Allotment Gardening Advice Help Chat

Chatting => Design and Construction => Topic started by: brownp on April 29, 2018, 14:26

Title: Polytunnel cover issue
Post by: brownp on April 29, 2018, 14:26
I’m hoping someone might be able to offer some advice on tightening a polytunnel cover.
I recently constructed a new polytunnel.
It is a budget type from crocodile trading - 3.5 m x 4 m.
The frame seems quite strong and I reinforced it by concreting threaded bars into the floor , anchoring each corner to the floor. The frame seems quite sturdy.
The issue came when I put the cover on....it is one of the green, woven types - pre shaped etc.
When I put the frame in, I dug a trench around the perimeter and back filled it as I’d seen in youtube videos etc.
The problem is that the cover wasn’t deep enough to properly bury....I don't think that it has enough soil on it to keep the tension and I have found that the cover is loose and large pools of water are gathering after rain which will eventually ruin the cover.....
Does anyone have any suggestions of how to restore tension on the cover?
Thanks in advance..
Phil
Title: Re: Polytunnel cover issue
Post by: Toosje on April 29, 2018, 16:51
If it is woven: could you maybe use pegs (the ones you would normally use for a tent) to tighten the net to te sides?

I mean the thin ones, not the ones shaped as a corner or the thick plastic ones. (The left one on the picture)

Maybe the quality doesn't agree with this method.. Could you then use larger stones to keep it further down? I think that won't keep as well and you will be adjusting through the season.
Title: Re: Polytunnel cover issue
Post by: rowlandwells on April 29, 2018, 18:34
having put up a few tunnels in my time I to used to trench my poly sheeting in the ground drum tight  I bought one of those poly tunnels like yours for the allotment not put it up yet

so how to tighten your poly sheet well when i replace my polysheeting on my 20ft tunnel up the house im going to fit boards round the tunnel using U clips and P clips on the hoops then fix the polysheet to the boards then if i need to tighted the sheet all i do is undo the U/P clips and pull the sheeting down because the polysheet must be drum tight

hope this advise mite give you some idear how to overcome the problem good luck RW
Title: Re: Polytunnel cover issue
Post by: Nikkithefoot on April 29, 2018, 19:49
I don't think that type of polytunnel is meant to be drum tight like a polytunnel from say First Tunnels
Title: Re: Polytunnel cover issue
Post by: grinling on April 29, 2018, 21:50
Had a look at the website and it looks like it cannot be dug in unlike  a polytunnel  using polytunnel sheeting.
Anchorage on the site looks a lot like camping spikes and round discs. Paving slabs might help, but in very high wind damage might occur.
Title: Re: Polytunnel cover issue
Post by: rowlandwells on April 30, 2018, 08:57
I think your rite it doesn't have to be as tight as the commercial type tunnels like ours but it still needs to be reasonable tight and anchored to the ground because strong winds will lift it out the ground and the wind will damage the poly sheet I know this from experience

when I put my green tunnel up I'm going to brace the hoops and anchor the sheeting but I think it will be a good idea to remove the cover overwinter because the poly sheeting mite last longer not exposed to the elements

anyway I'm not in the business to try to tell anyone  how to suck eggs but from past experience in erecting poly tunnels to hopefully pass on some advise once again good luck with your tunnel
Title: Re: Polytunnel cover issue
Post by: sunshineband on April 30, 2018, 09:09
I have one of those exact polytunnels and there was enough cover length for it to be trenched in. It has stood up to gales on our very windy site ... so far, she says quietly.
It is difficult to get the cover as tight as one of those white ones and ours does rattle a bit in the wind. (Having enough hot spot tape on the frame helps stop wear as a result of this)

If yours is too short, brownp, then perhaps contact the supplier and talk to them about it. Paving slabs may be not be enough to do the job.
Title: Re: Polytunnel cover issue
Post by: ghost61 on April 30, 2018, 18:09
I agree with Sunshineband.  This happened to me with my first polytunnel.  I took photos and was sent a replacement cover that fits wonderfully and was trenched in.  It still sagged at the top, though because there was no beam at the apex of the curve going the full length, so we still got puddles of rain.  The solution?  A thick bamboo cane (made up of two cable tied together) and cabled tied to the steel frame, and voila no more puddles.
Title: Re: Polytunnel cover issue
Post by: Plot 1 Problems on April 30, 2018, 22:14
Exactly what I did with my old tunnel Ghost, highly effective too!