Concrete paving slabs are sections of precast concrete that are used to create patios and walkways. The slabs can be any size and shape. Creating these stones yourself will take a little bit of extra effort but you will be able to customise the size of your stone and create a one-of-a-kind surface for your landscaping. Use these techniques for patios and walkways only. If you plan to use paving slabs for a driveway, purchase them from a company that can guarantee they will not break under the weight of a vehicle.
Determine the size and shape of your paving slabs. Trim a piece of 2 cm (3/4 inch) plywood to match these dimensions using a circular saw. Cut "2-by-4s" to run along the perimeter of the plywood to create the form. Arrange the timber around the exterior of the form and nail in place.
Pour cooking oil onto a rag and coat the inside of the form with the oil. Spread it all over the wood to prevent the concrete from sticking to the mould.
Mix water and pre-mixed concrete according to the package instructions. Stir, adding water until the mixture has a consistency similar to oatmeal.
Pour the concrete into the mould and shake the mould to evenly distribute the concrete. Fill the mould with concrete.
Hold a long PVC pipe across the top of the mould. The pipe should be longer than the mould is wide. Set the pipe so it is flush with the top of the wooden form and screed the top of the mould by pulling the pipe across the top slowly. Let the concrete cure for 48 hours.
Turn the mould over and shake gently to release the concrete from the mould. Move the slab outside and cover it with a tarpaulin. Let the paver cure for seven days.
Dip a paintbrush in concrete sealer. Apply a coat of the sealer to the tops, sides and bottom of the slab. Let the sealer dry.
If you are planning to make a lot of concrete slabs, make more than one mould. You will save yourself time and effort if you can mix, pour and cure multiple slabs at a time.