Can we talk greenhouse ?

[robo]

i have used a lot of twin wall pollycarb on my greenhouse its been on about 15 years now with no problems, have a look round all the upvc window company's in your area you might pick up some mis measured windows cheap with a little bit of "making it fit" you would soon have a maintenance free greenhouse, on the ventilation side have you seen the solar extraction roof fans they may well be what you need

[Ricard with an H]

I've never seen a greenhouse or any type of house glazed with polycarbonate though I did see a glass double glazed conservatory with a twin-wall polycarbonate roof and whilst it seems a good idea for a green house it seems wrong on the roof of a conventionally double glazed conservatory.

I'm not going to use horticultural glass, I often wondered about building regs that specify toughened glass up to a certain hight in houses and conservatories yet greenhouses are glazed in that very thin horticultural glass.

Am I missing something ?

May the rules have changed in recent years, i'd like to think I can have a slight mishap without slicing myself in two or getting an eye-full.

[PLUMPUDDING]

Just had a thought, my conservatory has twin walled polycarbonate in the roof and it is tinted with a very light brown for shading. It still gets quite hot in summer, but not so bad as untinted. They use polycarbonate as it is virtually unbreakable and shatterproof. That might help with your shading problem. You can get large sheets of it too and it is so much easier to handle than large panes of glass.

I think the thin glass in greenhouses is to provide the optimum light transmission, but my greenhouse is fitted with safety glass as it is next to a path and I don't want anyone to get injured if they trip and fall against it and I haven't noticed any light reduction .

[Ricard with an H]

Just had a thought, my conservatory has twin walled polycarbonate in the roof and it is tinted with a very light brown for shading.

Ahh-OK, so, using twin-wall polycarbonate on conservatory roofs is possibly to make the whole task easier because lifting and fitting the glass double glazing on my conservatory would be difficult.

Conventionally glazed conservatories use a standard sized glazing piece that overlaps the one below. With polycarbonate I would have to use single pieces so building the sections at cost-convenient sizes so-as not to produce a lot of waste would be important.

I have just endured the second day and a noisy night of 30 knot winds, just retrieved both my compost bin lids from the top of the paddock and thanks to the Pembrokeshire banks and stock fencing they didn't end up in St Nicholas.

Good day to burn all the hard rubbish that can't composted.

[robo]

you can get twin wall pollycarb thats only 6mm thick, the modern stuff they use on conservatives is anything from 15 to 28mm and usually has 5 walls, if you glaze each section in one piece it will not matter how thick or how deep the rebates on the frames are,infact you could use spars with no rebates and use a capping to hold the polly carb down they are available at most double glazing supplies, like quey plastics and others

[peter]

Take a look at these http://rhinogreenhouse.co.uk/

[sally wright]

Dear Richard,
as your structure will be attached to a dwelling you are not allowed to use normal glass, it has to be toughened or polycarbonate.

The glass house where I work is beside a tower block and the wind speeds around that have given me some insight into how each glazing material will behave in high wind situations.
Normal glass with glazing pins or nails - the wind rattles it loose, then the panes slide down and the wind then sucks them completely out. They can go for nearly 50 feet before they land.
Polycarbonate sheeting - very noisy in the wind and rain and after about 6-7 years it started to become flexible and the sheets were sucked out from underneath the glazing strips and would be found even further away. It also becomes opaque in the same time and it will grow a fine crop of moss inside the structure. Under more regular high winds I expect it to fail a lot sooner.
Toughened glass is more expensive but it will last for a very long time and be a lot less of a problem. It will also stand up to stray bin lids. That said we did have a company come in to rebuild the glasshouse when we changed from the mixture of polycarbonate and glass to toughened. The major thing with using toughened glass is the fact that it cannot be cut after it has been through the process of toughening so precise measurements are needed. Two Wests and Elliot do a wide range of lean-to's which can be bought to any length to fit the south side of your house. A metal structure will also be more suited to an area of high rainfall than a wooden one. It is also easier to fit out an off the shelf greenhouse with accessories such as shading and ventilation.
Regards Sally Wright.

[robo]

polly carb is noisey in the rain and wind but it will not become flexible with age unless its been cleaned with harsh chemicals it will also start verdigree growing and become unsightly if you clean with water or let the rain wash it you will not have a problem

[FelixLeiter]

Am I missing something ?

May the rules have changed in recent years, i'd like to think I can have a slight mishap without slicing myself in two or getting an eye-full.

The rules have changed as far as building something as a dwelling is concerned, but I guess you're only intending your greenhouse for plants. There's nothing particularly special about horticultural glass, it's just not as good a quality as you would use for domestic glazing, which means it's cheap. Glass never wears out nor discolours. It does not insulate well but light transmission is better (which you'll be glad of in winter — don't get hung up about shading). If you think about it, if you're not going to artificially heat a greenhouse there's no purpose in insulating it. Glass can be a bit dodgy to handle, but I've built several greenhouses and I still have all my fingers.