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Guest paul y

greenhouse advice please

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Guest paul y

hi everyone hope your all well? I am hoping to get some advice about greenhouses from those in the know!

glazing, what is the best material? I have a five year old son and I live in a rough area of Bristol, im worried that glass may cause an injury to my son or the teenagers may use it as target practice.

Is twin or triple wall polycarbonate any good? I have read its an excellent insulator, its light transmittance is as good as glass and its virtually unbreakable, but all of this is sales pitch, can you guys give me some real feedback, I have space for at least 12ft by 8ft, no real budget constraints.

ventilation and climate control,

I have been advised that cps are best grown in a cool house (as in heated to a minimum of 5 degress Celsius) thus allowing correct dormancy but preventing major freeze thaw cycles and also allowing me to grow a much wider range of plants, how costly can this be? I appreciate its dependant on lots of variables but in general is it worth it? I have access to loads of high end horticultural equipment due to previous employment, climate controlled extractor fans, hid lighting, humidifiers dehumidifiers, misters foggers light rails you name it is any of it useful?

Can anyone recommend a decent greenhouse company?

many thanks in advance paul

Edited by paul y

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Hi Paul, I've only ever used toughened glass as the main glazing, saving twin wall polycarbonate for secondary (removable) insulation. I think the toughened glass is about 4mm thick as opposed to the basic horticultural stuff which is 3mm thick. I think most good companies are using the toughened stuff these days. I understand that toughened is supposed to shatter like car windscreens if broken rather than break into jagged pieces.

You didn't say whether you're considering aluminium or cedar framed. My current GH, which is 12' x 8' cedar framed, came from Woodpecker Joinery in Staffordshire who I would recommend (with a slight caveat to make sure you check all the details thoroughly as I found that communication wasn't their strong point). Cedar framed are supposed to be easier to keep warm, so far I think I'd agree but what I did find is that it is much easier to fix things to because you can screw polycarb panels etc straight onto the frame. Previously I had 8' x 6' aluminium GH from Greenhouse People I think it was by Hercules. We bought that one because it had high eaves which we felt suited us better. There were no real complaints about it, just out-grew it.

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If I were you I would buy your frame from a aluminium stockholders and make your own frame . Then get all the bits else where . You can get secondhand glass for nothing if you beg and asked nicely . Costs are a fraction of what people are paying for a greenhouse today . The best thing you can make it anysize you want rather than being told what size you can have . I did this many years ago and never looked back .

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Hi Paul

what is it you intend growing.

if it is sarras and pings, utrics and heli's, then your requirements will be different from a setup for Neps etc.

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Hi Paul,

It's a good time to look for greenhouses for free or on the cheap .Gumtree and the like.

Normally would have to dismantle and take away .

I use normal greenhouse glass and my grandchildren who ages range from 2 through too 9 have never hurt themselves or any glass broken and they visit daily.

I am intrigued as to which 'rough area' of Bristol you live in...from a grower that has been growing in Bristol...and I donot mean the outskirts, for many years.( I live in Lockleaze)

Regards

Davy

Edited by Davy

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Guest paul y

hi everyone thanks for the replies, its helping to narrow my decision, i plan on growing anything that can handle our climate inside a greenhouse and outside in Belfast sinks, raised (and insulated) bog gardens, and big pots, i have a small terrarium inside which will soon be upgraded to a decent tent, and a south facing window sill which has served me well for cps the last few years.

in short im a plant fanatic oh and i live in knowle.

does anyone have any experience with twin wall polycarbonate greenhouses? ive been told they are strong and insulate much better than glass.

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Twin wall poly is better than glass and wood frame is better than aluminium. If your intending to heat the greenhouse to a decent temperature (min 10C+) you might want to consider a wooden frame with multiwall polycarbonate.

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As Manders has said polycarb is better in most ways than any type of glass.

With a little ingenuity you could clad a standard (glass free)aluminium frame with a multi wall polycarb say 16 or 25mm.

This would give better insulation than double glazing. Pay proper attention to fitting and weatherproofing and you will get long lasting results.

Another option:

No kind of single pane glass will give better insulation than even 4mm twin wall polycarb and whilst this can be used as a sole glass alternative, it is much better used as a secondary glazing inside the glass skin.

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I will be getting my first greenhouse this coming Spring, and i've opted for a Rion 8x12.

Besides the twinwall 4mm polycarbonate glazing, it has a unique sturdy plastic tubular frame which offers better insulation that flat Aluminium bar. I'm also considering pumping expanding foam into each section as it is assembled for even further insulation, but a test run assembly would be needed first so as to be sure there's no errors during final assembly with fast curing foam filled tubes.

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Guest paul y

the more thought I give this the more I realise (like a lot of garden kit) its better to build my own.

my uncle works at fountain timber so I may pay him a visit soon, 6 inch ten foot posts for the main frame, flat roof supported by 5 by 2 joists, I can use chunky batten to make a door and vents windows and im going to box in a huge extraction fan in the top corner for those hot days! clad the whole lot in 4mm twin or triple wall polycarbonate, and build benches straight off the inside of the frame.

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the more thought I give this the more I realise (like a lot of garden kit) its better to build my own.

my uncle works at fountain timber so I may pay him a visit soon, 6 inch ten foot posts for the main frame, flat roof supported by 5 by 2 joists, I can use chunky batten to make a door and vents windows and im going to box in a huge extraction fan in the top corner for those hot days! clad the whole lot in 4mm twin or triple wall polycarbonate, and build benches straight off the inside of the frame.

