# Forum Home Renovation Pergolas, Gazebos, Strombellas & Rotundas  Roof Beam Span

## russall

Friends, 
I am building a small ground level deck on the front of my house and would really like to not have any posts in the middle of the deck.  This would mean I need to cover a single span of 5400. 
The roof beam will be supporting 1800mm of laserlite. 
My Span tables say I can use 190x45 seasoned MGP12, or 170x45 F17. 
Does that refer to TP or Hardwood? 
Also does anyone know what my options would be for using steel for the beam or to strengthen up the beam. 
My preferance would be to use Treated pine for the beam. 
Thanks for reading.

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## SilentButDeadly

MGP stands for Machine Graded Pine. Not necessarily treated though.  F17 is typically hardwood. 
And I'd be guessing your span tables are quite a long way out of date......to manage a single 5m roof span I have recently had a 240x63 F17 hardwood beam specified based on ratings supplied through MiTek.... 
Using steel you'd get that span with a much smaller dimension.....but I couldn't tell you what it would be....

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## russall

Thanks SBD for the MGP translation, kind of obvious, but I didn't know.  I'd say my tables are definatly a little out of date,
Cheers, 
Does anyone have any tables for C section steel?  I'm a real noob, is c section even the right stuff?

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## 2x4

http://www.scottmetals.com.au/purlins.html  in wooloongabba will be able to help

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## Pulse

Try Litesteel beam. They have span tables for download 
Cheers
Pulse

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## barney118

You havent mentioned the load width to be able to help. As far as cost is concerned you can get some pretty good LVL (laminated veneer lumber) that would probably do the job or a GLULAM (glued laminated beam). I downloaded a frre program from timber build http://www.timberbuilt.com.au/softwa...nit/index.html
or from timber solutions http://www.timber.org.au/menu.asp?id=141
The beauty of using this stuff is its straight as steel and carries bigger spans. I take it you are going to paint it vs staining.  
These programs are basically AUS STDS in liquid form :Biggrin thumb:  I would only consider steel if you were trying to reduce member size as other problems arise such a joining wood and steel etc.

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## SilentButDeadly

The only problem....well two problems....with LVL and the Glulam products is the price per lineal metre is on the high side (~$30 per metre for 240x63 LVL) but the dealbreaker is that they typically have poor resistance to weathering.....so they aren't ideal in relatively exposed situations such as this.

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## russall

The beam will be supporting 1800mm of laserlite, so I guess allowing for overhang to the gutters ect, they load with will be about 1700. 
Thanks for the links and Ideas, I'll check them all out.

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## barney118

SBD they are a little pricey, i paid $300 for a 240x65 glulam treated and primed 5.4m, and also a LVL 300x65x 4.8m I think for $150 which I used as a lintle to put my roof on without having to build walls just paint him up then cover with weatherboard. I am going to use the glulam now for the pool pergola and a decent span without posts.

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## intertd6

N3 wind speed ( 41 m/s )
roof load 10 kg/m2
roof load width- 1.9m
roof pitch- 8 degrees
rafter spacing- 0.6m to 1.2m
beam span 5.4m
= 220 X 35 Kiln dried hardwood beam
Regards inter

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## intertd6

thats F27 220 X 35 KDHWD
inter

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## 2x4

I'm guessinig the laserlite of 1800mm will be coming of the fascia to the veranda beam.
Would the roof load width not be 900mm?

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## intertd6

Just took it on 1800 / 2 plus 1000 overhang worst case = RLW of 1900
if it was 1800 / 2 plus 100 overhang = RLW 1000 then the beam would be 190 X 35 F27 KD HWD
inter

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## russall

I'm getting some great info here, thanks. 
So the load width takes into account weight shared by other beams, so in my instance there is 1800mm of laserlite shared between the beam and the facia, so the load on each would be 900m?

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## barned01

if everything is sturdy around the area, would not a 3mm RHS  galv steel be more than adequate (assuming you are supporting it's weight enough)? 
I ask this as when i did my pergola, that same spec beam was supporting quite a weighty steel structure including an unsecured middle post without any hint of bending or sagging and that was over 6 metres

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## russall

Okay, after some Google'ing I've worked out that RHS stands for Rolled hollow section, or Rectangular hollow section. 
What are the dimentions of the piece you talked about. Cheers

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