Thread: Building a Bali Gazebo (Hip Roof Help)

Hello all,

First of all great forum. It was really helpful for me when buiding a deck recently! I really would appreciate some advice and tips about hip roofs as im about to build my own Bali Gazebo. I suppose I call it a gazebo, but to clarify, it will be rectangular, not octagonal etc.

Basically,Im planning to build a 6m x 3.5m gazebo, primarily utilising treated pine, with the roof constructed with 12mm ply and asphalt shingles fitted, both for appearance and weight.

Im a little stuck at the moment regarding the rafters. Im planning for the rafters to be about 2400mm long, taking into acount a 400mm overhang on a 25-30deg pitch roof. I was intending to cut birdsmouths to sit the rafters on the beam.

All the literature seems to suggest I have to use 140c45 rafters, but i do prefer 90x45 for the overall athsetics and cant find any span data about 90x45's.

I wanted to ask if you feel that 90x45s would prove to be strong enough and not warp or bend over time? the shingle roof, with 12mm ply should weigh less than 18kg/sqm so its not like the roof is holding concrete tiles.

In addition, I was intending to run the rafters at 600mm centres meaning ill need 7 common rafters. I was also intending to put collar ties approximately 500mm down from the ridgeboard on the first and last rafter. Does adding a collar tie increase the total span of the rafter?

This turned out longer than I thought...so in summary the key questions are:

1) Will 90x45 rafters 2400 long be ok on a hip roof supporting 18kg/m2?

2) Will adding collar ties to 2-3 out of the 7 rafters provide sufficient strength/support?

*I was intending to use 140x45 on the hips and ridgeboard to ensure the strength overall is good

Your help is appreciated

Ben

PS - Blocklayer - Ive noticed you on the website....Have to say your website and calculators are bloody brilliant!