joining greenhouses

[MyWifesBrassicas]

I've bodged all sort of stuff together over the years - secondhand, new built, wood, glass ,stone etc - as long as the foundations in are adequate to the weight, and level then the rest is more a matter of commonsense and taking your time (+ a second pair of hands if its a big bit) - wood and aluminum are easiest, because you cut drill and bend them with home tools - glass is a p.i.a. to work with - I have shattered double-glazed units trying to re-use them - my preference is triple wall poly-carbonate instead of glass, but it is dear - another see-through option is clear corrugated roofing sheets, which you can mix with the same profile bitumen sheets say, if you are in a windy spot and meed to get extra strength on an edge - these sheets bend easily across their width, so an arched roof is easy - try google for inspiration.

Finally the last critical point is "do you need a roof that doesn't let in the rain?" - if you do then joining two structures needs some thought - my advice would be, if you are unsure about roofs, is to ask around and find someone local who has done building work professionally explain the problem to them and listen to their advice - if you offer them £20 and a free lunch they might even give you a hand for an hour on a Sunday say.

happy to answer questions if you want some one to bounce thoughts off - pm me and I'll drop you my phone number

thank you Nick, great advice.
I might do that

[nickdub]

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I think the porch area could be a bridging gap between the two greenhouses in close proximity, say 5-6 ft or so and I can attach a few polycarbonate sheets over the top and back.
Alternatively, I could utilise the third green house for a T-shaped somehow or just make the porch T-piece and have each greenhouse on either side ??

how windy a site is it ? - plastic sheets of all sorts are brilliant but they do act like kites - I built some footings for a large poly-tunnel 2 years - a small wall - the site slopes - but before i put up the frame I knocked some 4' lengths of scrap aluminum angle I had into the ground and drilled and bolted trough into the wall than added some metal banding to tie the galvanized tunnel frame down with - it blows a hoouly up here on the hill some nights -I've got too old to be chasing stuff around the fields.

[MyWifesBrassicas]

how windy a site is it ? - plastic sheets of all sorts are brilliant but they do act like kites - I built some footings for a large poly-tunnel 2 years - a small wall - the site slopes - but before i put up the frame I knocked some 4' lengths of scrap aluminum angle I had into the ground and drilled and bolted trough into the wall than added some metal banding to tie the galvanized tunnel frame down with - it blows a hoouly up here on the hill some nights -I've got too old to be chasing stuff around the fields.

It can get fairly windy but my allotment is surrounded on all sides by housing, no hills unfortunately bit of an urban concrete jungle
I have some 10ft aluminum poles and 8ft 3x3' treated timber i could use to assist securing the poly sheets. It doesn't have to be watertight, just somewhere to shelter or rest for a bit, have a cuppa and maybe a bit of storage.

[nickdub]

Be me I'd look at use the aluminum bars as cross pieces perhaps to go from one side to another - the other thing which is cheap is roofing batten from the builders' merchants comes in 4m lengths from memory - easy enough to bring back on the top of a car if you want to fetch it - I stick some ranch paint on it use it 'short width up' for roofing with polycarb sheets, as you just drill down through the sheets from above - get a long screw with a metal then rubber washer (tap ones will do) and using a cordless drill just whop it in - not too tight adjust the clutch up to weak

If you go down this route check the "mushroom fixing" guidelines on a Polycarb sheet manufacturer's website for details on gaps - got to allow for thermal expansion and contraction as it moves a lot more than glass does when its warmed by the sum.

[MyWifesBrassicas]

Be me I'd look at use the aluminum bars as cross pieces perhaps to go from one side to another - the other thing which is cheap is roofing batten from the builders' merchants comes in 4m lengths from memory - easy enough to bring back on the top of a car if you want to fetch it - I stick some ranch paint on it use it 'short width up' for roofing with polycarb sheets, as you just drill down through the sheets from above - get a long screw with a metal then rubber washer (tap ones will do) and using a cordless drill just whop it in - not too tight adjust the clutch up to weak

If you go down this route check the "mushroom fixing" guidelines on a Polycarb sheet manufacturer's website for details on gaps - got to allow for thermal expansion and contraction as it moves a lot more than glass does when its warmed by the sum.

Wonderful.
Food for thought, thank you very much.

[nickdub]

Wonderful.
Food for thought, thank you very much.

no worries - you would not believe how many wrong ways I've tried when doing "make do and mend " building to hit on methods which are both simple and durable

BTW for anyone-else in a similar state of trying to produce a £1000 building for £75 plus some hard work always have a trawl around old stuff on Ebay or wherever a - an extra greenhouse with most of the glass gone can be had for £20 and give enough spare aluminum stock to help fix up another 2 - or sometimes people sell off old conservatories when they are having a new one put in - if you get one with polcarb sheets that are being disposed of, then the world's your lobster, in terms of what you can re-use it for when self building.