Houses and airports

Several airports in the Waikato and Bay of Plenty regions have noise contour lines areas associated with them. This means that there is a line drawn around those airports on council maps.

Any new building inside that line has to be soundproofed against aircraft noise. This is to ensure that new houses in those areas are quiet enough to sleep in, in order to prevent downstream problems between the airport infrastructure operator and the homeowner.

How do you calculate the level of soundproofing?

When I’m asked to do an airport noise soundproofing design and certificate, I will look at which noise contour line the proposed new house is located inside. This will tell me what amount of soundproofing the proposed new house will need. From there, I can design and certify what soundproofing is required for the new dwelling.

To do a design, I will look at the proposed house construction and the noise contour line it is inside. Then I’ll use my Insul and SonArchitect design software, my soundproofing construction experience and my professional qualification in acoustics to make a specification and write an acoustic design certificate.

What building design modifications are typically involved?

Typically, if I need to increase the soundproofing specification of a facade wall, I’ll add an extra layer of interior plasterboard. It’s easy to understand for builders and designers, easy to implement on-site, and comparatively cheap.

If I need to increase the soundproofing specification of a ceiling/roof interface, I’ll specify an extra layer of interior plasterboard. It’s easy to understand for builders and designers, easy to implement on-site, and comparatively cheap.

Standard modern exterior double glazing will achieve about STC 30. If I need to increase the soundproofing specification of some windows, I’ll typically specify 6.38mm/12mm airspace/5mm monolithic glazing (STC 38). This glazing combination still fits in a standard window frame extrusion and is comparatively cheap.

Mechanical ventilation may need to be specified if a room’s windows need to be kept closed for soundproofing.

If required, typically, this is implemented using a light in-line fan in the ceiling void with 2-3m of flexiduct upstream and downstream of the fan. The fan brings fresh air into the required room from outside, from the quiet side of the building. Sometimes a separate ventilation engineer’s certificate will be required by council. A rough but useful rule of thumb is that you need 4 or more air changes per hour to the targeted room. For example, a 30m cubic metre room will need a fan that pumps 120 cubic metres or more of air per hour.

What does an airport noise soundproofing design certificate for a new residential building typically cost?

Give me a call, tell me about your building. Then I’ll competitively quote the cost of the report for you on the phone. But a simple airport noise building soundproofing design certificate is typically around $1,000 + GST.

How long does it typically take to get an airport noise soundproofing design certificate?

I can often turn airport noise soundproofing design reports around in 2-3 days. Sometimes it’s even quicker if you really need it urgently.

When are airport noise soundproofing certificates for new houses usually required by councils?

Typically, when a proposed new house site is within the airport’s published noise contour lines. For example, google Rotorua Airport noise contour lines.

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.