How much sand and cement

gletley

I want to lay a 1" concrete floor in my greenhouse which is 6'x8', can any one tell me how much sand and cement I will need please?

I already have concrete slabs laid down, so the floor will just be put on top of them.

DirectDebacle

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SailorSam

1" doesn't sound very much. Do you think that might break-up easily.
I think you need more than just sand & cement, you need some chippings in there if it's going to be a floor.

smifffy1989

Concrete is normally cement and ballast (sand with stones in), and yes that is very thin. Do the slabs move at all currently?

Using the source4me calculators you will need:

2 x 25kg bags of cement

0.2 ton of ballast (cira 8 x 25kg bags)

27col

Sand and cement makes mortar. Aggregate/ballast and cement makes concrete.

Babbawah

You will not have much success with a sand/ballast & cement concrete at 1" (25mm) thickness. It will be a pig to get a decent surface finish + it WILL break up once it's set & folk start walking on it.

You might get away with a floor screed / self levelling compound but for use in your circumstances I'd hate to recommend which one.

gletley

I've bought cement and ballast, 2 bags of cement and 10 ballast, I will probably do a 2" thick floor, the concrete slabs do not move and they should help with levelling. I suppose the best I can do is give it a go and hope for the best.

Furts

gletley wrote: »

I've bought cement and ballast, 2 bags of cement and 10 ballast, I will probably do a 2" thick floor, the concrete slabs do not move and they should help with levelling. I suppose the best I can do is give it a go and hope for the best.

Bear in mind that the concrete is being laid in a greenhouse. Your mix of 5 ballast to 1 cement is fine (rather strong, but it will be fine). The secret is to not have too wet a mix, then cover the slab with polythene as soon as you can. If you let the slab "dry out" (which it will tend to do in a greenhouse) the surface will be cracked and it will be dusty. The polythene should be down for at least seven days. You can lift it and check for cracks after perhaps a day - there should be none but if there are any close them up and it will be fine. And do not worry if you see moisture on the underside of the polythene - this is what you are needing.

nobulljusttruth

chuck some fibreglass strands in the mix (any builders merchant) it will add some strength.

MX5huggy

gletley wrote: »

I've bought cement and ballast, 2 bags of cement and 10 ballast, I will probably do a 2" thick floor, the concrete slabs do not move and they should help with levelling. I suppose the best I can do is give it a go and hope for the best.

Or you could lift the slabs dig down 6" put in 4" of crusher run or MOT , wacker plate it. Put in some shuttering round the edges and pour 4" inches if concrete. So you never have to think about it again no hope needed.