How to (Re) Skin A Polytunnel

Are you brand new to polytunnels? Perhaps you are just setting up your first tunnel? Or is it time to replace the plastic on your existing tunnel? Here are my top tips for when it comes time to (re) skin your polytunnel!

Our polytunnel was absolutely decimated by a storm this past winter. Most of the plastic cover was ripped apart and blown away by gale-force winds. The frame amazingly stayed mostly intact, though many of the frame’s clips and braces had slipped and required re-adjustment.

We took this opportunity to fix some of the features we were not happy with when we first skinned our tunnel. And also added some upgrades that we had been considering.

In this post, I will walk you through our thought process and preparation, as well as the big day. There will be top tips and lessons learned from our experience to help you with this important task!

Services available

If you live are fairly isolated or you think you will struggle to put up the tunnel yourself, you can hire the services of a company to erect your tunnel for you (or to come and assist you).

It might be worth considering this if you are putting up your first tunnel. Polytunnels are expensive, so any mistakes could prove very costly!

But, if you feel confident and well informed, don’t be afraid to do the job yourself!

Time of year

If you’re planning to skin a polytunnel, the first step is to plan when you’ll do it. Ideally, you need a calm, warm, still day. Aim for as little wind as possible to avoid your plastic cover flapping about or trying to take of as you’re lifting it over the frame. A warmer ambient temperature will help the plastic to relax a little as you pull it taught.

We have found that early Spring works best (end of March or early April here in Scotland). I would highly recommend having everything ready to go, whilst keeping a close eye on the weather forecast. Pick your day at relatively short notice so that you can be sure of the weather.

Repairs and upgrades

Once you have committed to re-skinning your existing tunnel, it’s time to take a look at your current set-up with a critical eye. What works well? What could be better? Is there anything new you would like to add? Be sure to give this plenty of thought.

We decided to add a ventilation panel on the north-facing side of the tunnel. We have seen temperatures top 45⁰C in there over summer, even with all the doors open. So we wanted the option to get more air flowing on really warm days.

Additionally, we chose to change the set up of the doors so that they open outwards instead of inwards. The main reason for this was just to maximise the usable space inside the tunnel.

Have a good look at your frame and batons. Can you reuse all of it? Does any of it need to be repaired or replaced? If you are making some changes or upgrades, do you already have any or all of the parts you need?

Get prepared

Spend some time putting together an itemised list of everything you will need. I would highly recommend running this past the customer services department of the company you are using, just to double check that you are on the right track. I really cannot recommend First Tunnels highly enough for their excellent customer service and communication!

Place your order well in advance and assemble as much as you possibly can of the framing. I would also advise assembling your doors in advance, too. Then you just need to hang them once you have skinned your polytunnel.

As you are nearing the big day, start pre-nailing your batons. This will make the task of securing the plastic cover SO MUCH easier.

Ensure the area around and within the tunnel is kept clear of rubbish and debris, to maintain safe and easy access.

And beg, borrow or hire a couple of long ladders. This will be handy on installation day, just in case the plastic cover gets stuck at any point as you are sliding it over the frame.

Recruit your village

Well in advance, send some feelers out to see whether any of your neighbours, friends and relations would be willing and able to lend a hand. The more hands, the better!

Once you have everything prepared, message any willing recruits again to let them know that you’ll be aiming to go ahead in the coming week or two, depending on the weather. Perhaps ask if there are any days that would be more convenient.

Then watch the weather forecast like a hawk!

As soon as a favourable day appears on the forecast, let everyone know that it’s go time! Advise them that it may be a long day. Make sure you have plenty of refreshments in stock to keep everyone nourished and hydrated. This time, I made a double batch of scones with some homemade strawberry jam.

On the day

When the big day finally arrives, double check that you have all the tools and equipment you need, ready to use. As a minimum:

• Hammer
• Spare nails
• Spare batons
• Drill
• Heavy duty rope, cut into sections long enough to go over the top of your frame
• Ground cover

We tried to get as much of the preparatory work done before our willing volunteers arrived. We didn’t want to take up too much of their time.

First Tunnels have some excellent instructional videos on their website, if you need some additional guidance before erecting your own tunnel. Unfortunately, I did not record us re-skinning our tunnel! But here are the steps that we took.

How to (Re) Skin Your Polytunnel

Lay a tarpaulin or other ground cover solution along the length of the tunnel, and open out your roll of plastic on this. You want to keep it clean and free of damage, so make sure you don’t walk over the plastic with shoes on!

Roll the leading edge of the plastic cover around a baton (you may need to use a series of batons for a longer tunnel). Lay the tail ends of your sections of rope on top, at intervals along the length of your tunnel. Try to space them evenly. Leave enough rope to tie it off around a second baton – see the diagram below. Sandwich a second baton on top and screw through the two batons to secure them. Tie the tail end of the rope securely to the leading end.

Throw the leading ends of the rope over the top of your tunnel frame.

Get your volunteers into position, and ask them to slowly and carefully pull on the rope to begin lifting the plastic cover. If you have enough people, have someone (perhaps yourself) overseeing the operation from an objective standpoint. You can make sure that the plastic cover is unfurling nicely and that it is being pulled up evenly.

Once the cover is over the frame, unscrew and remove the batons and sections of rope. Now station your volunteers around the tunnel to hold the cover in place.

Take your pre-nailed batons, and being pulling the plastic taught and sandwiching it with the batons against the base rails on your frame.

Take extra time around the doors to pleat the plastic neatly and fasten it tightly. You won’t easily be able to adjust the ends once they are done.

Finishing Touches

Once the plastic has been secured all the way around, go inside your tunnel and loosen the fastenings on your base rails, one at the time. Ask a volunteer to stand on the base rail to pull the plastic drum tight, while you tighten the fastenings back up again.

Hang your doors and install the drop bolts (or your choice of alternative fastenings). And you’re all done!