[MikeM]

I am considering construction options for a workshop (to replace the one I was forced to take down). The structure will be about 12-14 foot across, and about 30 foot long. If I go for a pole barn, then I would use 6*6, placed about 6 foot apart. The walls will be shiplap larch and the roof that bitumous corrigated stuff you get (coraline I think it's called).

[Fleecewife]

Our pole barn is taller but we used telegraph poles halved and they go in 3' at least (we are on rock so it was quite an excavation).  They are concreted in.
 
We used Coraline for some sheep shelters and it blew off, in ripped chunks, with the first big wind.
 

[lachlanandmarcus]

Im not sure if coraline is the same as Onduline which is bitumous corrugated board - we have it on our stables put up about 3 years ago and we are on top of a hill facing onto the Cairngorms and havent had any issues with it. However we did use sarking board (OSB) underneath it and it does not overhang the building and I think both of those are key - the wind cant get under it and rip it off! Its safer than tin if it does come off too, which is partly why we went for it.
So I wouldnt rule it out but it depends on design and whether you line with board underneath.

[MikeM]

thanks FW, that's about the depth I had in mind.
Lach, I'm not sure, but I think they may be the same thing. They look like each other, some places sell it as cora and some as ondu. I will bear what you both say about it on mind.

[ZacB]

Onduline is more heavy duty than Coroline. Very easy to use, pay attention to predominant wind direction and ensure fixings are spaced correctly should be just the job 
http://www.eroofs.co.uk/shop/dept.aspx?dept=74

[MikeM]

fantastic, thanks for that link.

[smallacre]

Hello MikeM we used Coraline pretty much the same as Onduline on all our barns we built, the highest is 4.6 metre high and into the wind we fixed a 6inch by 1 inch flashing board so it finishes about 12mm higher than the edge of sheet this stops any wind from getting under it and ripping it off its been on since 2010 and we have been very pleased with it and we are in an exposed position.
By the way we first though of pole barns then decided on these. note the flashing board at the top.

[Brucklay]

Sorry no info on poles but we used onduline on our goat shed roof - Aberdeenshire and very exposed - and 5 years on it's still there. As said it all to do with overlaps/pitch and over hangs -


http://www.onduline.co.uk/PDF/Onduline%20Fixing%20Guide.pdf - there a good guide

[HappyHippy]

What a posh looking goat shed Brucklay, did you build that yourself 
Fancy a holiday down in Lanarkshire ? 

That's such a nice photo too btw 

[Brucklay]

Well HH, I would love to take the credit but Allen built it originally but I did do all the re-cladding in larch after the goats ate through the exterior ply - a labour of love in 200mm boards and 50mm battons but I am pleased with it now - each pen has it's own door or stable door so I can muck out easily - now to start the large lean too on the back for my lambing shed - it will never end 

[Plantoid]

On all UK telegraph pole there is a ten foot horizintal mark on the pole , marked from the bottom  .
When I worked for BT  I had to do a pole climbing course as part of my life was to occasionally have to climb poles in all weathers.
 
For safety for a 15 stone man to climb the pole it was said that the ten foot mark should be level with a five foot 8 mans nose so the mark is to be 5 feet out the ground in reasonable soil . For peat they were only two feet or three out of the peatdepending on the type found in the ground  and for rock  only four feet in the ground providing the rock was heavily compacted with a rammer.
 
 Because of the length of your barn I reccommend the same depths on a 10 mtr pole for a decent blowing wind could easily push the barn over in the poles are shallower , perhaps half it if you cut the poles in half .
don't forget to treat the bottom end of any cuts and once the poles are inth ground treat the fist 18 inches above the ground with a quality preservative so that the dew point moisture does not make the poles rot any quicker than needed . ding this teat ment has seen BT poles reach over 11O yrs or more in age .( came across some in Harrogate that were 123 yrs old ) ...without it they last ten years or so but not much more if it is really wet around the base. 

[MikeM]

thanks plantoid. I ended up not going the pole barn route. I dug the 1st hole and before I'd got 2 foot down it was filling with water, it would seem the water table here was not that low down. So I'm putting down a concrete pad and building a stud work frame on that.