Cheapest way to build a greenhouse foundation

[Beetroot Bob]

Hi people

I've just been given a greenhouse for our new allotment. It's a standard Alu 6' x 8'.

I'm new to all this so my question is what is the best/cheapest way to build a foundation for it? I was thinking of railway sleepers but they work out quite expensive (£24 each for 6'6" long). Could i use conctere blocks ??

[kernowyon]

I did one of my bases using concrete blocks on the corners, half way down the sides and where the door frame is, the rest was using some old concrete path edging, with a couple of split bags of pea gravel from Focus, it came to the grand total of about £10

[Storming Norman]

Hi Bob,

Best and cheapest may turn out to be quite different with a long term structure like a greenhouse. Do you know how you will use it - it will help you decide how to build it. I can tell you what I have learned from how I laid mine if it might help you.

Mine went in 20 years ago. I knew nothing about building then. I laid a flat run [so I thought!] of paving - cheap slabs on a thick sand base with blobs of mortar in the corners. I then put on top an aluminum greenhouse base and concreted it to the slabs [raised either side]. This was all accepted advice.

20 years on it is still there and functioning with many years to go.

What would I have done better:

Checked the height of the site better - it is in a dip. I laid all this too low really, a few more inches of height would be so helpful now.

Made it level - it is not, so gently slops towards the door - maybe the weight of the green house did this? My staging stands on small pieces of slab at one end to fix this problem.
I do not plant in the ground so that is fine but I do get water at one end occasionally when I water as it is all boxed in with the concrete because of the slope.

I should have made the slabs firmer. they were fine for a while but some are now rocky and not much can be done as the greenhouse stands on some of it holding those slabs firm. Slabs outside the greenhouse were a wonderful idea, but have all had to be replaced and raised this year. So the step down to to the green house is accentuated!

I should have thought more about border planting. I chose not to as I was growing toms and they have border soil problems after a while. I use grow bags and grow bag waterers - it all adds to the cost each year. But the green house is clean inside all the time, and possibly warmer in winter.

Please Bob spend time and money on getting this right for your requirements - it will really pay off in the end - it is a building so has to be strong and long lasting. I would recommend a good solid foundation, not wood and not just resting on the soil on blocks as I did. I was lucky really as it seems to be working but if it was more exposed then it would have caused me trouble by now.

Also it you are likely to get wind around the structure put the door in the right place to prevent possible damage. Did you see Toby Buckland's ebay greenhouse on gardeners world? The structure of its fitting was first class and will stand the test of time.- well worth the time and money that must have been put into a £50.00 greenhouse.

[Beetroot Bob]

Thanks for the advice Norm. Time is no longer an issue with gettig a base sorted as sadly the greenhouse I had been offered for free didn't work out. When I went to dismantle and collect it the guy had build his shed on to it and half of it was missing. On top of that without cutting the bolts off there was no way of taking it apart as it was in such a state.

I'll take on board all your points when it comes to sorting out a base when I finally aquire an greenhouse. I had already taken it as a given that it would need to be level. what I hadn't considered is whether or not i was going to have soil in it or not. More research and thinking to be done for mr then !!

[Dobby]

I used some driveway brick we got from freecycle

[Snadger]

Dig a shallow trench and fill with concrete. Make sure its level!

Lay a single layer of bricks, cemented to concrete in required position. If you use old bricks it can work out as cheap as chips!

One of mine is on railway sleepers which I was given for nowt!

[Beetroot Bob]

Thanks for all your replies but it looks like we've landed our selfs a 10' x 12' polytunnel for free !!

Will need new poly but all frame is there including ends and doors.

We be very happy people. The only problem now is whether it's too big for our plot (18' x 60')

[crichmond]

If you still need a base then call the council and ask if they are repaving any streets in the town the old kerb stones are great for using as a greenhouse base.