I am hoping to construct my first ever greenhouse this winter, as a DIY
project, doing my own design & sourcing materials rather than buying a kit.
What I'm wondering is:
1. If I use polycarbonate for the roof (as I'd like to for strength and
lightness), will it let through enough of the light spectrum to be good for
the plants, or do I need to use glass?
2. Is standard annealed glass OK to use in the windows, or do I have to use
some special 'horticultural glass'? If so, how does horticultural glass
differ from normal glass?
3. Is there any regulation relating to domestic greenhouses which say I have
to use safety glass?

( almost) all comments gratefully received!

"Duncan Heenan" wrote in message
...
I am hoping to construct my first ever greenhouse this winter, as a DIY
project, doing my own design & sourcing materials rather than buying a
kit.
What I'm wondering is:
1. If I use polycarbonate for the roof (as I'd like to for strength and
lightness), will it let through enough of the light spectrum to be good
for
the plants, or do I need to use glass?
Polycarb lets more in than glass does.

2. Is standard annealed glass OK to use in the windows, or do I have to
use
some special 'horticultural glass'? If so, how does horticultural glass
differ from normal glass?
It is thinner
3. Is there any regulation relating to domestic greenhouses which say I
have
to use safety glass?
Dunno abou that one.
I have some plans here for a great greenhouse made from the small
corrugated plastic sheeting. Basically you get some horticultural hosepipe,
the stiff stuff. Cut it to lenght and shove the ends in the ground to form
an arch high enough for you to walk under. Make 3 of these so that the total
distance from the 2 outer ones is 8 feet, then get some of the corrugated
plastic sheeting and starting and ground level attatch it to the polypipe by
drilling small holes and using plastic cable ties or whatever. Carry on
until you have gone up and over. It will allow plenty of light in and you
don't have the danger of glass breaking. You can also make it whatever size
you like fairly cheaply. You need to make some ends and one could be solid
plywood or sterling board cut to shape and the other some clear plastic. The
plans are out of a back issue of country smallholder and I will look to see
which issue it was if you wanted to get yourself a copy of the back issue.
I plan to make myself this particular greenhouse as it is simple and quick
and with 7 brainless dogs in the yard, I can well do without vet bills for
stitching them up after they run through the glass :0(

In message , Duncan Heenan
writes
I am hoping to construct my first ever greenhouse this winter, as a DIY
project, doing my own design & sourcing materials rather than buying a kit.
What I'm wondering is:
1. If I use polycarbonate for the roof (as I'd like to for strength and
lightness), will it let through enough of the light spectrum to be good for
the plants, or do I need to use glass?

It should be ok - Lots of the year GH end up being shaded anyway.

What about something like a Keder house?

http://www.kedergreenhouse.co.uk/

2. Is standard annealed glass OK to use in the windows, or do I have to use
some special 'horticultural glass'? If so, how does horticultural glass
differ from normal glass?

It doesn't 'Hoticultural/greenhouse glass' is just cheaper, normal
glass.

3. Is there any regulation relating to domestic greenhouses which say I have
to use safety glass?

No, leastways not that I'm aware of , never heard of it and standard
retail GH come with normal glass
--
Chris French and Helen Johnson, Leeds
urg Suppliers and References FAQ:
http://www.familyfrench.co.uk/garden/urgfaq/index.html

Duncan Heenan wrote:
:: I am hoping to construct my first ever greenhouse this winter, as
:: a DIY project, doing my own design & sourcing materials rather
:: than buying a kit. What I'm wondering is:
:: 1. If I use polycarbonate for the roof (as I'd like to for
:: strength and lightness), will it let through enough of the light
:: spectrum to be good for the plants, or do I need to use glass?

I have a greenhouse built entirely from poly-c, it's a solid construction
which has lasted longer than the glasshouse, whose roof struts are now
rotting away, plants grown in both grow at the same rate and tomatoes
ripened at the same time (neither has been used for a few years, but next
year they will both be in full production again)

:: 2. Is standard annealed glass OK to use in the windows, or do I
:: have to use some special 'horticultural glass'? If so, how does
:: horticultural glass differ from normal glass?

It's thinner and cheaper, if you can afford poly-c for the entire thing - it
would last a lot longer, less of the timber is open to the weather, you get
less condensation running down it and it's warmer in winter than glass.

:: 3. Is there any regulation relating to domestic greenhouses which
:: say I have to use safety glass?
::
Not that I'm aware of, poly-c has the other obvious advantage...about ten
years ago, my dad fell through his greenhouse at his allotment, he suffered
what appeared to be a one inch cut in his side, just under his left arm, but
upon further investigation it turned out to be a 10 inch shard which snapped
off inside him, missing his heart by less than 5mm - he was in the
cardio-thorassic unit of Liverpools Broadgreen hospital for two weeks after
surgery to remove it, they gave it to him wrapped in cotton wool and it
still had the whitewash on he'd used for shading!

