses and their occupants can be significant. Heavy trains can make a lot of noise.
KiwiRail encourages local councils to require that new houses built near railway lines be soundproofed and be certified as soundproofed. This is to avoid situations developing where new homeowners cannot sleep in new houses built next to important national infrastructure.
Typically, proposed new homes within 70m of an existing train line will require an acoustics certificate.
How does the design and certification process work?
The process for doing a railway noise soundproofing design for a proposed new house is slightly different to the process for doing a road noise soundproofing design. Road noise can be predicted from averaged road traffic counts, roads surfaces etc. But rail traffic data on many New Zealand rail lines is hard to source.
So, to work around this, KiwiRail recommends working to design guidelines of LAeq 1hour 70dB at 12m distance from the railway line (LAeq = simplified, this is the logarithmically averaged sound level). Using this, I can model how loud the railway noise will be at a proposed new house site. From there, I certify what soundproofing is required for the new house.
To create a computer model and to make a railway noise assessment, I use my specialist library of ground terrain data and my specialist noise modelling software to create a model of the ground terrain. Then, because trains of unknown weight, size, speed, drive type and frequency are difficult to model in terms of noise impact, I model the train noise as being LAeq 1 hour 70dB at 12m from the rail tracks, as per KiwiRail recommended guidelines. Working from these guidelines, I can model and certify what agreed value of soundproofing is required for the new house.
What building design modifications are typically involved?
What does a railway noise acoustic design certificate for a new building usually cost?
Give me a call, tell me about your building. Then I’ll quote the cost of the report for you on the phone. But a simple railway noise building soundproofing design certificate is typically around $1,000 – $1,200 + GST.
How long does it typically take to get a railway noise acoustic design certificate?
I can often turn railway noise soundproofing design reports around in 2-3 days. Sometimes it’s even quicker if you are really stuck.
When are railway noise soundproofing acoustic design certificates usually required by council?
Typically when a new residential building is located within, say, 80m of an existing railway line.
What additional information does the client need to supply?
Items that I need from the client are copies of the building plans and preferably copies of the resource consent condition or RFI.