# Another screed calculation... for 26m2... doh

#### Mr Chibs

Just wondering if you knowledgeable folk could tell me if I have this correct.

26M² of screed needed at 75mm depth, sitting on 100mm kingspan.
Looking at 4:1 mix.

After trawling around trying to find a calculator (can't find the one that used to be a sticky)
I have come up with the following:

Grit sand 1.5m³ = 2400Kg in weight.
Cement .5m³ = 30, 25Kg bags (seems a lot of cement to me)!

Does this sound correct, or have I been a dunce!

TIA

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#### jono_h

Isn’t that 3:1?
4:1 would be 1.6 and 0.4?

#### Mr Chibs

I don't know in honesty, as I find m³ to Kg bloody confusing.

Just used the calculator previously mentioned.

Come in at:
832Kg cement
2486Kg sand

37 bags of cement! It's going up!

#### jono_h

Not sure about that calculator - it makes it a total of 1.95 m2, but then says you’ll need 0.49m2 of cement and 1.95m2 of sand. That’s a 20% contingency.

#### Mr Chibs

Not sure about that calculator - it makes it a total of 1.95 m2, but then says you’ll need 0.49m2 of cement and 1.95m2 of sand. That’s a 20% contingency.

I've looked at this again, and it's talking m³ not m².

If it's to be believed then it's as previously stated, better have three shredded wheat.