Greenhouse base on soil

[alldigging]

The spot I have in mind for my newly acquired greenhouse (Thanks Samurailord for helping Nic dismantle it) is on quite good soft soil.

How do I make the base secure there when the ground isn't at all compacted?

Low cost would be good. Low effort even better!

[Greenleaves]

Hi Alldigging

I had a similar issue and the guy next to me was really helpful. First we marked out the footprint of the base and then just walk around for a bit to compact the soil. Using old pallet wood we created a base for the greenhouse base. This will stop the base sinking once the glass is fitted and will eventually rot away by which time the soil will have settled.

[Bill HH]

As above but i would use some small paving slabs as they dont rot. At each corner i would drive in a shapened 3x2 stake (Better still some strong angle iron) and attatch it to the frame. if its a large GH maybe a stake in the middle of the long sides too.If you dont have some sort of solid base (the slabs) you risk it sinking in places and putting a strain on the frame which will start to crack your glass or distort carbonate sheets. presumably you are going to have this for many years so skimping now would be tragic.

[alldigging]

Had a think about what materials we have available.
We have angle iron.
We have possibly some breeze block from an old greenhouse (a bit of effort to get them though)
We have a few slabs but not many and I think I want it so I can plant into soil.

Not entirely sure just walking about will firm the soil enough where I have in mind.

More reading leads me to think that burying the breeze blocks might work, but is a cement/concrete base for them best?

[arpoet]

A few years I was given (free) a greenhouse from an old lady down the road. I rebuilt the frame on soft ground, but resting on stones. Then got some 2 x 2 treated wood, cut to the size of the base and sandwiched between the stones and sunk some post into the soil in each corner, screwed to the base and concreted in with post mix. When set and firm I replaced the glass.
Total cost was about 25 quid for 8 foot X 6 foot Greenhouse.

[Bill HH]

Had a think about what materials we have available.
We have angle iron.
We have possibly some breeze block from an old greenhouse (a bit of effort to get them though)
We have a few slabs but not many and I think I want it so I can plant into soil.

Not entirely sure just walking about will firm the soil enough where I have in mind.

More reading leads me to think that burying the breeze blocks might work, but is a cement/concrete base for them best?

The proper way would be to dig a trench down to firm clay say a foot, and pour concrete into it properly leveled, this need not be over the entire base, just around the footprint, so you can still use the inside soil. Slabs cover a greater area and so would not sink if this is still all around the edge (again properly leveled) you still have your internal soil. Either way you can screw the GH to the base using plugs. If you can get free or cheap slabs so much the better. Blocks would be ok but dig them in, when the soil gets sodden they will sink and stress the structure. Again get it level.

[Potstubsdustbins]

The style/type of glazing will have some bearing on which way you have to go for best results.

Polycarbonate glazing means you main concern is that it is well fastened down so as not to blow away.

Glass glazing your main thought would be to give enough support so as to prevent sinking which would stress the frame as Bill has already pointed out.

[cheapskate chaz]

Have a wander round your neighbourhood to see if there are any skips, should start to have mixed items at this time of year so a bit of skip diving might come up with some materials, don`t forget to knock on the door first and get the hirers permission, you`ll be amazed at to what they chuck out. I work for a waste firm so I come across allsorts for my allotment, a big company chucked out 9" square gate posts that were ideal for my greenhouse base, which incidently, i built from items thrown out into skips...neat eh?

[RaptorUK]

The proper way would be to dig a trench down to firm clay say a foot, and pour concrete into it properly leveled, this need not be over the entire base, just around the footprint, so you can still use the inside soil.

Thats what I did, concrete footings then with a single course of concrete blocks on top to get more headroom and a raised bed effect inside. A little more concrete and I have a concrete "floor" inside the U shaped beds.

[Aberdeenplotter]

(Better still some strong angle iron) and attatch it to the frame. if its a large GH maybe a stake in the middle of the long sides too.If you dont have some sort of solid base (the slabs) you risk it sinking in places and putting a strain on the frame which will start to crack your glass or distort carbonate sheets.

For once I agree with Bill. For my 12ft x 8ft greenhouse, I have angle iron at the corners and the middle of the long sides with recycled lengths of decking which the base is screwed to. It is going nowhere. The angle iron will last much longer than wooden stakes and the decking has been pressure treated so won't be rotting in the near future

[Bill HH]

For once I agree with Bill. For my 12ft x 8ft greenhouse, I have angle iron at the corners and the middle of the long sides with recycled lengths of decking which the base is screwed to. It is going nowhere. The angle iron will last much longer than wooden stakes and the decking has been pressure treated so won't be rotting in the near future

Whats this "For once" i thought we always agreed lol

[Bren In Pots]

Thats what I did, concrete footings then with a single course of concrete blocks on top to get more headroom and a raised bed effect inside. A little more concrete and I have a concrete "floor" inside the U shaped beds.

We did the same thing with my gifted GH only difference was to add tanalised laths between the blocks and the GH.

there's a couple of photos on a blog I started here on the vine :-

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