"Duncan Heenan" wrote in message
...
I am hoping to construct my first ever greenhouse this winter, as a
DIY
project, doing my own design & sourcing materials rather than buying
a kit.
What I'm wondering is:
1. If I use polycarbonate for the roof (as I'd like to for strength
and
lightness), will it let through enough of the light spectrum to be
good for
the plants, or do I need to use glass?

A polycarbonate roof is fine. If you use the double walled material,
make sure that the ends of the tubes are closed off so as to be
waterproof, otherwise you will get algae growing on their inside
surfaces.

2. Is standard annealed glass OK to use in the windows, or do I have
to use
some special 'horticultural glass'? If so, how does horticultural
glass
differ from normal glass?

Unless my memory is letting me down, "horticultural glass" should be
slightly cheaper than domestic window glass, being slightly less
perfect. By all means use it.

3. Is there any regulation relating to domestic greenhouses which
say I have
to use safety glass?

Huh??

( almost) all comments gratefully received!

Was the "huh" received gratefully?

Franz

On Mon, 8 Nov 2004 14:36:30 -0000, "Duncan Heenan"
wrote:

3. Is there any regulation relating to domestic greenhouses which say I have
to use safety glass?

IF (as I did) you build a lean-to off the house and can get in to it
via (say) a french window from the house then YES it must be safety
glass. safety glass is more expensive but more visually attractive as
it comes in made-to-fit big sheets (some 11' by 2' in mine, and bl**dy
heavy)

hth Derek

In article ,
says...
On Mon, 8 Nov 2004 14:36:30 -0000, "Duncan Heenan"
wrote:

3. Is there any regulation relating to domestic greenhouses which say I have
to use safety glass?

IF (as I did) you build a lean-to off the house and can get in to it
via (say) a french window from the house then YES it must be safety
glass. safety glass is more expensive but more visually attractive as
it comes in made-to-fit big sheets (some 11' by 2' in mine, and bl**dy
heavy)

Not, what I read on the inforamtion thingy I got recently from our glass
place when we had to replace a panel in a french door.

If it goes to ground level or, judging by the map and examples, up to
about 8 year old child height, then it can't be pane glass and must be a
minimum of toughened glass.

We were buying glass for a lean-to conservatory and had the two options
of buying laminate glass or toughened for the window that needed
replacing. Laminate could be cut to size on the premises, but toughened
needed ordering. Lamintate was more expensive.

Horticultural glass is just pane glass, but a bit thinner with no
special treatment to make it safe. The properties of the three types
are...

Single layered pane glass. Easy and cheap to manufacture, when broken
will break into shards. These shards will be sharp, pointed and
difficult to clean up without injury.

Toughened. The glass is more difficult to break, but when it does it
turns into mostly small cubes of glass (such as you see after a car
accident or break in). These cubes are much less likely to injure and
you'll be clearing them up forever. (I imagine that cutting the stuff to
size is an interesting process)

Laminate. Two sheets of thin glass with a layer of clear polycarbonate
bonding them together. When broken, no shards or cubes will be created
as the pane remains intact (although damned difficult to see through).
This is the stuff that windscreens are made from. It is possible to
increase the strength of this glass by inserting a wire grid in the soft
layer (as seen mostly in institutional buildings such as hospitals).

Once the glazing is no longer attached to a building, all bets are off.
I have laminate in a couple of panes that I've replaced in the
conservatory, but it is acceptable for me to replace the pane glass in
my greenhouse just 50' away with the same stuff, indeed I've failed to
find a source that will sell me something safer to replace the lower
panes. I've resorted to sticking a plastic coating to the outside of any
pane that our toddler could plausibly break.

Warwick

Warwick wrote:
[...]
Toughened. The glass is more difficult to break, but when it does
it
turns into mostly small cubes of glass (such as you see after a car
accident or break in). These cubes are much less likely to injure
and
you'll be clearing them up forever. (I imagine that cutting the
stuff
to size is an interesting process)
[...]

I found out that one of the reasons it's expensive is that it has to
be cut to size before being tempered by going back into a kiln. But
the actual cutting, the man told me, isn't any different from cutting
ordinary glass.

panes. I've resorted to sticking a plastic coating to the outside
of
any pane that our toddler could plausibly break.

I did that, too, way back: it was reassuring at the time, but I often
wonder how much difference it would have made.

Mike.