Good evening,

the structure for our greenhouse has arrived. While the previous owner
claims that the arcs just need to be set on flat ground, I have a doubt,
that the greenhouse can withstand the winds in this way.

The arcs end in steel-boards with a “Z-profile�, like in this drawing (I
hope you use a mono-spaced font for the news):

| top
right _________ left |
/________/ | | |
| | | | |
| ( ) | | | |
|________| | \__|_|__
/________/ | \
| bottom

Does someone know this kind of greenhouse structure?

The profile has certainly a meaning and my wife and me consider sinking
the boards low enough into the ground to put weight on them; either
stones or cement.

The whole greenhouse will be 6x20m (120m²) with vertical “walls� up to
about 1.9m, which means a considerable weight, but also a considerable
surface. Even if I choose an intelligent orientation and a good
compromise between insolation and wind resistance, some additional
anchoring should be needed, I guess.

TIA,

Michael

--
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On 03/12/2014 22:30, Michael Uplawski wrote:
Good evening,

The whole greenhouse will be 6x20m (120m²) with vertical “walls� up to
about 1.9m, which means a considerable weight, but also a considerable
surface. Even if I choose an intelligent orientation and a good
compromise between insolation and wind resistance, some additional
anchoring should be needed, I guess.

Absolutely essential I would say. Your structure will be a fair bit
heavier than a normal domestic garden greenhouse, but you really don't
want it being moved by the wind during a powerful storm.

I would also recommend replacing the cross bracing on the prevailing
wind side with a heavier gauge of aluminium angle. My 3x6m failed in the
winter storm of 1997 when the wind loading at ~100mph bent one of the
standard corner reinforcing struts which shattered a pane of glass.

Once wind got into the structure it lifted the roof and doors off. I
guess it depends how exposed you are and the intensity of the storm. It
is well worth keeping some twinwall or at a pinch plywood for quick
running winter repairs if you will be heating it for tender plants too.

http://www.nezumi.demon.co.uk/garden/gizmos/gizmos.htm

Nearby commercial glasshouses and polytunnels were also trashed.

--
Regards,
Martin Brown

On 03/12/2014 22:30, Michael Uplawski wrote:
Good evening,

the structure for our greenhouse has arrived. While the previous owner
claims that the arcs just need to be set on flat ground, I have a doubt,
that the greenhouse can withstand the winds in this way.

The arcs end in steel-boards with a “Z-profile�, like in this drawing (I
hope you use a mono-spaced font for the news):

| top
right _________ left |
/________/ | | |
| | | | |
| ( ) | | | |
|________| | \__|_|__
/________/ | \
| bottom

Does someone know this kind of greenhouse structure?

The profile has certainly a meaning and my wife and me consider sinking
the boards low enough into the ground to put weight on them; either
stones or cement.

The whole greenhouse will be 6x20m (120m²) with vertical “walls� up to
about 1.9m, which means a considerable weight, but also a considerable
surface. Even if I choose an intelligent orientation and a good
compromise between insolation and wind resistance, some additional
anchoring should be needed, I guess.

TIA,

Michael

Sorry but I cant understand your drawings.
I would lay a base of concrete blocks set on a couple of inches of
concrete, this will enable you to get a better level for the base.
Set an inverted 2 to 3 inch wooden wedge between every 2nd block.
When set I would paint the top of the blocks with bitumen then lay a
damp proof membrane on top then nail a 4inch x 1 inch plank along the
top, nailing it to the wedges.
Give the timber an extra coat of wood preserver (or more of the bitumen).
You can then fasten the base plate to the timber, I drilled every 3 ft
and screwed it down.
http://i240.photobucket.com/albums/f...psa095aca1.jpg
Remember to have a slight fall along the length of the greenhouse, say 1
inch in 10 ft.
I don't know what braces you have inside but I would have a brace every
glazing bar both at the eves and the ridge, easy to make from angle
aluminum, doesn't have to be heavy weight, but do use angle not flat bar.
took me about 2 minutes each to make, just need a hacksaw and a drill,
and a pair of pliers will do to bend the ends.
http://i240.photobucket.com/albums/f...ps16384fe4.jpg
If you can find out the make then you may be able to get the
construction details.
Pity you didn't have pictures of it when it was up, showing details of
the joints etc. helps a lot if you have never constructed one before.

On 03/12/2014 22:30, Michael Uplawski wrote:
Good evening,

the structure for our greenhouse has arrived. While the previous owner
claims that the arcs just need to be set on flat ground, I have a doubt,
that the greenhouse can withstand the winds in this way.

What I have done is bolt the base of the Greenhouse to the concrete
base (mostly paving slabs).

The "tabs" (made from the strip of angle supplied to anchor to grass)
http://www.cheesesoup.myby.co.uk/images/GH6.jpg
can be discerned from this image
http://www.cheesesoup.myby.co.uk/images/GH5.jpg

A couple of the glass panels have silicone sealant 'gluing' them in
as well as the clips, so far (fx:touches wood) no wind damage despite
living on a hill in Scotland.

Full(ish) construction of greenhouse at:-
http://www.cheesesoup.myby.co.uk/gh1.html