30ft span Lean to shed

[CJay]

Hello all,

I am currently looking to put up a 30x40 lean to shed on my existing building.

I am looking a clear span of 30 feet(mono pitch) to the uprights as I dont want uprights in the middle of the building

There was been some debate at home to the size of beam to use.

Some say 8x5 some say 10x6 some say even bigger all that I know is... they cant all be right!

So I am wonder if any of you guys have similar spanning lean to sheds to give me a ball park size.

The current portal frame shed we will be leaning too is built with 7x4 H beam.

This shed will be used for general storage btw.

Thanks

Chris

 

[multi power]

i would think 10x6 would be fine

 

[Walterp]

We've got a 30' x 60 monopitch and the frame is steel - do you want to know the steel size?

The purlins are rotting, by the way, 'cos the steel sheets were fixed along the wrong 'line' and failed to use dpc on the underside. But the steel is fine.

 

[CJay]

Yea the steel size would be handy to known. I have another 60x30 lean to shed but it uses steel trusses instead of one single beam although the truss is made from very light angle iron and I don't want to replicate it, it did manage to with stand 18" of snow lying on it during the recent bad weather so must be fit enough for it

 

[JNP]

I would say the biggest concern would be adding a further 30ft span onto a 178x102x19UB column. We wouldn't recommend or undertake such an extension, I assume your current building is a 30ft span portal frame /\ ?

Cost wise, using a mono-pitch requires larger steels so a complete new build 30x40 portal would only be slightly more but would be an option worth considering if you have the space.

 

[multi power]

we have 30ft lean to onto 50ft wide portal frame, all 10x6 at home n its a nice job

 

[CJay]

I would say the biggest concern would be adding a further 30ft span onto a 178x102x19UB column. We wouldn't recommend or undertake such an extension, I assume your current building is a 30ft span portal frame /\ ?

Cost wise, using a mono-pitch requires larger steels so a complete new build 30x40 portal would only be slightly more but would be an option worth considering if you have the space.

Yes the existing is a portal frame! Would it be better if we bolted another portal frame onto our existing building using the existing uprights ?

 

[JNP]

we have 30ft lean to onto 50ft wide portal frame, all 10x6 at home n its a nice job

What size post is on the outside of the 30ft lean to?

 

[multi power]

i think 10x6 as well , lean to box profile but main shed big 6

 

[JNP]

i think 10x6 as well , lean to box profile but main shed big 6

That's my point, your 30ft lean to has 10x6 columns on the outside where they are only supporting half of the 30ft. The OP has 7x4 columns which need to support the existing frame and the new one.

Yes the existing is a portal frame! Would it be better if we bolted another portal frame onto our existing building using the existing uprights ?

Yes, if you bought a new mono-pitch building and bolted (or welded) the columns together they would act as a compound columns (ie. work as 1 big 1) then you would be ok, but with the work involved with drilling the columns and sorting out the bases, you may find it better to put it up as a free standing building.

 

[multi power]

dad got some lads to put up a lean to but it cost more than they said, took too long etc, would have been just as cheap to put up a proper portal twice the size , not that there is anything wrong with a lean to

 

[JD7710]

I put a 30' lean too onto an exsisting 30' shed for someone 3 years ago, the exsisting apex shed had 203x133x25 legs the new build lean too was built from 203x133x30 rafters and new outside legs.

 

[CJay]

Certainly food for thought here. It's great to have access to no nonsense advice!

 

[Derrick Hughes]

I have one just short of 40 ft x 22ft bays on 10 x 5

 

[Tarw Coch]

We have a 60 x 30 lean to here off a dutch barn, put up long before we came here 30 years ago. The steel in the lean to is 8 x 4, the uprights for the barn are less, probably 6 x 4.

 

[CJay]

Think I might just put up a another portal frame building on each side of the existing shed. Going to be just a cheap to do.

 

[Penmoel]

We have a 30' leanto of a 60x30 on 7x4 uprights, the beams in the roof are 8x5 ontop of a 7x4 upright, been up 20 years or more no problems- so far anyway.