DIY Advice What is concrete?
Concrete is a mixture of natural aggregates (typically limestone and grit sand), cement and water. Admixtures such as plasticiser, or alternative materials such as Ground Granulated Blast-furnace Slag (GGBS) may also be used depending upon the specific requirements of each project.
What type of concrete do I require?
The strength of concrete required differs according to its application. For example the cement content for a driveway would be much higher than for that of a house floor. Therefore when ordering please state what you intend to use the concrete for.
Foundations for boundary walls, house extensions and conservatories. Garage, shed and summer house bases. House and conservatory floors. Driveways, paths and patio areas. Mixes suitable for pattern imprinting.
When measuring your required area please try to be as accurate as possible. If the measurements are inaccurate, then you will not have sufficient concrete to complete the job. When sizing a large area, particularly for garage bases or driveways, it is vital that you check the depth in several places to ensure that it is constant across the whole area.
Will bad weather affect concrete?
The curing of concrete is greatly affected by the prevailing weather conditions. Heavy rain can wash out the cement powder leading to exposed aggregate on the surface.
If heavy rain is expected, it is advised that the surface be covered with a heavy duty plastic sheet to minimise damage to the surface. The sheet should be suspended above the surface if possible.
When temperatures are slightly above or below freezing point there is a risk of water freezing within the concrete which can lead to cracks appearing on the surface and internally. To avoid this, try to lay concrete when the temperature is warmer.
Alternatively, it is possible to add an Air Entraining Agent (AEA) to the mix. This additive creates air bubbles within the concrete, and so should any water penetrate the surface which freezes and therefore expands, it does so within the air bubbles, minimising the possibility of cracking. This additive is particularly useful when laying a driveway or path which will be exposed to bad weather conditions.
Similarly, in very hot conditions, shrinkage cracks may occur as the surface rapidly dries out. In this situation, the surface should be lightly watered whilst drying or covered with a wet sheet or sacking if possible to minimise the possibility of surface cracks occurring.
How quickly will concrete set?
Typically, concrete has a workable life of about 1.5 � 2 hours. During warm or windy conditions however, the drying time may be more rapid. In this case, concrete should be laid and the surface finished within one hour of arrival at site.
How much concrete will there be?
Concrete is extremely dense and therefore very heavy! One cubic metre weighs approximately 2.3 tonnes and is equivalent to around 20 full wheelbarrows. Therefore, please ensure that you have suitable equipment to move the concrete or recruit extra assistance!
How thick should the concrete be?
For driveways, garage bases and floors, the ideal depth should be a minimum of 100mm or 4 inches. The depth of foundations will vary and is subject to a number of factors including the depth of existing foundations (if any) and local ground conditions. You should consult a builder or planning department representative with specific knowledge of the proposed development in order to ascertain your requirements.
Personal Protective Equipment
PPE should always be worn on construction sites. Hi-visibility clothing and hard hats are a necessity at all times in order to minimise the risk of accidents.
How do I calculate the amount of concrete I require?
Length (metres) x Depth (m) x Width (m ) = m3 required
If you have the measurements in feet and inches only, contact us and we will be happy to convert them for you.
