Farm buildings - 24 foot bays

crashbox

Member
Livestock Farmer
Anyone built a portal frame with 24 foot bays?

What purlins were used, and what spacings?

I know that 9x3 timber is available in 24ft lengths. I want to mix 24ft and 20ft bays to run across the face of an existing building, don't want a big post right in the middle of the bay!

TIA
 

robs1

Member
Anyone built a portal frame with 24 foot bays?

What purlins were used, and what spacings?

I know that 9x3 timber is available in 24ft lengths. I want to mix 24ft and 20ft bays to run across the face of an existing building, don't want a big post right in the middle of the bay!

TIA
Wouldnt use a timber outlines that long steel much better and can be made any length you want, you could also use some steel between uprights to fix the portal frame too so all the roof bays are the same but the legs where you want them iyswim
 
Would say if using timber purlins at 24ft, longer cleats should be used to reduce actual unsupported span of timber.
Prob cost more in delivery as wouldn’t be able to stack as easy on trailer unless they were bolted on/welded on to frame at site.
 

HatsOff

Member
Mixed Farmer
That's quite a long span. May need to go to steel purlins (Metsec etc) - as robs1 said these can be much longer and run over multiple rafters. The longer you get the more sensitive things get to snow/wind loading.

But... 24ft is definitely possible just needs the shed designer/structural engineer to plan it out.
 

glasshouse

Member
Location
lothians
Anyone built a portal frame with 24 foot bays?

What purlins were used, and what spacings?

I know that 9x3 timber is available in 24ft lengths. I want to mix 24ft and 20ft bays to run across the face of an existing building, don't want a big post right in the middle of the bay!

TIA
I built a shed with 26ft bays
30yr ago
 

Will 1594

Member
Arable Farmer

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8m bays are pretty standard on industrial buildings now, some going to 9m bays.
This one we recently did is 8m bays, 14m to the eaves and 20m each span. Central posts are every other, so 16m spacings. Everything is doable..

verda300.jpg
 

bluebell

Member
dare i ask about snow loading on the roof? i remember few years back seeing horrendous pictures of steelframed buildings both industrial and agricultural in this country most in the north that had collapsed because of the weight of snow building up on the roof?
 
dare i ask about snow loading on the roof? i remember few years back seeing horrendous pictures of steel framed buildings both industrial and agricultural in this country most in the north that had collapsed because of the weight of snow building up on the roof?

Thank is why calculations are so important, you should always confirm that you have site specific calcs for any project. Ask to see them.
 

LIVE - DEFRA SFI Janet Hughes “ask me anything” 19:00-20:00 20th September (Today)

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Hello, I’m Janet Hughes. I’m the Programme Director for the Future Farming and Countryside Programme in Defra – the programme that’s phasing out the Common Agricultural Policy and introducing new schemes and services for farmers.



Today (20 September) between 7pm-8pm, I and some of my colleagues will be answering your questions about our work including the Sustainable Farming Incentive, Farming in Protected Landscapes, and our test and trials.



We’ll try to answer at least 15 of your top voted questions, so please vote on the questions you’d most like me to answer.



You can read more about our Future Farming policy on our blog.



I’ve answered some of your questions previously: you can watch the videos on...
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