Author Topic: Glass, toughened glass or polycarbonate  (Read 789 times)

kt.

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Glass, toughened glass or polycarbonate
« on: May 08, 2022, 05:16:52 »
Greenhouse decision:  I ve only ever had glass greenhouses but I am looking to purchase a new greenhouse.  With newer alternatives, I am undecided on Glass,  Polycarbonate or Toughened glass.  I've read the pros and cons but have always had standard glass and wondering if paying the bit extra for toughened glass or poly carbonate is worth it.  Opinions and personal experiences -  good & bad please - especially if you've had both
« Last Edit: May 08, 2022, 05:20:01 by kt. »
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Glass, toughened glass or polycarbonate
« on: May 08, 2022, 05:16:52 »

Paulh

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Re: Glass, toughened glass or polycarbonate
« Reply #1 on: May 08, 2022, 09:13:11 »
If it is for an allotment plot you may have no choice - polycarbonate may be a requirement. Even if glass is OK now, the policy may change and it's not impossible (if unlikely) that it would be retrospective.

If you have children / grandchildren who use your garden, you might prefer toughened glass for their safety and your convenience!

Vinlander

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Re: Glass, toughened glass or polycarbonate
« Reply #2 on: May 08, 2022, 15:50:43 »
If you must have absolute clarity then solid polycarbonate may be more expensive than glass, but if you can tolerate a few % less view then 4 mm twinwall PC is much better insulation in winter & cheaper, lighter, safer (unbreakable) and far easier to cut it to size.

I'd recommend 4 mm twinwall on the north side of any greenhouse (and probably the west side too) - there's less light coming from the north anyway, so in the winter that's where you lose most heat (& where the frost is mostly coming from). I'd also recommend it for any N, W or E roofs, and consider the S ones too (if you really want to see the sky in 4k+you can step outside). A bit more clarity is available from using 10mm twinwall, and 10mm triple wall as almost twice as clear because the ribs are further apart - & fudging the clips for a wider sheet isn't what I'd call Rocket Science.

OTOH The PolyCrub style of all-10mm PC greenhouse is the perfect DIY choice for allotments - it needs no internal bracing or glazing bars, and is better for it (& a hell of a lot cheaper) - they really need that resilience in the Shetlands - that's why it is a charitable community venture there...

Cheers.

With a microholding you always get too much or bugger-all. (I'm fed up calling it an allotment garden - it just encourages the tidy-police).

The simple/complex split is more & more important: Simple fertilisers Poor, complex ones Good. Simple (old) poisons predictable, others (new) the opposite.

Beersmith

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Re: Glass, toughened glass or polycarbonate
« Reply #3 on: May 08, 2022, 18:39:10 »
Polycarbonate is a good material, but the 2 or 3 mm thicknesses are rather bendy and flexible.  I've seen several cases where in windy conditions panels have blown out and resulted in a lot of damage. If polycarbonate is your final choice this is an additional reason to choose 4mm minimum thickness unless you are in a sheltered position.

I once bought some 6mm polycarbonate for another purpose. I used it to make a couple of transparent and insulating crown boards for beehives. Tough and strong and a brilliant material but correspondingly very expensive.
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Tiny Clanger

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Re: Glass, toughened glass or polycarbonate
« Reply #4 on: May 12, 2022, 11:27:14 »
We can have what we like for glazing on our site, but glass is a temptation to the "ball bearing nut jobs" with catapults and rocks.  Most have net shields up where they are within shot reach of the public.  When we took over out plot some years ago, it looked like someone had smashed up a green house on the plot.  We are still unearthing broken glass every time we dig or weed.  We have toughened glass in the greenhouse at home.  Polycarbonate greenhouses get fished out of the local canal on a regular basis whenever we get gales and rough weather.  They are just not heavy enough to stand up the weather.
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Tee Gee

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Re: Glass, toughened glass or polycarbonate
« Reply #5 on: May 12, 2022, 13:29:28 »
I was a traditional "glass" user, but what I noticed on the occasions I replaced panels (after a storm)on other plot holders greenhouses that traditional glazing clips were not suited to most greenhouses.

I found that traditional bendy clips coupled with the bendy polycarbonate were not really compatible!

 I often thought that some form of 'full length' glazing bead would be a better option

Vinlander

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Re: Glass, toughened glass or polycarbonate
« Reply #6 on: May 13, 2022, 14:38:16 »
Polycarbonate greenhouses get fished out of the local canal on a regular basis whenever we get gales and rough weather.  They are just not heavy enough to stand up the weather.

It's a mistake to think that weight alone is going to save any kind of greenhouse (glazing it with lead plates might be effective but seriously counter-productive) - multi-point anchoring is essential and most greenhouses (certainly every single one I've ever entered) are bolted to a concrete base.

Polytunnels traditionally have their cover ends laid flat in a trench and buried under literally a ton of soil, those with covers clamped to a frame (usually contains the side vents) use actual soil anchors of various types. My DIY tunnel uses cast iron pipes driven into the subsoil at 45o and clamped to the uprights with strapping made from flattened copper pipe - none has ever failed - despite the massive sail area and tiny weight.

If you think that polycarbonate is worse, you only have to look at the Polycrub website - any Shetlander will vouch for them - they survive the worst storms of the North Atlantic - orders of magnitude worse than the mainland.

Cheers.

PS. I have used standard clips to hold 4mm twinwall perfectly well - but if you need it to be thinner then I don't recommend thinner twinwall - it's tough plastic - you can squash it a little with pliers - even better if you use blunt-ish pincers to make a thinner line (or valley) where the clips go - the sheet will find it even harder to escape than on slippery glass.

It's easy to use 10mm too - since you can drill through it & fit bolts through to simple clamps on the frame inside (eg. big plywood washers).

PPS. I have no links to anybody making money out of plastic in general, including polycarbonate - I just think that anyone who doesn't make use of its properties is shooting themself in the foot. I can't think of a better use for plastic than making it give many decades of service (when PC finally goes yellow it is still strong enough to hold back soil for a raised bed).

I think that 3 things should be banned - 1st making anything that can't be recycled (eg. cardboard/plastic foil composites), 2nd any form of plastic that isn't UV stabilised (so it turns to dust in a year - I particularly hate the new plastic labels on PET bottles), 3rd single-use plastic in any form - especially if it breaks the first 2 rules.
With a microholding you always get too much or bugger-all. (I'm fed up calling it an allotment garden - it just encourages the tidy-police).

The simple/complex split is more & more important: Simple fertilisers Poor, complex ones Good. Simple (old) poisons predictable, others (new) the opposite.

 

anything