Temporary Structures

[David Sparkes]

I'm really irritated; I've spent a couple of hours searching, read some really interesting threads, but haven't lit upon the Search terms that would have pulled up the information I want, yet I'm sure it was on this Forum (although I don't recall the section).

I am looking to replace a polytunnel, used mainly for parts storage. It's never been a total success. Although the initial installation was 'OK', every time the sheeting has had to be renewed it seems to be more and more difficult to get the sheeting tight, with the result it flaps in the wind, and wears out.

Perhaps my polytunnel ground works have never been deep enough, but it seems to me that the flapping plastic manages to draw some of the plastic out of the ground, which makes more material to flap in the wind.

Anyway, it's 15ft wide, 30 ft long, and 8.5 feet high, (say 5M x 10M x 3M).

What I recall reading, and thought to come back to, was a more square framed temporary steel structure, the important difference being the plastic was secured to the frame, rather than buried into the ground.

At the time I didn't compare size to size, or even compare the costing of a new structure against the (unsatisfactory) new polytunnel sheeting, but I do realise I may have to spend more money in pursuit of a better product. I have a vague recollection that I might have needed two to cover the full 30 ft.

Can anyone please recall threads that have covered this sort of gazebo(?) structure?
I think it was in the last 12 months.

Thanks.

[Ed Poore]

If you do it right then a poly tunnel can last for a long time. My parents have one and the first plastic lasted over 10 years. Had to be a still, warm and dry day (well as close as you can get in Wales).

Last year when they got it replaced they paid someone and did a damn good job. Of course slightly more expensive but I think it was £500ish all in. That did include the plastic and its a 20x8m tunnel so not small.

Could try and find out their details if you're interested?

[LiftedDisco]

Right... not likely to be easy to do over emails and forum posts but I will try to help...

I don't do polytunnels but do sell huge great tensioned fabric structures - things like the hangar over Concorde at Manchester Airport, various salt barns around the country and the most recent being a biomass storage shed at Liverpool Docks of 65m x 170m and measuring 36m to the apex!

No matter the size, tensioning things is relatively simple but will really depend on what you have on your poly covering...

I think that poly tunnels are normally poly-ethelyne which should give a service life of around 10 years as the plasticisers in the material are affected by UV and go brittle at the 9-10 year period which then means that any movement in the material results in splits and shredding.

Ideally, you need to have a pocket above ground level - we build ours off a concrete ring beam and then put box section through the pocket and use threaded rod that is resin anchored into the concrete ring beam. You then use nuts on the threaded rod to tension the box section within the pocket downwards - if you do this equally on each side you will pull the fabric taught over the structure.

When you talk about material being 'buried' or pulling out of the earth, I don't really know what the current set up looks like - perhaps you could post a photo? All I do know is that the system we use doesn't really need any attention after installation - we use PVC for our roof sails, offering a life expectancy of 25 years.

Hope this helps!

[LiftedDisco]

Photo of the Liverpool structure during build:

[simonr]

Impressive!

We have an impressive list of experts in diverse subjects on this forum!

At work there is a building which has a polymer roof, suspended over a frame made in two layers which are inflated. In part to tension it but also provide (a little) insulation. This was a temporary structure but now planning has been granted so they are enclosing it in a hard shelled warehouse and will dismantle the original building from the inside. I wonder what they'll do with the sheeting - there must be 1/3 Acre of it!

Si

[miketomcat]

https://www.dropbox.com/s/d8wz0ksinkenu2g/2012-10-24%2015.29.39.jpg?dl=0

This is our building at work it was shipped over from the state's and was built with 5 blokes and a land rover (pto winch). It's construction is similar to a polytunnel but the covering is pvc and tensioned as lifted disco discribed but the bolts go into part of the frame as we have a 90ft section on wheels so we can roll it back to get the boats in then it rolls back and is strapped down to anchors.

Mike

[Boydie]

"Temporary Structures" I once heard of a young professional "lady" who put her occupation on her tax return as "Demolition Expert" when questioned by the tax department on her expressed occupation she answered that she removed temporary erections.

[Disco-Ron]

Bezt one I've seen local to me id s car port.

or in reality. A scaffold frame wrapped in packaging cling film. .... as long as you don't do any grinding it could be quite effective. .. its pretty strong stuff in multiple layers.

[ballcock]

"Temporary Structures" I once heard of a young professional "lady" who put her occupation on her tax return as "Demolition Expert" when questioned by the tax department on her expressed occupation she answered that she removed temporary erections.

Great one that. Had me in stitches.