[DoubleDigger]

I am looking for some practical advice on Polytunnel width, based on the generic designs for a 'self-build' Tunnel as generally available by searching Google & the Web.

I have sourced my 63mm MDPE pipe & have just picked up 12 x 5' lengths of Scaffold pipe.  I intend to make use of 'board' along the bottom edge, with Debris Net up to about a metre high, & another run of batten to fix the polythene to.  I think I have the fixing sussed with batten & exhaust clamps, but, I can't for the life of me find any indication of the "width" of tunnel the standard advice of 6m lengths of "pipe" will give me when dropped onto the scaffold pipe. 

Most Sites suggest that the top of the hoop will (may ?) give me approx 8' of height - but no clue as to what the width of said tunnel will be ?  In truth, I can live with a little less than 8' of height - the lower it is the less obtrusive on the 'Ground' - but if anyone has a Tunnel built to the suggested design, hopefully they can confirm the width & I can make some calculations from there.

[mumofstig]

A 19ft length will span a 10ft wide tunnel giving a height at apex of about 8ft

quote taken from this site:
http://www.overthegardengate.net/UserPages/pp_view.asp?FName=polytunnel&Page=1

[DoubleDigger]

That just goes to prove, that sometimes you can't see for looking   

Thanks for that.

[grinling]

Will the debris netting keep it a bit cool?

[DoubleDigger]

Will the debris netting keep it a bit cool?

Scaffold poles are in, poly-pipe is over the poles & I am fine tuning the 'design'.  I want to try to get the best of both worlds in terms of multi-season use, so I want decent ventilation with the option to keep out drafts.

My two main 'growing beds' have 4'6" high, 8' wide "half hoops" of lighter weight poly-pipe with Debris net over the whole bed - that is there to deter Pigeons, Partridge, & Pheasants....as well as injurious insect pests.  I have various leafy & flowering brassicas, lettuce, Onion's, first early potatoes, herbs etc under the 'net' & despite the weather it is more akin to the Burmese jungle than an Allotment 'bed'.  If anything growth is a little "too" soft & rapid, so I am confident that stuff keeps the worst of the bad weather out.

Given the "stock" size of the Polythene cover, & the size of my tunnel, 7.3m long, 2.2m tall & 10' wide, I reckon I can fix the plastic with a batten at a meter ( or a little less) high both sides - as per the generic design for self builds promoted on various Web Sites & then have a 'curtain' of polythene able to be 'dropped' down over the 'mesh' for winter use, if needs be to keep the drafts out.  I'll have a timber fixing batten at ground level & another at 2' / 3' high, so even if the worst comes to the worst, I can always fix a "strip" of polythene over the mesh if the 'curtain' proves to be impractical.

.....or at least that is the plan

[DoubleDigger]

Picked up the timber, ordered the polythene & 'brackets' today.  Very 'poor' now......I hope it is worth it in the long run. Looks like being a £300 'build' all-in.  That's a lot of lettuce 

 

[DoubleDigger]

Polytunnel is coming along.  One thing I am learning to be wary of, is trying to get "commercially supplied" brackets & fittings for 60mm pipe to fit 63mm MDPE polypipe.

Most of the brackets can be "made to fit" with a little bloke'ish encouragement, but 'P' Clips, can not & neither, presumably, can 'Q's.

Fortunately the 'walls' of the pipe, as they are reinforced with alloy sheet, take decent sized screws, so it's not that difficult to work around.   

[Rangerkris]

Sounds like an interesting project any pictures would be good.