Choosing a greenhouse advice

Ah, OK, gotcha

If there is risk from footballs or the greenhouse is on the outside of the hairpin bend for the kid's cycle track!! then the answer is to switch to safety [or is it "toughened"??] glass (or perspex).

Other than that horticultural glass is best (and cheap [relatively!]). Horticultural glass will be the same thickness as the existing panes (although best to measure it, and specify to the glazing people) whereas perspex will be thicker, and give you an issue with lapping adjacent perspex and glass panes.

Perspex bows in the wind (like an aircraft wing, the wind passing over the perspex creates low pressure above, the perspex bows outwards) and is inclined to pop out. People with all-perspex panels in their greenhouse will tell you that the whole lot will pop out and blow into the neighbours garden ... or further ... in a storm. Answer to that is to silicon them in, but its faff and a nightmare if you ever need to move / disassemble the greenhouse. Unless you have a specific safety issue I would sip the perspex route.

Perspex / Polycarbonate etc. will have worse light transmission quality, than glass, over time. No idea if it is significant enough to worry about.

Twin-wall polycarbonate is more thermally efficient. You might put that on the North facing wall for example (and re-deploy the glass panes from there, if they are all the same size, to any missing panes elsewhere). But I would stick to glass.

I have one perspex "pane" in the North end of my glasshouse, by the door, which has a circle cut in it for my vine, planted outside, to "enter" the greenhouse.

I have broken 2 or 3 panes of glass in my greenhouse over the last decade. Twice I have broken a roof pane getting a tall plant in/out and forgotten about the height-reach of the cane/pole in the pot - that's obvious an avoidable accident, with more care; the roof of my greenhouse is very low - and I have also broken a pane in the end "wall" when hit by a stone thrown up by mower or strimmer, I forget which. Damned annoying though!

 

Glass is better for looks and light transmission, probably more durable than the alternatives in terms of not crazing or scratching - as long as you don't break it! But not a good option if you have small children around. However, if the rest of the panes are glass you might as well fill the gaps with glass - and put a little fence round it to keep the rugrats off?

You can buy acrylic panes cut to fit in various thicknesses but expect to pay in the region of £20 per pane. Glass may be cheaper. At least 3mm is recommended to avoid any floppy bits. I've used this firm, local to me so I can pick up, most firms will post out, though.
http://www.sheetplastics.co.uk/index.php?route=common/home

 

I eventually realised that my greenhouse does indeed have an extremely silly little aluminium groove which masquerades as a gutter. What's more, on the fraught rebuild day it was put up so as the slotted hole in the silly gutter is at the far end of the greenhouse tucked between a wall and a fence, so totally useless. Neither of us realised the significance of the tiny hole at the time, too late now!

I can always drill a round hole at the useful end and cobble something together later. Another quality Madahlia installation, no doubt. Yeehah!

 

Mine doesn't have a slotted-hole, that sounds excellent ... mine is just open at both ends - so useless even if installed correctly. Onto it you have to fashion a clip that connects to a skinny "downpipe". The slot-excuse-for-a-gutter blocks with any crud that is floating about, as does the clip and the "downpipe" ... I fashioned a replacement for a clip out of a small piece of lead that came off something or other - church roof maybe! and is shaped like a spout so that it shoots into the water butt. The far end I bunged up with crud so that the water doesn't easily overflow out of that end.

 

Ah well, I'm sure I can find a bit of crud somewhere!

 

Just adding to Kristen's post. I opted for toughened glass for my greenhouse. It is thicker and much safer to have with youngsters around. It doesn't break like ordinary glass that will leave lethal edges, it shatters and resembles crumbs and is much harder to break too. You may have seen a shattered windscreen on a car.....that's toughened glass.

I've had to replace one pane of glass and it was a lot cheaper than I expected. I bought it at a local glaziers and they cut it to size for me too.

 

Dunno about toughened, but 24" x 24" horticultural glass should be less than a £5 a sheet

 

Much cheaper than I thought!

I think I'm going to be really stuck with building this greenhouse. Just can't figure how I'll put the glass in once it's in place?!

 

Is it a new one? Has it got instructions? In my greenhouse the glass was mainly put on from the outside but some of it had to be done from the inside - only possible if you can get your hands through an aperture - or dismantle part of the fence!

 

No instructions and it's a old one, which is no real problem as the previous owner labelled all the bits first. My main problem is that it will have a shed on one side and a wire fence on another.

Here's a picture:

 

Move the base a foot to the left so you can get your hand around a pane of glass (on right side) in order to put the far clip in?

Good job you've spotted that future-issue now! I reckon as you have it the greenhouse and shed are too close together, unless you can glaze the whole right-wall and lift it into place. But I think it would be more tricky than:

Built whole frame
Move frame onto base
Glaze whole thing (starting with the difficult Left Wall)

 

Once the frame is up you could probably glaze most of the back wall if you do it first and stand inside the greenhouse reaching your hand through various apertures to get the clips in. If you could bring the frame forward by even a few inches it would be helpful. You'd have to have a team on hand all working smoothly to position, hold and clip-in the glass as efficiently as possible. You'd have to think through the best order to carry out the work - maybe bottom to top, starting with the R hand side?

The hardest bit would be the corner area between the fence and the shed - could you remove a few crucial panels of wood from the inside of the shed, reach hands through to get the glass clipped and then screw them back in later? Or just cut a mendable hole? It would not really be visible after all, once you have the greenhouse filled and running.

I was only able to fit all the glass on mine by removing and replacing some fence slats as like yours, it is butted up to a wall or fence on two sides. However, the back end of mine is tied into a brick wall and therefore did not need glazing.

 

Do you need glass on the shed side (no light coming in that side)? (roof obviously, but that is presumably easier to do - step ladder inside the curtilage and reach through the unglazed bit to glaze an adjacent roof section).

Fill the openings on the shed side with insulating board - polystyrene or celotex or the like - or even ply etc. if you are not worried about winter insulation.

 

nFrost are you leaving the base as it is? It's worrying me because it won't remain stable as the slabs will move, the greenhouse will move and the glass will 'pop' out or break.