# Forum Home Renovation Pergolas, Gazebos, Strombellas & Rotundas  Carport/Pergola in steel... span??

## dastrix

Hi All 
Can anyone assist in determining the sizes required for my span? 
4meter width, 6.5meter length.  
Wanted to use 90x90 steel RHS posts, and wanted to use RHS beams and rafters. All welded/bolted. Can anyone assist in span tables for RHS steel? 
Thanks!

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## SilentButDeadly

You'd be better off using 150mm C section for the beams and rafters...and you'd only need outside beams (joining each post) with one (or perhaps two) run across the width of the structure and then roofed with Spanline sheeting...assuming it's not a pitched roof design you were looking for. 
Span tables for all this are available on the Onesteel or Lysaght websites

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## dastrix

Want to avoid C section, birds love to sit up there and @@@@ everywhere  :Wink:  Dont want anywhere for them to sit 
So, based on 6.5x4 you're saying 4 posts, 4 beams and 2 rafters only? 
I saw span tables for C section, but nothing for RHS, hence the question

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## SilentButDeadly

> I saw span tables for C section, but nothing for RHS...

  Which in itself might tell you something.... :Wink 1:  
C section is very easy to fit flashing to.  This'll stop the birds...

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## SlowMick

At that makes concealing cables and air lines much easier... :Biggrin:

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## dastrix

> Which in itself might tell you something.... 
> C section is very easy to fit flashing to.  This'll stop the birds...

  yeah id rather not have C section, thank you though  :Smilie:

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## dastrix

Can anyone confirm if these specs are suitable for the spans? 
6m long, 4 meters wide. 
We will using 4 posts, 100 x 100 in 4mm RHS steel. Our posts will be set back from the edges 350mm. 
Beams to be 150x50x3mm RHS steel. 
This is the area, the roof will fall into the existing gutter (replacing it with a Quad as its overkill) . We must remain off the brick wall, but can attach the structure to the steel garage. Its made out of C section gal steel. Quite light spec though   
We want this kinda look

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## ralph1malph

Hi Mate,
I am about to start something eerily similar. :brava:  
I couldn't find or interpret span tables for steel either.
I ended up asking a builder mate of mine (proper registered builder btw) to help out. He said he used a combination of timber tables and approved timber plans to calculate loads and factors then down converted to steel. Turns out what he calculated was very similar to what he would have guessed had he just gone by experience in the trade and having 'done a few'. 
Anyways, I digress. :Roll Eyes (Sarcastic):  
I am using very similar steel to yourself.
4 post pergola, 6x4 with two beams along the 6m. 4m insulated panel for roof (no rafters), 3m high with 3 or 4 degree pitch.
4 posts 75x75x4000 4mm RHS. 400mmx800mm hole with 100mm corbel (a lot of concrete).
2 beams 150x75x6000 4mm RHS. I'd pref to use 75 beams to match posts but supplier does not stock 75. All gal. 
I don't yet know whether to butt weld the beams onto the end of the posts or to check and weld/bolt. Anyone any advice? I'll probably check and weld/bolt. 
My mate assures me I'll get plans approved and the build certified. I too am not using c section for the same reason. 
Hope this helps 
Ralph

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## dastrix

> Hi Mate,
> I am about to start something eerily similar. 
> I couldn't find or interpret span tables for steel either.
> I ended up asking a builder mate of mine (proper registered builder btw) to help out. He said he used a combination of timber tables and approved timber plans to calculate loads and factors then down converted to steel. Turns out what he calculated was very similar to what he would have guessed had he just gone by experience in the trade and having 'done a few'. 
> Anyways, I digress. 
> I am using very similar steel to yourself.
> 4 post pergola, 6x4 with two beams along the 6m. 4m insulated panel for roof (no rafters), 3m high with 3 or 4 degree pitch.
> 4 posts 75x75x4000 4mm RHS. 400mmx800mm hole with 100mm corbel (a lot of concrete).
> 2 beams 150x75x6000 4mm RHS. I'd pref to use 75 beams to match posts but supplier does not stock 75. All gal. 
> ...

