[Elaine G]

I have ordered a greenhouse, and am getting someone to build a small wall for it to stand on.
I had intended to put paving slabs inside, laid on sand so the drainage was good, but the builder says this will not work as the slabs will sink and become uneven.
He wants to lay them on mortar and put gravel around the edge for darinage.
Is this a good compromise, or is there a better way?
Any assistance on this would be appreciated.

Thanks

Elaine

[EddieJ]

I can see the builders point, in that he is probably trying to do the best job that he can with no come backs or complaints.

Which ever method is used, you still require a decent sub base, be it concrete, stone or hardcore. There is no reason that slabs laid on screeded sand over a compacted base would ever move, but we all have our own ideas of what is right or wrong.

If it were me doing the work, I always go OTT and would dig out, concrete and lay the slabs on a mortar bed.

[Kleftiwallah]

I would use bricks with holes in and set them on their sides so you get maximum ventilation and airflow through the greenhouse.  It is damp and moisture that brings mildews etc, not lack of heat.   Cheers,   Tony.

[8doubles]

I would use bricks with holes in and set them on their sides so you get maximum ventilation and airflow through the greenhouse.  It is damp and moisture that brings mildews etc, not lack of heat.   Cheers,   Tony.

If you do this you will also get maximum slugs and pests even mice as there will be easy access.

I would put the slabs on sand as you intended as slabs on spots of mortar will also leave voids that can also fill up with unwanted pests.

[hamstergbert]

major advantage of slabs on sand is that if/when you rethink the arrangement you can heave the slabs up and move the sand out or around with a shovel.  Mortar kind of commits you to a permanent layout.

[savbo]

if the slabs do tilt it's easy enough lifting and popping a bit more sand under...I'd go for the flexibility

[JayG]

I think slabs on sand would be fine (it's not as if you will be parking a car on them!)

Quite like the border of gravel idea (mine has a solid concrete floor and shows up every single bit of seepage round the base and frame.) 

[8doubles]

I have slabs on sand and the borders are polythene lined trenches full of sharp sand to take bottomless buckets for the tomatoes.
 Water the trench and feed the buckets, AKA ring culture.

[mumofstig]

I have bare earth inside mine, the path is hard and compacted with use and I can plant in the borders when I want to. No problem............

[Gwiz]

Bare earth in mine as well. I did throw a bit of old plywood on the floor just to keep my shoes a tad cleaner.
Had no problems with it in the last 5 years.

[Elaine G]

Thank you all for your advice.
I have agreed the builder can use morter, but have told him that I want the option of lifting the slabs on one side at a later date.
At the moment I have a home, job and elderly mother to occupy me, so I need it to be clean enough to go in there in the morning in smarter clothes. But counting the years now to retirement

Elaine

[EddieJ]

I'm sure that it will be fine.