Do I really need that much concrete ???

[robsbots]

Hi all. I'm new to the forum. I just have a quick query before buying some concrete.

I am putting up a green house and have dug some footings for a concrete base. The base will just be a ring of concrete, not the whole floor. The foundation trench is a total of 12.6m around all four sides of the green house by 0.30 m wide by 0.25 m deep except the front which will be 0.60m wide by 0.25m deep

The greenhouse is 8' x 6'.( 2.44m x 1.8m)

i envisage putting 0.15 m thick layer of hardcore in the bottom of the trench then filling the rest up with concrete. 0.10 m thick

I calculated the concrete required to be 38 cubic meters and weighing in at about 2.3 tons . This seems like a lot of concrete.
I'm just after a sanity check really to make sure this is around the right figure.

If this figure is about right, is it feasible to mix this by hand in a wheelbarrow and lay it in one day ?

Thanks

Rob

 

[Static]

Urm i make it somewhere between 1.5 and 2cu ish.. so your a little off..

Try
2.44x0.25x0.6 = urm around the 0.4cu mark
10.2x0.25x0.3 = 0.8 ish
2.44x1.8x0.1 = 0.4 or there abouts..

Anyways.. im going to keep looking for my calculator now..

 

[freddiemercurystwin]

Where do you get those figures from Static?

Try
2.44x0.3x0.1 = 0.08 X2 = 0.16 (sides)
+
1.8x0.3x0.1 = 0.054 (back)
+
1.8x0.6x0.1 = 0.11 (front)

So total required = 0.25m3

The size of your foundation is not very clear tbh

 

[robsbots]

I think it could actually be less because the wide part of the trench is on one of the shorter sides so it could be :-

Trench depth = 0.25 of which 0.15 is hardcore leaving 0.1 concrete and so .....

length x width x depth of concrete = Cubic m of concrete
2.44 x 0.30 x 0.10 = 0.07 ish
2.44 x 0.30 x 0.10 = 0.07 ish
1.80 x 0.30 x 0.10 = 0.055 ish
1.80 x 0.60 x 0.10 = 0.10 ish

Totaling 0.30 ish m Cubed

That sounds a bit more reasonable. Previously I used an online calculator and must have gone a bit astray somewhere....

Does this sound a bit more sensible ?

 

[robsbots]

Sorry Freddy. Was posting my reply as you posted yours. They seem to tally quite well though.

Thanks guys. Could have been difficult trying to sell a LOT of second hand concrete. Quite a tough market to crack

 

[freddiemercurystwin]

edit

 

[noseall]

13m x 300mm wide x 300mm deep would require 1.17m³ of concrete which would equate to about 2 tonne of ballast and 14 x 25kg's of dust.

So, why don't you but a tonne sack of ballast and 7 bags of dust then see how much more you need.

A join in a greenhouse footing aint gonna hurt none.

 

[TonyW2]

0.28 cubic metre

 

[noseall]

...Just to add to my original post:

Don't bother with hard core in the trench bottom just use concrete hence the thicker or deeper concrete.

 

[Static]

Sorry miss read the bit about putting in hardcore under the footing and read it as a slab over lot..
Do as noseall says all concrete