  Hey Ralph 
So your using 150x75x4mm for all your roof essentially but concreting in your posts rather deep. I wonder if bolting/chemset my posts will be OK. Ill brace the structure against my gal shed. 
My posts will be notched, so the beam will sit inside/on the posts.

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## dastrix

> Hey Ralph 
> So your using 150x75x4mm for all your roof essentially but concreting in your posts rather deep. I wonder if bolting/chemset my posts will be OK. Ill brace the structure against my gal shed. 
> My posts will be notched, so the beam will sit inside/on the posts.

  Going with this:  Boxspan® Steel Beams 
250x50 beams, 150x50 rafters, bolted 90x90 GAL posts. Comes with span tables etc and its alot lighter!

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## ralph1malph

> Hey Ralph 
> So your using 150x75x4mm for all your roof essentially but concreting in your posts rather deep. I wonder if bolting/chemset my posts will be OK. Ill brace the structure against my gal shed. 
> My posts will be notched, so the beam will sit inside/on the posts.

  Nearly, my supplier only has 150x50x4 so I'll be using that.
I dunno about chemset or bolts. The thing with free standing structure is _up force_, rather than down pressure. 
I am told, this means a lot of deep concrete. 
As you intend to brace, I am unsure. 
Ralph

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## dastrix

Hi Ralph hows yours going? 
Im nearlly done, just need electrical (this monday)  ceiling in cedar and then finally the limestone pavers....

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## AutoX

That's looking really good. Can I ask - does the roof fall to use the garage gutter as in you previous post. It might just be the photo but it looks like it falls away?
Cheers 
Sent from my GT-S7500T using Tapatalk 2

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## dastrix

> That's looking really good. Can I ask - does the roof fall to use the garage gutter as in you previous post. It might just be the photo but it looks like it falls away?
> Cheers 
> Sent from my GT-S7500T using Tapatalk 2

  The carport roof falls towards the person taking the photo  :Smilie:  you can see the gutter... 
The pavers are going down tomorrow and the cedar roof next week, the electrical is all done with some in ceiling speakers for entertainment :P

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## Fuff

I must say I think you are using material that is too heavy in both size & wall thickness.  I work for a garage company, for structure like this we would use 75x75x2.5 posts & C 150 x 1.9 roof rafters with a C150 x 2.4 edge beams.  This would meet all engineering codes for terrain cat 2 region A.  Be careful as building regs require any roof area over 10m2 needs building permit & engineering computations with engineers sign off.  Good luck tho!!!

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## dastrix

So managed to get the ceiling up on the weekend, just used R2 batts and installed 3 LED downlights on dimer, Clipsal motion sensor and 2 x KRIX Atmospheric AS speakers, which pipe back to a Audio receiver so we can play music using our mobile phones  :Wink:  
The ceiling has 1 coat both sides of Sikkens Cetol 7 plus, but we'll do another 2 coats on the under side 
Paving is 30mm limestone pavers, just ran a few short so we'll finish that up shortly and seal it. So far cost is under $9500

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## ralph1malph

> Hi Ralph hows yours going?

  Hi, Unfortunately, I have been away with work so ground to a stop until yesterday! 
I also changed my plans and as a result engaged an architect and  engineer to draw plans and footings suitable for council submission. I  incorporated a small verandah/deck with the pergola so I can build all  with one set of footings.
I was surprised that the engineer said I couldn't span more than 3.7m  with 150x50 so insisted on another post. In good news though, I am able  to attach the verandah deck to the house using a pole plate/ledger so  that will save me heaps.
I have been digging footings like crazy, as they are to be 900x450! In  other good news, I am able to span the roof in 50mm insulated down from  75 so a real cost saving there too!
Hoping to get a certifier to approve the footings soon so I can proceed with concrete pour!
Maybe some pics to come! 
Cheers
Ralph

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