The Wind Rose

When researching the new east shed (the west shed option being abandoned) I had come across wind loading calculation sites to determine the following:

Region A – Victoria (A5 – within 70km of Melbourne).

Terrain 3 – Some obstructions (we have more than this)

Shielding – 2 At least 2.5 trees per acre. (we actually have better shielding than this, say Shielding 2.5.)

Slope 4 – between 1 in 5 and 1 in 3.

Location 3 – Top third of of a hill

Total Rating N4 according to sheds online.

N4 Non-Cyclonic = Gus Wind Speed = W50 meters per second. If we have terrain 2.5 then we get to W41.

I thought I would go over to the BOM and see what real measurements they have. There are two weather stations up here. I use the Moint Dandenong one when we can as we are high up on its slopes. But it is a very basic one and the ferny creek one (previously Dunns Hill) has much more information.

Sadly the monthly and annual reports do not have the wind gust data in the summary reports, so I’ll have to go through the detailed data for ferny creek.

But I did find the wind roses. I knew they had them. Now all I need is a wind rose that shows the average over the day and peak gust winds to input into the house design.

Having a house that faces to the north east means we are somewhat sheltered from the strong southwesterly winds. But we do still bear the brunt of the northerlies and those winds can be fierce. Being in the top third of the mountain means we are much more exposed, but the medium forest tree cover provides some protection, though it also provides many branches to fall from the sky.

I guess we will need stronger windows as we want glass facing to the north to get the sun. Eaves will keep out the summer sun and provide some protection from the falling tree parts.