The secret to making concrete is to use a good powder-packed cement that offers extra strength and adding as little water as possible. Too much water will weaken your structure, so be sure to get the ratios right.
What materials do I need?
- Good cement. PPC SUREBUILD Cement 42,5 N is ideal for making concrete, mortar and plaster.
- Clean concrete sand. The sand should be free of twigs, roots or other foreign matter.
- Clean stone. The stone size should be 13 mm to 19 mm in diameter.
- Clean water. If you can drink it, it is suitable for making concrete. Remember, too much water will weaken the concrete.
How much concrete will I need?
You’ll need to know the measurements of the space you’ll be filling or the structure you’ll be building. Make sure the measurements are accurate. Here are some examples on how to measure surfaces for flat slabs and cylindrical shapes.
1. Flat Slabs
Using a measuring tape, measure the length, width and depth of the area to be filled and multiply these together to work out how many cubic metres (m3) of concrete you need, e.g. length 4,5m, width 4m, depth 0,1m = 1,8m3.
When making concrete to fill a cylindrical shape, use a measuring tape to measure the diameter (width) and depth of the cylinder. Now multiply the diameter by the diameter and multiply this total by the depth and then by 0,8 to work out how many cubic meters (m3) of concrete is needed, e.g. Diameter 0,3m, Diameter 0,3m, Depth 0,5m (0,3 x 0,3 x 0,5 x 0,8 = 0.036m3).
How to mix concrete
When mixing manually, mix smaller batches in a wheelbarrow. If you’re making a large batch, here’s what do:
- Measure out the sand and place in a long, thin heap on a flat, clean, hard surface.
- Pour out the cement on top of the sand.
- Mix the cement, sand and water thoroughly. Add the stones right at the end; this makes it easier to mix the cement. The cement, sand and water mixture, once mixed thoroughly, will look runny but will stiffen as soon as the stones are added. Ensure the stone are mixed in correctly.
PPC has a toll-free helpline to assist you with any queries you have on how to make concrete. Give them a call on 0800 236 368.
Information sourced from PPC.