Hi. I recently found the following article which shows how to build a cheap and durable do it yourself poly tunnel (click here). I have bought some poly pipe and intend putting up a netted tunnel using the same method later in the year. I have created a small spreadsheet which will calculate a couple of things for you if you decide it’s something you want to do and want some help on the numbers as I did. Send me an email and I will let you have a copy unless I find out how to attach it to this web site in which case I will add it to this post as something you can download directly.
Good news. I have figured out how to attach it – Click this link to download the calculator – Polytunnel Calculator
Hope that helps – Steve M
Old Park Farm Garden Holders Association 