Polytunnel shape

[lottie dolly]

I have been thinking about 1,and wondered if the semi circle shape,and or the special poly cover film,that is responsible for it's internal environment,i am at present in the throws of playing with wood as the framework,as in trusses in 6 sections,all corners braced,twill be aprox 8x11ft,the plastic is the white version of the green readymade tunnels,from experience using on the grow barn initialy,and brand new,aprox 45 feet of it,thought it was well worth a try,this is instead of using the blue piping,this is another of my mad ideas,using what we have in store at the plot,am pleased with the 2 frames/trusses i have done,they strong,i thought i might as well put what we have into a tryout,then if succesefull,do a bigger one with the proper film on it,hence my question,i am after all a member of the nutters group

[veggiechicken]

Any photos Lottie?
Is the shape like a greenhouse rather than curved like a tunnel?

[lottie dolly]

think,8ft wide,6ft high,i have tried to replicate a sort of semi circle,it took a bit of working out on paper first,to a scale plan,the lower outside edges slope slightly inwards,the very top has a bit of a slope,flater than the standard green house,with another bit to join the other bits,it looks like a x between a 6 sided half circle,and a dutch grow house,it is quite strong,a bit heath Robinson mind,i have another 3 to screw together,plus they have to be all joined up in order to form the tunnel, will take some pics,when i have got a bit further on,and in progress,

[veggiechicken]

I saw this Lottie - not quite what you describe but maybe similar Ana White | Build a Barn Greenhouse | Free and Easy DIY Project and Furniture Plans

[marchogaeth]

I don't think the shape really affects the environment. That is more down to the ventilation and siting.

Polytunnels work by providing shelter from wind and increasing temperatures by limiting heat loss. In theory a curved surface has a higher volume to surface ration which should (I imagine) reduce heat loss compared with more cuboidal/hexagonal ones.

From the point of view of the person in the tunnel though, the actual fully curved ones can leave a lot to be desired because they are so low against the edges that they are awkward to work in even if you have plants that can cope with the limited head height! Much better to have at least straight sides IMO.

[lottie dolly]

similar,my bottom bit slope out and are longer,and the top roof sections flatter,a good project that,water collection is not so good,they have used good new stuff,mine is not,just want to see what happens with the winds and inside conditions,am trying to get a tunnel on the cheap,

[lottie dolly]

I don't think the shape really affects the environment. That is more down to the ventilation and siting.

Polytunnels work by providing shelter from wind and increasing temperatures by limiting heat loss. In theory a curved surface has a higher volume to surface ration which should (I imagine) reduce heat loss compared with more cuboidal/hexagonal ones.

From the point of view of the person in the tunnel though, the actual fully curved ones can leave a lot to be desired because they are so low against the edges that they are awkward to work in even if you have plants that can cope with the limited head height! Much better to have at least straight sides IMO.

Thankyou for that,i know what you mean about the low sides,my sides are just over 3 foot,they also slope inwards aprox 1ft,this seems to make the frame more stable to the winds,she hopes,so it will have useful planting space,tis only an experiment for bigger things next year,unless a one comes my way at the correct price,

[mothhawk]

I saw this Lottie - not quite what you describe but maybe similar Ana White | Build a Barn Greenhouse | Free and Easy DIY Project and Furniture Plans

Did you see this gal's power saw? WANT ONE!!!

[chris]

Me too!

[veggiechicken]

Blimey! I wouldn't want that saw anywhere near my gusset

[lottie dolly]

Did you see this gal's power saw? WANT ONE!!!

just had a look,that is one fancy chop saw,i like how it moves to finish the cut,the only ones we have just chop,that video has given me ideas,the but being,DH does not like me using it,

Have showed DH the link,he says YES his does the same as the video one,i am having a re-thought on the shape,maybe unscrew what i done and start again using gussets,not bracing bits of wood,

[lottie dolly]

here is the tunnel,i designed it,and DH put it together at my bidding,he would not let me use the machinery,bless him,i know the cover will not last long,but long enough for me to judge whether or not i want a bigger one,it is anchored down well,it can always have a net draped over it as life after plastic,as it is movable with peeps help,am concidering guttering along the sides,as i had some meatier timber on ready,the water will go straight into a butt each side,i am well pleased with it so far,

[rustylady]

You've done a fantastic job Lottie Dolly.

[VirginVegGrower]

WOW it's the shape of those fancy greenhouses that cost thousands. I think you two could start a business venture here.
So impressed

[veggiechicken]

That's fantastic Lottie - what a team you two are
I never imagined it would be quite so cleverly designed - ingenious
Wish I could "like" it more than once