Colorbond roof question

[Chumley]

The bloke from the supply shop said they would recommend a metal cutting disk rather than a normal disk, but said I should either use a nibbler or tinsnips as any heat can damage the coating. Tinsnips are good - might take more time, but it keeps me from being co-opted for weeding duty!

I figure if I set out the angles correctly and cut carefully, the offcut from the first sheet will match the last sheet to make the 6th triangle - and any subsequent cuts can define the opposite triangle --- strike, its hard to explain with just words -- I'm told I can get the sheets at any length - if my triangle is 1700 long from roof-centre to the middle of the wall edge, I can get several sheets of 1700 length, lay them out on the ground with the correct amount of overlapping, draw the first triangle starting from one edge with the base of the triangle on the edge closest to me, move sideways and draw another triangle with the base on the same edge adjacent to the first triangle, etc, etc -- the spaces between the triangles should be inverted triangles of the same size (stop laughing, it's as clear as mud to me).

Cheers,
Adam

[Big Shed]

The bloke from the supply shop said they would recommend a metal cutting disk rather than a normal disk, but said I should either use a nibbler or tinsnips as any heat can damage the coating. Tinsnips are good - might take more time, but it keeps me from being co-opted for weeding duty!

I figure if I set out the angles correctly and cut carefully, the offcut from the first sheet will match the last sheet to make the 6th triangle - and any subsequent cuts can define the opposite triangle --- strike, its hard to explain with just words -- I'm told I can get the sheets at any length - if my triangle is 1700 long from roof-centre to the middle of the wall edge, I can get several sheets of 1700 length, lay them out on the ground with the correct amount of overlapping, draw the first triangle starting from one edge with the base of the triangle on the edge closest to me, move sideways and draw another triangle with the base on the same edge adjacent to the first triangle, etc, etc -- the spaces between the triangles should be inverted triangles of the same size (stop laughing, it's as clear as mud to me).

Cheers,
Adam

When I built our house I worked with the roof plumber to cut down on costs. He said the same thing, no metal disks on Colorbond. We used tinsnips and my air nibbler. He was most impressed with the air nibbler.

I know where you are coming from with your inverted triangles, he did the same thing on all the hips ( and there are a few on this place!). We finished up with minimum off-cuts, was very impressed with his skills.

Here in Vic you need a roof plumber's certificate for your CoA, pretty sure that you don't need that in SA. Funny thing is I can put up a shed and not need a roof plumber's certificate, the wonderful ways of bureaucracy!

[Barry_White]

W

Here in Vic you need a roof plumber's certificate for your CoA, pretty sure that you don't need that in SA. Funny thing is I can put up a shed and not need a roof plumber's certificate, the wonderful ways of bureaucracy!

Big Shed

When work is done on a residence or garage that is part of a residence in NSW anyway it comes under the jurisdiction of the Dept of Fair Trading and work over a $1000 must be done by a licensed contractor.

If work is done on any type of building other than a residence they don't care who does it. They don't even care if you don't even know what you are doing.

[pawnhead]

If work is done on any type of building other than a residence they don't care who does it. They don't even care if you don't even know what you are doing.

Yeh, you could build a hundred storey skyscraper without a license, so long as it's not residential. You do have to know what you're doing if you want to get it past inspections though.

[Chumley]

Big Shed
If work is done on any type of building other than a residence they don't care who does it. They don't even care if you don't even know what you are doing.

That's good news for people like me - I mean I know what I'm doing up to a certain point, but I don't know much about some things (eg. span lengths, engineering concepts, etc) and on top of those things that I know I don't know, I don't know what it is that I don't know, so I can't ask.

[silentC]

I don't know much about some things (eg. span lengths ...

That's why God gave us span tables.

[Jacksin]

Chumley have you given any thought to using mini-orb as a covering?

It may look more olde-world on a gazebo than normal boring custom orb, like those old style window canopies that are becoming more fashionable.

[Chumley]

Hi Jack,
Can honestly say I've never heard of it - but now I have I'll check it out.
Thanks for the tip.
Cheers,
Adam

[Barry_White]

Hi Adam

Here is everything you wanted to know about Mini Orb and afraid to ask.

http://www.bluescopesteel.com.au/go/...saght-mini-orb

[Chumley]

Baz,
Gracias - quicker than me (although I am (nominally) at work)!

[Chumley]

Um, had a look - like the picture - got a bit lost in the techie stuff (maybe I should go back to bookcases!!). Have a couple of questions...

The info sheet says mini-orb is good for awnings but not for roofing - would you consider a gazebo ('bout 3m diameter, roof pitch only 20 deg) as a roof or an awning?

Spans - I figure a single span is like stonehenge, 2 posts, one rail? But what is an end span and what is internal span?

I do like the look of the mini-orb, if the tech side works out I'll use it.
Thanks,
Adam

[Barry_White]

Adam

I suppose technically the Gazebo has a roof but the reason the say it shouldn't be used as a roof is because of the low profile it would be impossible to waterproof it satisfactorily but in an earlier post you said you weren't too concerned about that because of the way you are fixing it.

The Custom Orb because of the higher profile would probably be harder to waterproof than the lower profile of the Mini Orb.

Because of the over all span you will need to put an intermediate batten to support the centre of the sheet the internal/end span (shown on the table) is going to be less than the 1500mm maximum shown in the table. To give it that bit extra strength you could use the .48BMT one.

That intermediate batten can be fixed to the rafters at the same level as your side supports attached to the rafters.

[Chumley]

Bazza (and Jack),
Thanks for the tips.
Cheers,
Adam

[Chumley]

I just noticed the colorbond info sheet says to "Avoid materials and liquids which can cause corrosion, such as lead and copper, green or CCA (Copper-Chrome-Arsenic) treated timber, uncoated steel supports, fertilisers, pesticides and abrasive cleaners..." I guess this means you shouldn't use colorbond with CCA treated pine. Does covering the pine with paint avoid the problem?