Below are some guidelines for ratio mixes if you are looking to combine your own concrete for common jobs you may be looking to undertake in your outside space or indoors.
Concrete and mortar mix ratios:
When we refer to “sand” this is sharp sand, and “stone” should be a 10-20mm aggregate. When referring to “part” this is an equal amount of the material using whatever implement you like to measure it, whether a shovel or a bucket, as long as the same item is used each time so the volumes are measured in the same way.
General Purpose Concrete 1:2:3 Mix
A basic, general purpose concrete mix in the UK is made up of a 1:2:3 ratio with 1 part cement, 2 parts sand and 3 parts stone. This is a medium concrete that can be used for repairs or building garden planters
Foundation Concrete 1:2½:3½ Mix
For garden wall foundations or shed bases you will need a 1:2½:3½ mix with 1 part cement, 2½ parts sand, and 3½ parts stone
Paving Concrete 1:1½:2½ Mix
For building steps, pathways, or garage floors where there will be regular footfall a stronger concrete is required with a mix ratio of 1:1½:2½ with 1 part cement, 1½ parts sand, and 2½ parts stone
If you are looking to make a gluing agent for bricklaying or render this is called mortar rather than concrete, although it consists of the same ingredients, minus the stone.
External Wall Mortar Mix
For external brickwork it is a ratio of 1:4 with 1 part cement to 4 parts sand
Sheltered Mortar Mix
For sheltered brickwork it is a ratio of 1:3 with 1 part cement to 3 parts sand
You may want to consider adding a small amount of lime or plasticiser to the mortar to make it easier to work with.
3. How much concrete am I going to need?
You will need to plan this out to work out how much of the different materials you will need to buy. If you are creating a fairly straightforward flat shape such as a shed base, you can use this method to calculate the cubic feet required:
- Multiply the length and the width of the area you want to cover – this will give you the square footage
- Determine how thick you want the concrete to be and convert this from inches to feet
- Multiply the thickness in feet by the square footage to determine the cubic feet
If the shape is a little more complex, you may want to search for and use an online calculator to work out the quantities required.
A ready-mix bag will tell you the cubic feet coverage it can provide, although it is always a good idea to go for a little more than you require just in case.
4. Will I be mixing the concrete by hand, or will I be better using a concrete mixer?
Mixing by hand can be a real chore that requires time and effort and can result in an uneven blend. However, if you only require a small amount of concrete you may choose to make your concrete by hand, especially if using a ready-mix bag.
To achieve a reliable compound, using a concrete mixer will save a lot of time and labour. Take a look at our guide to concrete mixers here, it will help you decide what type of mixer you need for your project and explain how to use it.