[ryetek]

My OH and myself have decided to purchase a greenhouse ready for the growing season next year.

I was initially going to construct a base for the greenhouse using compacted hardcore followed by concrete. However it's been suggested that I could use old railway sleepers as the base instead. Now that's got me thinking and asking questions.

I wondered if anyone here has used railway sleepers as a base to their greenhouse? What's the cost of sleepers versus hardcore/concrete? Would the preservatives (e.g. tar and creosote etc) used in sleepers cause any problems to plants? Would the floor be un-even where the sleepers are butted up against each other?

Any help and advice would be appreciated.

Thanks,
Paul.

[Gwiz]

I used the sleepers from the garden centre. They've been OK, haven't rotted. Yet. One day I'm sure I'll regret doing so, but for now all seems fine. I did use a lot of preservative when laying them down, especially on any cuts I had to make.
I don't get any problems with the old creosote as I only use the green house for starting off seeds. Having said that, I have been getting some fine weeds growing in there so The soil can't be all that "poisoned"

[JayG]

Unless you have a secret cheap supply of them I think that leaving aside any thoughts about suitability, fitting problems, and possible creosote and other contamination is the cost - I've had a quick look round and used sleepers seem to be at least £20 each, which would make them pretty expensive for a base and floor (even if you don't want to grow in the border soil you don't have to have a full, solid, concrete base and there are several different ways to support just the structure itself - including sleepers!)

[Gwiz]

I put my hands up to being a skinflint and only using them for something that the base of the green house can sit on, also it is a very small aluminium greenhouse so it didn't cost a lot to do.

[arugula]

Wickes do a 1.8 metre "garden sleeper" for 17 quid - other builders merchants are available.  

In order to price your materials, you would need to know how big the greenhouse and therefore area is to be and, were you going down that route, how deep you would want the hardcore/concrete to be.

For example.. you'll get roughly 10m² coverage to a depth suitable for pedestrian traffic from 1 tonne hardcore which should cost around 9 quid.

If you were using reclaimed sleepers, you could cover them in plastic sheeting if you were concerned about creosote contamination, but this is probably a negligable worry. I wouldn't expect a "garden sleeper" i.e. newly manufactured item to have such treatments.

[ryetek]

Thank you for all the suggestions.

I guess I need to do the maths then. Size of base will be approx. 9ft long x 7ft wide to accomodate 8ft7in x 6ft3in greenhouse.  For the depth of hardcore I was going for 3 inch and then 3 inch of concrete on the top of that.

Unless hardcore/concrete is much more expensive I think this is the way forward for me personally. I also have a friend who I can borrow a whacker plate from to get the hardcore nice and compact.

[richie]

hey ryetec,the advantage of putting it on sleepers is that you can move the greenhouse if your not happy with it and it will give you more height to work but its going to be expensive,personally i would go for the cheaper concrete solution if i was absolutley sure where i was going to site the greenhouse........ive moved mine three times over the years to maximise the weather conditions. good luck.

[carlrmj]

  When I put up my greenhouse I used 2x2 paving slabs which I was lucky to get from                       
   freecycle.

  I had a 8x6 and used 12 slabs,4 1/2 up each side ,and then 1 1/2 between the top and    bottom.
 
The only problem was getting the slabs level as the ground was quite stoney and on a slight incline ,they were anchored to the greenhouse with metal brackets.

[ryetek]

Thank you for the new replies.

richie: I'm not sure that I'll need to move the greenhouse but never-the-less it's worth considering. Thanks.

carlrmj: I did think of using paving slabs but was worried that they might not stay level. We are going to erect the greenhouse at home and not on the allotment. The ground at home is fairly wet and soft. What would be the best way to ensure that the slabs don't move?

Thanks,
Paul.

[carlrmj]

When I made the base for the greenhouse this is the way I did it .

1) Marked out the foot print of the base
2) Removed a layer of grass and stones
3) Levelled off the soil (used a  straight piece of wood),then compacted down
4) Mixed sand and cement as a dry mix to go below slabs( can't remember how much sand    and cement I used)             
5) Placed where slabs are going,levelled off.
6) Put slabs on top of dry mix ,levelled off using spirit level.
7) left for 2 days to settle and set, moisture absorbed up from the ground.
Put greenhouse frame up.
9) Anchored  greenhouse and slabs with metal brackets,masonry drill for slabs and rawl     plugs

Some of the slabs have moved a little ,but I think they will be ok as they are not being walked on .
Hope this is of some use.

Cheers Carl 

[ryetek]

Thanks for the reply Carl. It's given me some food for thought there as it does sound easier than  constructing a concrete base.

Cheers,
Paul.

[JayG]

If I could add another ingredient to your "thinking menu", now is obviously the best time to consider whether you want to add extra overall height to the greenhouse - this could involve using concrete building blocks or bricks instead of (or as well as) paving slabs.

[ryetek]

This is of course true JayG and thanks for the suggestion. However I'm looking at a greenhouse with high eaves (5ft 2inch) so I don't think I'll mount it on raised bricks or blocks as it will be high enough. However that said it may be cheaper to buy a greenhouse with lower eaves and raise it using the method suggested. Ummmm. What to do!

Thanks,
Paul.

[ANHBUC]

If you were using sleepers they can be lethal when wet, very very slippy under foot.   

[ryetek]

If you were using sleepers they can be lethal when wet, very very slippy under foot.   

That's another good point ANHBUC. I don't think I'm going to go for sleepers but I'm still torn between concrete or flag stones.