[tallulah]

I used the "Old railway sleeper" trick. I've had no problems so far, and I am the "complete nutter" that just whacks it up.

  I believe I fulfill that role in my village too!  But where on earth would I access old railway sleepers, - and I don't think I could carry them on my bike!  (Altho I am the village nutter!)   Actually, I shouldn't claim that title all to myself - there are in fact many excellent candidates for the honour - this be suffolk, after all!

[Scribbler]

We put the rectangular base on fairly well compacted, weed-free soil, and then dug it out where necessary to make sure it was level (well, with a slight drop to collect rainwater in the gutters). Then I dug a hole at each corner for the bolt-on aluminium bits to go down into. When the glass is in, the last thing to do is mix up concrete and put this in the holes.

[Scribbler]

You can't do this in wet weather of course!

[noshed]

Big fat treated fence posts on their side - that's what I used, with metposts at the corners. It was erected by one Irish (me) one Italian and three Turkish nutters and hasn't blown away yet.

[potatopotato]

I used the "Old railway sleeper" trick. I've had no problems so far, and I am the "complete nutter" that just whacks it up.

  I believe I fulfill that role in my village too!  But where on earth would I access old railway sleepers, - and I don't think I could carry them on my bike!  (Altho I am the village nutter!)   Actually, I shouldn't claim that title all to myself - there are in fact many excellent candidates for the honour - this be suffolk, after all!

Hi, I'm a bit late to the thread but started looking at it because I'm hoping to erect my g/h over the next few weeks and have been trying to suss out what to use for the base!

I think I'm prob gonna end up using railway sleepers, which you can buy from eBay - some of the places have pretty large minimum orders but a couple will let you just buy a couple, and will deliver. (it costs a bit more than you'll see on the 'buy it now' price if you do it this way, but I've had someone near me offer to deliver 2x 3m long sleepers to me for £50 - which isn't too bad, esp. considering I got my g/h free)

[Gwiz]

Hi, I've just given a greenhouse to one of our members. That had been just standing on 6 small paving slabs for the past 6 years, in an area of addlestone that is very windy. It was glazed entireley with glass, so the weight was holding it down.

[bridgend]

Our site has been open for less than two years in Edinburgh, so far 3 greenhouses have been completely destroyed. It is a very windy site and  this has shown that it isn't just the base which is important.

If you are building in a nice sheltered spot then you don't need to worry too much, though a level base is still necessary. If you can bolt it down to the base all the better. Sleepers, posts, flags or blocks are all fine as long as they are solid and level. Plenty of greenhouses in sheltered back gardens have lasted for 20 or 30 years on little or no base.

However, if you are in an exposed location it's different. A brand new £800 greenhouse professionally built on solid mortared block foundations with strengthened safety glass: it was still utterly destroyed by the gales last winter. The frame completely buckled and the greenhouse ended up flattened to around 1 foot high, the base was still securely attached to the foundation and much of the glazing still intact. Similar has happened to two other greenhouses. Out of 5 aluminium greenhouses built since the site opened only 2 have survived.

Mine survived, though the glass didn't survive the vandals later in the year.

My tips for surviving wind:

*Good foundations, and securely attached to them.
*Make sure the glazing is VERY well secured. Get extra clips and/or tape - ebay is good for this. Once one pane goes others will and the glazing provides a lot of the structural strength, so the frame might buckle next.
*Re-enforce the frame. Most off the shelf aluminium greenhouses simply aren't designed to survive strong winds.
*Make sure the door is kept securely closed. Greenhouse glazing is designed with strength from outside force in mind. If the wind is blowing into the greenhouse it will blow out glazing easily.
*Build in a location to take advantage of any shelter from the prevailing wind.

I was raised in the far north of Scotland so I'm fairly aware of the damage that wind can do. I may go over the top sometimes, but at least what I build does tend to stay built.

My greenhouse:

8 by 8 foot 20 year old second hand aluminium frame. dismantled and re-assembled on my plot.
Mortared block foundation with treated wood 2 by 4 nailed to wood blocks mortared into top course and sitting on mortar. Base of greenhouse bolted to 2 by 4s.
I have bolted 2 by 4s all round my frame and these also act as supports for staging. Angle brackets can be easily used to secure this to the frame using greenhouse bolts. Additional aluminium bracing at apex and at angle of walls and roof (this was scavenged from destroyed greenhouses with owners permission, buying would have been expensive).
Polycarbonate glazing taped and heavily clipped in place.
Now covered with a wood and chicken wire frame to stop the stones from vandals.

It doesn't look pretty and took a lot of work, but it does the job. I'm still aware that a strong enough wind can destroy anything though.

These examples and tips apply to a very exposed and windy site so in most cases you won't need to worry too much. But I thought I'd share anyway.