Greenhouse glass

I've got a flock of horticultural glass (20+) salvaged from two cold frames. 610x610mm.Mostly toughened. West Herts. Tim

Have you looked for Horticultural Glass - which is what it's commonly called?

You should be able to find a supplier near you, such as this one:

Last year I tried and failed to find a supplier of 3mm toughened glass locally. I just used 4mm glass and had it toughened. It looked fine. Jphn

Friends inherited a greenhouse with non-standard common horticultural glass sizes. On the manufacturers web site the official toughened glass were around £40 per sheet. It was subsequently glazed with ordinary horticultural glass sheets that were longer than the originals using DIY Z clips made from builders/fixing band.

Depends on where you are.

Website for info only ie can't order from it.

AK Timms, builders merchants, Brize Norton, OX18 3QB -

A couple of years ago I ordered a 1617 x 610 x 4mm toughened glass panel for a greenhouse. From order to pick up took less than 48 hours (Hampshire). I might get another panel in the new year to replace a "temporary" polycarbonate one.

David doesn't say where *here* is so travel cost might be significant. I wasn't planning to charge him for redundant stuff in need of a clean and taking up space in my workshop:-)>

I'd snap that offer up, thanks, but it's just a bit too far for me. But "horticultural glass" is a new term for me, thanks!

I was unaware of this! Thanks!

I'll be building a greenhouse soon(ish) so I'd be interested to know why you would choose glass rather than polycarbonate ...

It also depends on what glass - plain (horticultural) or toughened. The latter is more expensive and perhaps similar to polycarbonate in price, although it depends on what thickness of polycarb you're aiming for - 4 or 10mm. The latter is expensive but very strong, and will give better insulation so if you're heating the greenhouse it will cost less.

One thing not mentioned in the link above is the annoyance of algal growth inside polycarbonate sheets. It's not easy to completely seal the ends, and if damp gets in you'll soon get algae growing inside the layers. It's unsightly more than anything else.

It gets brittle and cracks. You may find that it cracks when trying to get a tight fit in a greenhouse frame. If too thin it will bend/distort in a gale force wind and part with the greenhouse. Possibly only suitable for small panels. It can be a PITA if cutting down a large sheet yourself.

Unless designed for it a greenhouse frame is unlikely to accept anything greater than 3mm/4mm thick glass or polycarbonate. Multi-wall as suggest in the like is unlikely to fit most(all) greenhouse frames except as one piece for a door.

If collecting it yourself take a decent pair of gardening/working gloves with you.

My (just) 20 year old polycarbonite carport roof shows no sign of cracking. If it did, I would certainly stop walking on it. However if it was corrugated plastic or PVC, that's a different matter.

Yes, 30+ years ago I designed and built a conservatory and put twin-wall polycarbonate on the roof. I think I sealed the top edges but left the bottom ones open so the cavities could "breath".

I'll be designing this myself, and the current plan is to make it out of Oak so there will need to be good clearances to allow for movement. I'm considering using aluminium conservatory bars as rafters, so twin-wall should be fine.

Not in my (very limited) experience, but ease of replacement will be part of the design spec to self.