Noise - Environmental  - Home Insulation - Fencing

Fencing for Noise Control

To be effective, the top of the fence or wall must cut the line of sight - if you can still see the noise source, the fence isn't really effective; hopefully most, if not all, of the noise source should be screened.

As an example, let us suppose that a house has a busy road at the bottom of its garden; we can build a fence, wall or barrier that would reduce traffic noise by 15 dBA if the whole road were screened. however, if this barrier was built solely at the bottom of a garden (say 20m long and 10m wide), very little of the road would be screened and noise levels at the house would only fall by 1 dBA, which is not worthwhile; if the barrier could also built at along the bottom of the two gardens either side, noise levels would fall by 3 dBA - still probably not worthwhile. It is only if the barrier screens the whole road that the full potential reduction of 15 dBA can be achieved; therefore, it needs to be built at the bottom of the garden and up the sides of the garden, or along virtually the whole roadside edge.

The barrier also has got be heavy enough, such that the amount of noise passing through the fence is not significant*.  For the same reason gaps and cracks should be eliminated; consequently the cheapest fencing material - larch or waney lap, simply isn't suitable, because it is too lightweight and has too many gaps. Feather-edge fencing may be suitable. Brick and block walls are heavy and well-sealed enough; with concrete panel fencing, care should be taken over sealing. The directory can be consulted for details of specialist fencing suppliers.

* There is a formula given in the DTp Document to calculate the necessary mass per unit area as follows:

m = 3 x Antilog [ (10+A)/(-14) ]

where

m = mass per unit area kg/m2

A = barrier attenuation in dB (always -ve)

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