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C-Purlin Span Table?

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MrSurly

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I have Googled it to death and still not finding a simple span table for steel 'joists'.
I'm going to build a freestanding loft that will be a steel I-beam frame. I need to be able to compare the cost of materials for dimensional lumber vs steel using standard C-purlins as joists.

Labor is not an issue, welding, assembly not an issue, time is not an issue.
I already have the material of the frame (10" S25.4# beam) and the legs (4-1/2" oil well casing).
The joist span will be 14'.
I simply need to be able to compare wood to steel.

(Steel should save some headroom; slightly thinner flooring assembly)

Span tables for the wood indicate that for 40psf I would need SYP 2x8s on 12 OR 2x10s on 16. ( I don't actually know if the numbers here *assume* some standardized decking (plywood) weight value)
I would like to find out equivalent info regarding 4", 6" and 8" C-purlin (14ga).

My search so far has only found data sheets that provide engineering data on deflection factors, etc but not a simple span table. Any links?
 
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MrSurly

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WNYflyer said:
Some of the big companies, but probably many companies around with like products. Just compare depths, flange width, and return lip dimensions and of course gauges to compare products.



https://www.marinoware.com/



https://www.clarkdietrich.com/
Click to expand...



Thanks for the effort, but these are not actually the right sort of product.
I apologize for doing a poor job of explaining myself.

These are “engineered superJoist systems” and other proprietary-design component systems (at least from what I see) not the generic stuff that is just ‘dimensions and gauge’. I’m not actually shooting for info on the latest high tech super trick building-system component marketing stuff.
I’m looking for span tables that will relate to the “standard Cee purlin “ at my local steel building supplier.
(True, my local supplier was no real help on this)

This stuff
e88dc9ceda9ce34ace542cff9fd9fc26.jpg

Not specialty system stuff like this
7d41b3d4ac89682d8261fe0860703ebd.jpg


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MrSurly

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mcbane said:
Looks like Tapatalk deletes the first part of the web address. Try editing the web address to include the www.flexospan.com part.


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Click to expand...



This site will probably get me where I want to be, but I’m going to have to get out my laptop.
On mobile, it cries foul when I try to go go their spam table because it’s a pdf.
After I git back to the house I’ll try it on the LT


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meboatermike

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The 1st link mcbane gave loads right up for me as a pdf file -- but I am not on a laptop, (you just need Acrobat Reader or some other pdf reader).
 
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MrSurly

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My mobile is sketchy with pdfs but the laptop went right there. The info in the chart indicates 6x2.5 cpurlin at a 14' span is rated at 169#lf.
On another page a 'snow load' sample provides that if I need say 40#psf then I would do *Snow load (lbs/sq ft) x purlin spacing (ft) = allowable load/linear foot of purlin*
or 40x2= 80pLf rating needed.

So, if I read that correctly, using 6x2.5 C on 2' ctrs would be over-building (over 80psf).

So I could use 4' ctrs to meet 40psf but Im not real comfy with that idea.
I rather use more of a smaller purlin, I think.
I'm still looking for a rating for 4"

I'm considering a single layer of 4x8 tongue & groove subflooring ply... maybe 23/32 OSB or the same size 'Plytanium'. Any thoughts? Too light? This is only loft/light storage area purposes
 
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Yelllow Scout II

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Try scafco.com and look around at the tech library, not much for roof purlins but they do have charts on floor joist that should get you close?
The floor joists start at page 51 in this guide, ssma-technical-guide-with-sfs they also detail out what bridging you would most likely need. I have not posted anything before so I can not include any links

Our company does steel stud framing and use them for most of our projects.
 
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MrSurly

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I found another table that includes 4x2 (14g) that indicates an 85#plf rating.... Which I *think* means that if I used the 4" at 2' ctrs, that they would provide just over 40#psf.

I hope I got that right.

Here's what I think I learned:

(21) 2x8 syp on 12" = $273 40#
(16) 2x10 syp on 16" =$272 40#

(11) 4x2.0 C purlin on 24" =$226 40#
(11) 6x2.5 C purlin on 24" = $306 80#
 
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MrSurly

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Yelllow Scout II said:
Try scafco.com and look around at the tech library, not much for roof purlins but they do have charts on floor joist that should get you close?
The floor joists start at page 51 in this guide, ssma-technical-guide-with-sfs they also detail out what bridging you would most likely need. I have not posted anything before so I can not include any links

Our company does steel stud framing and use them for most of our projects.
Click to expand...
Thanks for this! there is a ton of info there. I haven't read into it yet, but it looks like a trove of info.
The link to the SSMA book
 
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My Old Tools

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MrSurly said:
Agreed. I'm thinking of using strips of 14ga 3/4 strap bridging the bottom of the purlins say, 4' apart tacked to each purlin. Sound reasonable?
Click to expand...

Mine were installed on 16" centers, 20' span. I topped them with 5/8" OSB screwed down. When I started loading stuff on the floor, they started to twist, so I installed a 2x2x1/8" angle iron bolted to the bottom of each one at the 10' line. It stiffened up nicely.
 
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alexb2000

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My friend has a mezzanine with 10" C-purlins on 1' centers spanning 20' and topped with screwed down 1-1/8" T&G. The bottom has 2" wide by 1/4" flat bar strapping in two rows each ~3' from the centerline welded to the bottom on every purlin. He stores engine blocks, heads, body sheetmetal, etc. up there. LOTS of weight and no problems over 20 years. Just a point of reference.
 
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MrSurly

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Thanks for the info. That sounds similar to my plan but ill likely use a lighter gauge strap (it's in tension i think)
I finally got the I-beams up and hoping to get purlins up there quickly.


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