Small concrete slab

[Andrew Dwyer]

I want to extend the concrete walkway around my house and would like to know how much materials to buy.
You can see the cleared of weeds area on the photo.

 
It’s a small slab 1.30m x 2.15 m x 9cm deep ( 0.25 cm3 ) with no heavy traffic and will be tiled over afterwards , I have some 10 mm rebar leftover that I will use to “ fashion “ a mesh.
 
Ideally I would like to make life easy for myself by buying sand and cement ready mixed
 

 
and buy bagged gravel and hopefully avoid running short or having a boatload left over.
 
Sooo, my question is:
 
How many bags sand & cement ( 50kg) and how many bags of gravel do I need for .25 cm3 ??

I did look at calculators on google but they all seem overly complicated.

[Cake Monster]

Firstly work out the volume of the area you wish to concrete.

L X W X Depth this will give you a cubic Meter value in your case its 2.51 m Cube  ( not 0.25 cm3  )

Your mix for the Concrete is as follows

3 parts gravel, 2 parts Sand and 1 part Cement dust

I would buy 1 Cube of Gravel and 1 of Sand and 8 bags of Cement from the local hardware store

Cost Approx 800 Gravel, 700 Sand and 820 Cement Total 2320 Baht plus say maybe 50 Delivery

You could also go the ready mix route at a cost of 1900 per cube ( whole cubes only )

[Crossy]

@Cake Monster check your maths ????

 

Handy dandy calculator here https://www.practicaldiy.com/general-building/concrete-calculators/concrete-calculator-met-2.php

 

I make the volume required as 0.25m³  => 1.30m x 2.15m x 0.09m

 

You local builder's merchant will be able to tell you how much sand, cement and rocks you need. Ours sells sand and rocks in bags.

 

[Cake Monster]

Crossy,

You are correct, as is the OP, my humble apologies to both.

Had a funny five there with the calculator ( Memory recall on )

Disregard the amounts in my previous post

Roughly 12 bags gravel, 6 Sand and 4 cement, but ask the builder merchant  to work it out for you

 

[Andrew Dwyer]

Thanks for the replies Crossy and Cake Monster ( ignoring your first reply [emoji51]).
But here lies the problem, according to the calculator:

i need less than 2 bags of cement and Cake Monster says 4 !

I guess I will ask at the merchants .

[Andrew Dwyer]

Firstly work out the volume of the area you wish to concrete.
L X W X Depth this will give you a cubic Meter value in your case its 2.51 m Cube  ( not 0.25 cm3  )
Your mix for the Concrete is as follows
3 parts gravel, 2 parts Sand and 1 part Cement dust
I would buy 1 Cube of Gravel and 1 of Sand and 8 bags of Cement from the local hardware store
Cost Approx 800 Gravel, 700 Sand and 820 Cement Total 2320 Baht plus say maybe 50 Delivery
You could also go the ready mix route at a cost of 1900 per cube ( whole cubes only )

You had me kinda worried there !!

Actually I knew straight away because I had bought a couple of weeks ago 1.5 m3 of ready mix for 3,300 baht.
1800 baht per cube, 900 baht for the 1/2 cube and 600 baht for delivery !

Wonder how many people don’t pay delivery and pick it up themselves [emoji848]

[blinkers]

And what MPA  is allowed for in the calculation?

[Andrew Dwyer]

And what MPA  is allowed for in the calculation?

25 ?

[Kwasaki]

https://theconstructor.org/concrete/concrete-calculator-slab-beam-column-footings/19717/?utm_source=pushengage&utm_medium=pushnotification&utm_campaign=pushengage

[blinkers]

Although it doesn't stipulate MPA, it looks like a 20, my thought was that he may be able to use something like a garden-crete, especially if he is using what the poster refers to as rebar, if its an area that is not going to have vehicles on it, garden crete would work just fine and be cheaper.

[Andrew Dwyer]

Although it doesn't stipulate MPA, it looks like a 20, my thought was that he may be able to use something like a garden-crete, especially if he is using what the poster refers to as rebar, if its an area that is not going to have vehicles on it, garden crete would work just fine and be cheaper.

I think you might be thinking too much about this, the house has a concrete walkway all the way around. At the back of the house it is covered and has a lockable gate at both ends, currently being used for a washing machine, gas stove ( for the real smelly stuff [emoji51]) , storage for tools and 2 bicycles.
We are in and out with the bicycles all the time and would like to make that manoeuvre easier by concreting the corner.

Here’s a better photo to understand what I’m trying to do:



The whole concrete area will be tiled over eventually and the corner will have little traffic, probably a small tree in a planter right in the corner, the manoeuvring of bicycles in and out and probably in the future we will store a scooter ( buying one this year ) when we go away for any length of time hence the rebar to prevent from cracking in the future.

I didn’t really want to go into great detail about my future plans but I have done [emoji51]

I just wanted to avoid buying excessive amount of sand, cement and gravel for a small concreting job !!

[Kwasaki]

1 hour ago, Andrew Dwyer said:

length of time hence the rebar to prevent from cracking in the future.


I just wanted to avoid buying excessive amount of sand, cement and gravel for a small concreting job !!

 

It's less than 3 sq M you could just block pave it.

 

If you concrete and tile after make sure non slip tiles when wet. 

Edited September 30, 2018 by Kwasaki

[Andrew Dwyer]

Soooo, just to tidy this up.

I used the calculator and determined I needed 2 bags of cement.
Went to my local store and basically told the chap I wanted to concrete an area of .25 m3 .
Small amounts of sand and gravel are sold in sacks ( old flour sacks) which weigh approx 25 kg which kinda makes it easier to manoeuvre rather than a pile of sand or gravel outside the gate.
Mixed it in one of those large plastic baths 1/2 bag cement, 2 of sand and 3 of gravel and all went well.