4mm is too flimsy and will blow away or cave in. You will need at least 10mm, trust me on this!

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pretty sure the larger the space between polycarb walls the better the insulation will be ,same with double glazing,thicker the better, as far as flat roofs go they do tend to suffer from leaks more,and if having to brush the snow off is not an issue to you the fact that they get dirty quick might be,25 degree pitch would be the minimum for a pitch roof in my opinion,most polycarb should be fitted a certain way round as it has UV protection on one side,this is important or it will go yellow and brittle quick,

Edited by corky

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Guest paul y

okay 10mm minimum polycarbonate cheers for that, thinking about it now should of been obvious! I was thinking of a quite decent pitch to the roof but I intend it to run from front to back (front of green house being higher than the back) not worried about snow In Bristol im 36 ad have seen no more than 3 inches in my life, its going to be a 8ft wide 10ft long 7ft tall made entirely of 6inch pressure treated timber, 4inch joists every 2 foot to support roof and the same for all the internal framing to support glazing and door frame etc, pretty much the same as my shed just polycarb clad not feather edged

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I built my own small, timber-framed lean-to greenhouse last summer and glazed it with 10mm twin-walled polycarbonate. It's 9'3" x 4'7" and over 6' high at its lowest point. I used treated 3" x 2" timber for the frame. I couldn't figure out a way to do the roof with polycarbonate so used corrugated PVC instead. (I am neither a competent carpenter nor an experienced DIYer.) I wasn't so much worried about retaining heat as providing shelter from the wind and rain. One advantage so far is that on cold nights condensation forms only on the outside of the plycarbonate panels leaving the inside walls dry, which means that algae and slime have no opportunity to develop.

As has already been pointed out, if you intend growing only Sarracenias, Venus Fly Traps and some sundews, then you don't need heating. Most of my plants have survived outdoors during the past three winters and I still have two containers of S. flava , S.leucophylla , D. muscipula and D. binata standing outside this winter.

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Guest paul y

thanks again for all the advice it really does help, im getting quotes now on the polycarb, different companies different advice, uv protection? fixtures and fittings, apparently its not such a good idea to screw it straight into the frame in single 9ft by 8ft panels? expansion contraction etc etc any advice on all of this? im not building a conservatory so a little expansion and contraction shouldn't hurt, any issues with a panel being fitted whole and screwed to a batten frame at every 2 foot?

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the expansion and contraction makes sense ,the larger the panel the more the panels will expand and contract,the problem is when they contract you will have gaps appear ,this might not bother you but when they expand this could damage the panels edges or start to buckle the panels ,unless an expansion gap is left between the boards,you can probably get a H section jointing piece to get over this by fitting the panels halfway into this section the boards can expand and contract and still be sealed.I mentioned about the UV protective side to the poly because all the poly i have fitted (conservatories) have had it,i think it protects the poly itself from breaking down and also in a conservatory situation stops carpets and the like discolouring ,but i don't know if the poly used for green houses has this UV protection

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Why do people use polycarb it as a short life span . If you do your research proper their are better products on the market that is twin and triple ply which will last a lot longer .

Second screws are no good for polycarb their are special fixings that will be waterproof as screws will let water in .

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how short a life span do you mean,and an example of other products would be useful i am sure,he is doing research he is asking this forums users

Edited by corky

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multiwall polycarb expands +-3mm per M.

The companies that supply the products will also supply all you need to fix it following good practice.

All polycarb comes with one side uv protection and a removable film to identify which face goes outside.

It is the same with any product, it has to be installed properly.

there are special expansion washers used to point fix and the snap down glazing bars have the appropriate seals and expansion allowances built in.

there is no problem with big sheets as long as the rules are followed. Use fixings for timber supported structures.

If you look at my thread http://www.cpukforum.com/forum/index.php?showtopic=45597&hl=

you will see how I have used polycarb, and if you see the pics of my temporary housing, you will see a timber carport with a 10mm roof.

Polycarb is easy to use lightweight strong and insulating, you could not possibly build the kind of structure you have in mind with glass. if you follow good practice it will last beyond the 10 year guarantee.

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polycarb is an old product . Their as always been longer lasting products on the market . It's down to the buyer to find what's on the market now I haven't looked into for many years . What's on offer today should last a lifetime if you do your research and buy the right product . If this is what you want . Some people are happy for it to last a few years .

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polycarb is an old product . Their as always been longer lasting products on the market . It's down to the buyer to find what's on the market now I haven't looked into for many years . What's on offer today should last a lifetime if you do your research and buy the right product . If this is what you want . Some people are happy for it to last a few years .

You keep saying this.

Do you actually have any useful information to share with us?

Maybe you could update everybody's knowledge with something positive!

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I bought all my twin wall polycarbonate panels (for internal GH insulation) from Liv Supplies, they've got plenty of options (different thickness, numbers of ply, fittings, guttering etc) and pdf docs you can download to see what's involved before you buy. They do a cut to measure service. I suppose other suppliers do to but my experience with Liv was good overall. They do recommend leaving a 5mm expansion gap which you'll need to factor into your design somehow, the same applies to the screw holes.

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LIV Supplies is the company I use also, the cut to measure service is excellent with no charge for waste and they also tape all the edges up with the proper tape and at no extra cost.

Cheapest I have found.

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