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srohara
21st Oct 2007, 10:43 PM
Hi all

I am wanting to replace a beam in the roof that covers my existing deck, i want to put in a beam that has a biggest possible span as i really dont want many supports. Preferably 1 post at each end. I just dont know what size beam to use.

The length of the roof is 4400mm,
width to the beam 2000mm
Total width of roof 2300mm
All the frame is 100 x 50mm Hardwood

Want to span 4400mm. Can anyone suggest a beam size and span length.

Regards
Scott
Pulse
21st Oct 2007, 10:53 PM
Photo would be great, framing manuals talk about Roof load width and rafter span and spacing etc..

Sometimes a photo is the best way to know we are all talking about the same things

Cheers
Pulse
srohara
22nd Oct 2007, 07:37 AM
Here are some pics of the roof
glock40sw
22nd Oct 2007, 08:30 AM
G'day.
I just ran your dimensions through the "Timber Solutions" Span software.
It shows a 125x38 unseasoned hardwood beam will do the job.This is to support a roof and ceiling. A post at each end with 1 in the centre.

Beam span to be 2200mm between posts.

Hope this helps.
srohara
22nd Oct 2007, 08:42 AM
Would i be able to use an LVL or I beam. how would they go semi exposed to the weather, or would the hardwood be best
glock40sw
22nd Oct 2007, 08:53 AM
No. The span of 2200mm between the posts will not allow it.

I Beams cannot be used for verandah heads.

I tried Gluelam 8 beam and it showed a 165x80mm would be needed.

Stick to Hardwood
pawnhead
22nd Oct 2007, 10:14 AM
According to this span table (http://www.mcintosh.co.nz/documents/10Australian%20Lintels%20and%20Roof%20Beams.pdf), a 320x65 GL8 will do that span in one go.

That's a big/heavy/expensive stick of timber though.
srohara
22nd Oct 2007, 03:21 PM
Could i get away with using a 145x45 tp or a 190x45tp ans span 2200mm
silentC
22nd Oct 2007, 03:32 PM
A 120x45 in F5 or F7 will span 2400 with a 1000 1/2 rafter span, which is what you've got, but you're right on the edge, so going up to 140x45 would be a good idea.

If you want to span the full width, an open web girder (can you even still get them? :- ) or a universal beam would do it but would be pricey.
pawnhead
22nd Oct 2007, 09:06 PM
You generally can't get 120x45 off the rack, so they'd probably be ripping down a 140 and charging you even more for the time involved.
srohara
24th Oct 2007, 08:09 PM
What size LVL or GL beam could i use to span 4400mm
silentC
25th Oct 2007, 10:31 AM
http://www.chhfuturebuild.com/uploads/Hyspan_SpanTables_Mch06.pdf
pharmaboy2
25th Oct 2007, 10:54 AM
hi, just stuck a 4400 beam, 600mm rafter spacings, 1.3m roof load width for verandah beam - supporting ceiling into hynes deign prog and got 200/45 LGL or 170/65 LGL to span that. It can be ordered in H3 treatment
Pulse
25th Oct 2007, 12:14 PM
Smorgon LiteSteel Beam LSB (http://http://www.smorgonsteel.com.au/lsb/features/group.cfm?GroupID=6) might help. They are light, and easier to work with than rolled steel sections.

Cheers
Pulse
srohara
26th Oct 2007, 10:56 PM
Ended up using a 240 x 63 LVL and encasing it in blue board
DvdHntr
29th Oct 2007, 04:40 PM
Ended up using a 240 x 63 LVL and encasing it in blue board

When spanning beams like that I would have preferred an LVL also. Probably would have gone for a 300x63 LVL though.
pawnhead
29th Oct 2007, 10:57 PM
Probably would have gone for a 300x63 LVL though.Why put in more than you have to?
According to the tables he's alright, and I'm sure there's plenty of margin before any failure. At least 2:1 I'd imagine, but probably a whole lot more than that.
DvdHntr
30th Oct 2007, 10:04 AM
Why put in more than you have to?
According to the tables he's alright, and I'm sure there's plenty of margin before any failure. At least 2:1 I'd imagine, but probably a whole lot more than that.

I just like to have very limited deflection over openings like that. Plus without the table that was my first guess. If I had a proper look at it and the 240 was less than 8mm deflection long term, I would have went for it.