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# How much sand and cement makes a 100L mix

• 06-06-2022 8:51pm
Registered Users Posts: 3,830 ✭✭✭

I am putting down pavers in the back in an area that is 25m sq. I have never worked with mortar before and not familiar with cement mixers. I am planning on getting a mixer from a local hardware supplier which has a mix capacity of 100L. I will be using a 5:1 mix of sharp sand and cement at a dept of 50mm. My question is how much sand and cement can I put in the mixer per load?

i.e. Using a 10L bucket as a measure can I put 10 level buckets of sand and 2 of cement in the mixer per mix or would this be too much? Would 7.5 buckets of sand and 1.5 buckets of cement be better? O =r 5 sand and 1 cement to allow for water?

Also, my pavers are 600mmx600mmx40mm, Would anyone have any idea how many pavers I could lay per load? I have 64 pavers to lay, so trying to gauge how amny mixes I would need.

All advice/guidance would be much appreciated.

• Registered Users Posts: 3,658 ✭✭✭

I would suggest getting help.

• Registered Users Posts: 1,261 ✭✭✭

5:1 is weak, i appreciate a war is on but where did you get the maths on that.

• Registered Users Posts: 984 ✭✭✭

A 100 litre mixer will take 15 shovels of sand and 3 shovels of cement, evenly matched to retain consistency, 10 buckets would be way too much.

There are a lot of variables to accurately predict how many paver that would set

• Registered Users Posts: 22,392 ✭✭✭✭

Well 100 L is 0.1 of metre cubed.

Paver 0.6 x 0.6 x 0.05 deep in theory will take 0.018 metre cubed.

So 5.5 slabs per mix all being perfect.

Placing onto an absorbing surface will take up some volume and uneven ground will account for some more so under 5 slabs per mix.

• Registered Users Posts: 8,239 ✭✭✭

I thought the ratio was 3:2:1 for sand, cement and water?

• Registered Users Posts: 984 ✭✭✭

Not anywhere near it

• Registered Users Posts: 3,830 ✭✭✭

Thanks all for the input, it is much appreciated.

@policarp: I don't know anyone in the building trade and doing it myself to save some money and for the experience. That's why I asked here.

@Gant21: I have read via google everything from 3:1 to 7:1 and I see 5:1 mentioned a few times in YT videos so I was thinking to go with that. Would 4:1 be a better bet?

@Still stihl waters 3: Using a shovel for a novice (me) might lead to inconsistent mixes, which I why I thought to use a bucket and I happen to have a 10L bucket to hand. I can test to see how many shovels it takes to fill my bucket and work from there :)

@mickdw: Cheers for the Math explanation, it is much appreciated. If I go with 4 pavers per mix and I have 64 pavers I will need ~16 mixes :)

@Pussyhands: Never come across that ratio. As above I have always seen the ratio expressed as x:1 where "x" is the amount of sand or sand + ballast and 1 is the cement, then enough water to get the required consistency.

• Registered Users Posts: 30,907 ✭✭✭✭

I don't understand the requirement for cement, other than for haunching the perimeter.

• Registered Users Posts: 2,344 ✭✭✭

Hi,

I've laid a 15m2 patio and have some (non professional) advice / suggestions:

1. Get someone to do the mixing and focus on laying the pavers. Doing both will slow you down considerably and you've got a large area to cover (23m2?)
2. 5:1 mix of cement to sharp is fine for patios
3. Make a slurry to apply to the back of the pavers with a roller before laying. This will ensure they don't come loose. I used PVC, cement and water, ratios available online.
4. Don't worry about the mixing capacity of the mixer, just stick to your ratios and you'll know when you've reached the limit. I used a half bucket as my measure for 1 part. I didn't measure the water but instead looked for the right consistency for me to work with.
5. Add a plasticiser to the mix to make it more workable, available in hardware stores
6. 3 or 4 pavers sounds doable for 1 mix but depends on how level the surface is and how close to 50mm you get it

Best of luck with it

• Registered Users Posts: 984 ✭✭✭

Also use a garden rake to spread the mortor, you'll be surprised how easy it spreads and you'll get the bed fairly good before you lay

Is there a joint to be left on the slab, if there is I'd joint them with a resin filler like joint-tec or similar instead of sand and cement