[Scribbler]

Any thoughts about foundations for the new greenhouse? We're looking to stick it on compacted soil and then cement in the corner spikes when it has all been put together. You may say paving slabs or bricks, but with soil you have some scope to adjust levels so the whole thing is square, and the glass goes in without too much wailing and gnashing of teeth.

Observations welcome. No rush - it's being delivered in about 4 weeks!!

[helluvatractor]

i put up a 12 foot one a month or so ago.  i scrounged as many breeze blocks as i could, had to buy a few.  dug a small trench around the perimiter the width of the blocks, laid the first layer of blocks, flat down inside the trench, (so the top was at ground level, then laid a second layer on top of these, (overlapping - brick-style for strength) then rawle plugged and screwed the bottom of the greenhouse to it.  took about a day, but it's still standing !!

[si-mate]

We built frame using tanalised 4x2 then cut some stakes using 2x1 and bashed 2 of these in per side and screwed the frame to them, then screwed the greenhouse to the frame.

[John]

I've built a base with breezeblocks for a greenhouse in a garden, involved digging a trench, rubble in the base then concrete to form a foundation. Lot of work but very stable and long lasting.
On the allotment I used 8"x4" sleepers attached to 2' fence posts sunk into the ground at the corners. Treated wood should last for many years and it was a lot easier and faster to do. Also easier to correct levels and square.
On firm ground I would consider using ordinary treated fence posts laid flat. I think these would be OK but since I had the 8x4s already it made sense to use them.
As many allotment sites frown on permanent structures, wooden bases have the benefit of being easy to remove if required.
Slabs just laid on soil do tend to be uneven and can move especially in dry weather / wet weather when the ground shrinks / expands.

[Bobby T]

Most home use alloy greenhouses are only around four foot six under the eaves where you tend to grow most of your plants.Remember toms will reach upwards of five foot and so problems with staking, tying in ect.Similar to John I built my 6X10 on three courses of brick on a levelled concrete foundation.More room for your plants and you dont have to move around in there like Quosimodo! The only problem you will need a step or ramp in the doorway.    Bob.

[new_2_veg]

when we done ours we lifted it up 15"  on hard wood bearers to give more growing height, we put in a slab path in the middle leaving soil round the outside for dranage, if you are going to rack it out ive seen people slab out the whole floor but leaving 100mm or so with gravel in around each slab, that sorts out the dranage so it can be kept clean and mud free

nathan

[shaun]

like this
and like nathan says it gives you an extra 10" in the height

http://www.chat.allotment-garden.org/album_pic.php?pic_id=311