Greenhouse Foundations

[Ian_5]

Thanks Redthorn, learn something new everyday! like the photo of your greenhouse, nice job.

[Nuke]

Ian_5 wrote :-

i've read differing guides, some saying the steel base is all i need but the majority recommending foundations. the instructions that come with the greenhouse are sparse to say the least and don't state that it needs any further foundations...

Probably they don't want to advise foundations in case it makes it sound like hard work. Unfortunately you need them and it is hard work.

Some posts here are referring a bit loosely to "breeze blocks". As these used to be made from the clinker from gasworks I am not sure true breeze blocks are available any more.

However, concrete building blocks are avaialble in two main types, high density for below the damp course and lightweight for above. For greenhouse foundations you need the high density - the lightweight will soak up water from the ground like a sponge and grow green moss and algae.

I moved a greenhouse last summer to a different part of the garden and found it had been built on two courses of high density 18" long x 9" high x 6" wide blocks, on top of which was a course of special prism-shaped concrete blocks like kerb stones up to 36" long. The "kerb stones" had plastic threaded bushes for the bolts from the greenhouse frame. So the foundations were down to about 2 feet below ground, more than some houses! I think this was defence against rabbits and moles. In the new position I settled for a single course of (new) building blocks under the (salvaged) "kerb stones" - see the picture.

This was a fair sized greenhouse (14x10 feet) and just moving it was heavy work, cost me about £200 with some glass replacement, and took me about two months of spare time. Yet I have read here of someone moving a greenhouse in a day, finishing in time for tea!

[petal]

yes, you certainly do need foundations with a poly carb greenhouse. my husband, ever full of wisdom, told me it doesn't say so in the instructions so it doesn't need it and my poly carb greenhouse got smashed to smithereens 5 years ago. He has never lived that one down, I can tell you.
the glass greenhouse we have just collected (8 by 8) bought for £100 from e bay will be bolted down to patio slabs- that ought to do it? or bricks?

[RedThorn]

sorry I sand corrected, I used the high density thingies told ya I wasn't a builder

Petal, were the slabs cemented together on a cement base underneath? Guess what I'm saying is glass is heavy and you've had one bad experience already, if it were me, I'd go them high density thingies again