gcorgnet:wallop: We had a shade sail attached to one of our houses. The installers had a 6mm steel plate made up for the house connection. It was in a corner and the plate was then bolted to 2 or 3 rafters that meet at that point. The other ends were attached to telephone poles buried 3 - 4 metres in the ground. I remember them saying that they had seen rafters pulled off a house because the sail was attached incorrectly. The shade sails have a alot of force applied when it is windy. We have a different one currently that is attached to 4 120mm steel poles. Once it hailed and the weight on the sail bowed the poles. They went back in to shape was I got the melted hail off the sail. You are meant to take the sails down if it is going to hail or snow. A lot of poles bent out of shape down here last year when it snowed.
Wow, sounds like these shade sails are evil!
I guess the size would matter as well with bigger sails putting much bigger force, etc..
If you got that professionally installed, was it around Auckland and would you mind sharing the contact?
Down in Christchurch I'm afraid. They were pretty big sails, our current one is 6 x 6 and made of a solid pvc like shade material.