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?

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.

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.

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

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

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!

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

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.

Thanks for the reply lads but Im getting different answers: 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.

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.

Found a pdf for you. Hope it helps. http://rugby.cemex.co.uk/downloads/howtomixconcretemortar.pdf Mr. Handyandy - really

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)

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.

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

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.

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.

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.