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16 messages
11/06/2012 at 21:51

I am going to place a 6'x4' greenhouse on a paving stone base. The greenhouse has a metal base but how do I secure the base to the paving slabs so that it does not move?

Thanks in advance for your suggestions!

11/06/2012 at 22:30

Is this on existing paving?  If so, you can drill holes in the slabs using a masonry drill and use rawlbolts to fix galvanised 90 degree angle brackets in the corners, then drill through the base sides and secure to the brackets with stainless steel bolts.  Screwfix are a good place to look for things like that.  If you are also putting down the paving at the same time, you can concrete in the angle brackets when you lay it. 

11/06/2012 at 22:32

A  hammer drill and screws and rawlplugs can do the job, I used 2"x10  screws, but often the greenhouse manufacturers/sellers give fixing instructions on the web.

11/06/2012 at 22:48

The metal base should have holes in to use as a guide to drill holes through the paving stones, plug the holes then screw it down. I also sandwiched a peice of wood around the base in between the metal base and paving stones. If I recall I used screws which were 3-4 inches long.

12/06/2012 at 10:46

I ask why? why put down the paves first? my greenhouse a Robinson was erected straight onto the soil which I did dig out a few inches. They supplied long steel ground anchors which when driven into the ground made the frame solid, it has never moved in nearly thirty years. The single pave path was laid down the centre and I used the two side plots to plant into changing the soil every couple of years.
As time went on I dug out the soil beds and put in a membrane covered with gravel to put pots on now the north side of the greenhouse is staging with warming beds and shelving.
What I am saying is the greenhouse changes as its use also changes, putting it onto a permanent slab base will reduce your options in the future, you are tied to a pave floor or dismantle and rebuild.
Give a lot of thought to what you wish to use it for, independent fastening down will give you many options for the future>

Frank.

12/06/2012 at 13:17

I ask why you need to secure it at all? I have a similar-sized greenhouse on a concrete base and I have never bothered to secure it. It's never moved as far as I'm aware.

12/06/2012 at 14:01

I am with Calendula on this one-has anyone tried to lift a fully glazed greenhouse-it is going nowhere.

12/06/2012 at 15:00

Calendula and Geoff, depends on where you put it.
next door to me due to various badly planned building projects ended up with  a wind tunnel that formed a vortex, greenhouse in the middle.
 Hearing a mighty crash whilst they were away I went round and found the greenhouse had flown six feet or more crashing in a heap on their drive, I left it for them to shift.
just because it should not move it does not say it will not.

Frank.

12/06/2012 at 16:30

Sikaflex, a powerful adhesive/sealant applied with a squeezy gun.

 

13/06/2012 at 00:36
13/06/2012 at 06:30
Calendula wrote (see)

I ask why you need to secure it at all? I have a similar-sized greenhouse on a concrete base and I have never bothered to secure it. It's never moved as far as I'm aware.

sotongeoff wrote (see)

I am with Calendula on this one-has anyone tried to lift a fully glazed greenhouse-it is going nowhere.

I agree.

I have a glass greenhouse on a paving base, which is held down soley by gravity, and which has remained in the same place for many years.

But a crucial point is whether the panes of the greenhouse are made of real (horticultural) glass, or lightweight polycarbonate (which some economy greenhouses are). A glass greenhouse will be far more stable than a polycarbonate one.

Although my greenhouse frame is quite light, the glass is remarkably heavy. The glass in a typical glass greenhouse weighs around 350 kilos. The typical total weight of a polycarbonate greenhouse is around 35 kilos.

An engineer could probably calculate the force that needs to be applied to the side of a pane of glass in order to shift such a weight. Just guessing, I would imagine that force required to move a glass greenhouse would cause the panes to break long before the structure moved.

In my opinion, the biggest threat to the structual stability of a glass greenhouse is slight ground movements over time, which might cause the frame to distort, and thus crack the panes. You need to ensure that the ground beneath is flat and stable.

13/06/2012 at 10:29
Yes it is lightweight polycarbonate - easily moved my two people or if pushed with some force.
13/06/2012 at 10:52
I think I'll get B&Q's greenhouse anchor kit for ??5. Includes drill bit, screws, rawl plugs and metal clips. Thanks for your advice.
Ted
24/12/2012 at 05:23
I echo this question and was interested in answers, it's stupid to say it won't move coz it depends on lots of factors, I agree it's much better to secure anyway, that way you never have to worry, far better to be safe than sorry no matter what the location is.
27/12/2012 at 13:38

We had one with toughened glass (so weighed a lot), well bolted down on to a slab base, but in a horrendous gale a few winters ago, several panes of glass were blown out and eventually the whole frame buckled with the force of the wind, allowing panes of glass to fly out, and you can guess the rest .   Have to admit though, the base never moved from the spot!  As we have a very exposed garden in the north of Scotland, we decided not to bother replacing it - I'd hate to have that clearing up job again!  We now just have a little potting shed where I bring on a few plugs at the window in the Spring .

06/04/2013 at 16:26

My mother had a geodesic dome greenhouse in the 1980s in Edinburgh, and said it was much better in the wind.  I have no idea how easy it would be to buy one now, and doesn't answer the question of fixing it down, but it might be one possibility for people in very exposed locations.  I am currently trying to work out the best base for my new greenhouse, and am veering towards a circumference of paving slabs on a bed of sharp sand.

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