# how many bags per cubic meter?

Discussion in 'Builders' Talk' started by charlie k, Oct 25, 2005.

1. ### charlie kNew Member

to mix 1 cubic meter of cement at a ratio of 3:1 how many 20kg of sand and 25kg bags of cement will be needed?

2. ### HAMMERBOYNew Member

charlie ...

1 cubic metre = approx 600kg

You therefore need need 450kg sand and 150kg cement

I'd go for 24 of sand and 7 of cement allowing for waste.

3. ### HAMMERBOYNew Member

Sorry, it's early

About 1.5T to a cubic metre

Multiply the quantities in my last post by 2.5

4. ### P F HammerNew Member

I thought nearer 2 Tonne per cubic metre, and more importantly, IT'S 3:1 BY VOLUME, NOT WEIGHT!!!!! At a rough guess, best part of two tonnes sand, thirty bags cement at that mix.
Would guess buying nearly 100 bags of sand could be near £200, as opposed to £50 for bulk!
BTW, sems a tad strong mix, why so strong in such quantity, do tell.

5. ### charlie kNew Member

Hello P F Hammer,
What I really need is 1/2 a cubic meter or cement to screed my extension floor.
I was thinking that 1 bulk bag was equal to about 40 small bags and the cost is £30 plus delivery for a bulk bag and about £45 for small bags that I could collect myself.
Originally I was thinking that 1 cubic meter was about 1 bulk bag and I would only be mixing 1/2 a cubic meter so I would only need about 20 bags of sand but now I have doubts

6. ### Cornish CrofterNew Member

If you're near a B and Q open a trade account, spend over £50 and delivery's free!

A dumpy bag of sand is around £26, and your cement will work out at around 14 bags at £3.20 per pag - just under £45 - you've done it!

Unless you have a pickup with a payload of 1.5 tonnes - you really don't want to be messing around with the time ad hassle of picking up sand or cement in those quantities - 4 or 5 25kg bags perhaps but not 1500 kgs!

CC

7. ### charlie kNew Member

cornish crofter:

how much would you say I need to mix 1/2 a cubic meter at a ratio or 3:1?

or do you think 1 dumpy bag and 14 bags of cement is spot on? seams alot to me!

8. ### Mr. HandyandyScrewfix Select

Approximately,

Sharp sand and cement mortar suitable for floor screeds require (by volume) 1 part
cement to 3½ - 4 parts building sand.
(Per cubic metre 400kg cement/67xbags sharp sand)

Mr. Handyandy - really

9. ### limestone cowboyNew Member

CC is right; a ton of sand and 14 cement. It's much cheaper by the ton so have a full ton instead of bags rather than risk being short.

10. ### charlie kNew Member

I want 1/2 cubic metre at 3:1 so am I right in saying:

200kg of cement (8 bags) and 33 bags sand

OR

1/2 bulk bag (i thought about 20 bags) and 7 cement

Another problem is if I get to much I have nowhere to store it.

11. ### CoolgitNew Member

Correct me if i am wrong but i thought the floor screed ratio was 5:1 ?

12. ### charlie kNew Member

coolgit:

ive been told a few different ratios but the most common and one ive been told and read was 3:1
nobody has suggested weaker than 4:1 though.

the screed is only going to be 40mm so I was told to edge towards stronger mix.

14. ### charlie kNew Member

Mr. Handyandy - really :

Thanks for the PDF, it does help

Another question: does a bag of sand weigh 20kg?
How many small bags in a bulk bag? (i thought about 40)

15. ### P F HammerNew Member

to mix 1 cubic meter of cement at a ratio of 3:1 how
many 20kg of sand and 25kg bags of cement will be
needed?

We have now cut down to 1/2 a cubic metre apparently. The consensus for 1/2 a cube seems to be, 1 tonne sand, 14 bags cement. This should give 3:1 BY VOLUME! ( Use a bucket for easy and accurate measuring. Do not mix it by weight). Therefore, in bags, 50 x 20kg (40 x 25kg) sand, and 14 x 25kg cement. Do watch out for some DIY stores selling cement in 20kg bags, just to foul it all up !
Sorry to be picky, but hope this helps.
BTW, are you really being quoted around £1 a bag for sand, cos from memory, this seems pretty cheap.Thought it was nearer £2.50 each, but could be wrong.

16. ### Mr. HandyandyScrewfix Select

Well, it's something like this.

It doesn't matter what the weight of sand is, because you should be talking VOLUME.

25kg of cement is not the same size(volume) as 25kg of sand.

A tonne of sand is the same weight as a tonne of cement, but there will appear to be twice as much sand if you put them next to each other.

I'm sure you know that.

So it is the size of the bag of sand that is important, not the weight.

So if the bag of sand is the same size as the bag of cement, then it has the same volume(approx).

Do you see where I'm coming from.

So if 400 kg of cement and 67 bags of sand to make a cube at 3 1/2 to 1,
that's 16 bags of cement to 67 bags of sand.

If I haven't confused you yet, I have myself.

Mr. Handyandy - really

17. ### charlie kNew Member

Mr. Handyandy - really:

Thanks for the help, I do understand what you mean but things get a little lost in translation - much easier to talk.

I knew that I wanted to get just the right amount because I had nowhere to put the left over gear.

18. ### P F HammerNew Member

Well, it's something like this.

It doesn't matter what the weight of sand is, because
you should be talking VOLUME.

25kg of cement is not the same size(volume) as 25kg
of sand.

A tonne of sand is the same weight as a tonne of
cement, but there will appear to be twice as much
sand if you put them next to each other.

I'm sure you know that.

So it is the size of the bag of sand that is
important, not the weight.

So if the bag of sand is the same size as the bag of
cement, then it has the same volume(approx).

Do you see where I'm coming from.

So if 400 kg of cement and 67 bags of sand to make a
cube at 3 1/2 to 1,
that's 16 bags of cement to 67 bags of sand.

If I haven't confused you yet, I have myself.

Mr. Handyandy - really

In both my posts, I pointed this out. I suggested using a bucket as a measure to ensure accurate measuring, HOWEVER, we still have to BUY both products by WEIGHTeven if we use them by VOLUME.

19. ### MidAtlantianNew Member

This is quite an old post, but ... actually, the weight or volume issue is a moot point. Portland Cement and sand are about the same weight per volume (both are about 1.6 tonnes per cubic meter) . So if you've got the weight right, you've got the volume right. That means you can rely on the weight on the packaging if you are buying it that way. That might be one reason why some DIY shops package sand the same weight as cement: you can just put in three (or 4) bags of sand to one bag of cement.