Building greenhouse base

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Cactusgirl
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Building greenhouse base

Post by Cactusgirl »

Well I have my greenhouse ordered it's a 16x8. Only problem is that the ground is un level where I want to site it. Don't want to dig down 18 inches one side and 8 the other. So thinking some sort of raised base perhaps for the lower side? I'm hiring road forms and will be getting ready mix concrete delivered for the slab. Does anyone have any experience of siting their greenhouse on a slope? My ground is very solid - too solid to dig out easily by hand. Any advice gratefully received!
FaeLLe
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Re: Building greenhouse base

Post by FaeLLe »

I would build a even flat base no matter what the effort is; invest in it and it will remain okay for a long time.
Slope is not really a good idea considering things shift and move over time.
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rodsmith
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Re: Building greenhouse base

Post by rodsmith »

When I built a greenhouse 6 years ago I put it on a 3" concrete base which I had dug out by hand. The ground sloped a bit. The greenhouse was 8' x 6' and one end of the base was level with the ground and the other about two inches above ground level. In the event, one corner was fractionally off level (less than a centimetre) and I had a bit of a job to get the rood glass in properly. I learned a lesson from this and I would always ensure that a base was completely level before attempting erection.
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Growing a mixed collection of cacti & other succulents; mainly smaller species with a current emphasis on lithops & conophytum.
Darren S
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Re: Building greenhouse base

Post by Darren S »

Our 20ft greenhouse had to go in a spot that dropped 4 feet from one end to the other. We hired a mini digger to level the site. The greenhouse base is two feet below ground level at the end opposite the door (the surrounding soil held back with a block wall) and built up two feet above ground level at the door end ( again - supported with a block wall with concrete steps to the door). The soil within was levelled, compacted down, and then a good 10cm depth of concrete added. The previous property owner's collection of garden gnomes is under there too.....

Base has been there 13 years and we have changed the greenhouse but the base is still rock solid. Definitely do not be tempted to skimp on building a decent base.

So - basically we have a raised base at the lower end as you were suggesting. Digging the whole way down (dropping four feet below the ground surface at the upslope end) would have given us a massive disposal problem, as well as leaving us with the gnomes.
Darren nr Lancaster UK. Growing Conophytum, Lobivia, Sulcorebutia, bulbs etc.
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RAYWOODBRIDGE
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Re: Building greenhouse base

Post by RAYWOODBRIDGE »

Cactusgirl; I agree with all of the above, never take a short cut on the base it will come back to bite you, I know halfway through the first day, you will be asking yourself, why am I doing this, but in the long run it will be worth it, and if your having ready mix concrete then what is an extra 50mm on the the slab to get it perfect and level. Once level the build will be straight forward with everything being in kit form these days the only thing that can let you down and make the build a real pain is the base.

Darren; Be honest you have nightmares :eek:, those gnomes are going to be back :lol:
Ray

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Darren S
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Re: Building greenhouse base

Post by Darren S »

We've since found two more of the b*ggers and a stone otter. My wife insists we don't need another greenhouse just so I can bury them. It was worth a try.

I echo your comment Ray - our new greenhouse is a fantastic Rhino model and even our concrete base was not quite level enough for it so we had to add another skim under the edges. What was OK for a more flexible cedar greenhouse was not flat enough for a new heavy-duty aluminium one with precision-machined bolt holes.
Darren nr Lancaster UK. Growing Conophytum, Lobivia, Sulcorebutia, bulbs etc.
Cactusgirl
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Re: Building greenhouse base

Post by Cactusgirl »

Thanks to everyone for all the advice! Think there is only one way to go and that is digging deep! I like the idea about the block work retaining wall. I think that if I get 4 inches of type 1 well compacted followed by 4 inches ready mix and it is absolutely level then I shall have a greenhouse which will last. I'm buying a Hercules and am looking forward to filling it up!
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RAYWOODBRIDGE
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Re: Building greenhouse base

Post by RAYWOODBRIDGE »

Please post pictures of each stage of the build, always a good talking point on the forum and good advice and comment to any future builders.
Best of luck with the project
Ray

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BrianMc
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Re: Building greenhouse base

Post by BrianMc »

RAYWOODBRIDGE wrote:Please post pictures of each stage of the build, always a good talking point on the forum and good advice and comment to any future builders.
@ Darren ....And mug shots of all those Gnomes who paid a heavy price!
Darren S wrote:We've since found two more of the b*ggers and a stone otter. My wife insists we don't need another greenhouse just so I can bury them. It was worth a try.
First mistake. Now there are witnesses! :shock:

I can just imagine... CSI Lancaster will be round scanning your concrete base :lol:

- - - - - - - - - -
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DaveW
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Re: Building greenhouse base

Post by DaveW »

Plenty of information on the Web for almost anything if you just Google for it, such as "Concrete base for greenhouse", "Greenhouse bases", "Laying concrete slabs" etc, or just substitute "Shed" for greenhouse bases.

https://www.google.co.uk/?gws_rd=ssl#q= ... 8639348454

https://www.google.co.uk/?gws_rd=ssl#q= ... 8639622891
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