To install concrete blocks effectively, begin by excavating the area to a depth of at least 200mm–250mm (depending on whether it is for a patio or driveway), adding 17mm of slope/fall for every metre of paving width/length. Two taut string lines should be used to guide alignment along the length and breadth.
Next, install a breathable weed membrane and fill the base with crushed stone (MOT Type 1). This should be compacted in layers with a plate compactor to a finished thickness of 100mm–150mm.
Install your perimeter blocks or kerbs on a 100mm bed of concrete and haunch the outside with concrete to lock them in place before proceeding.
Now, lay a 30mm–50mm bed of sharp sand. This sand should be slightly damp and levelled using “screed rails” and a straight-edge timber. Level the sand so it sits approximately 10mm–15mm above your desired final height; the blocks will be vibrated down to the string line later.
Begin laying your concrete blocks starting from a straight edge or a corner, working upward in your chosen pattern (e.g., herringbone or stretcher bond). Place the blocks tightly against one another, leaving a natural 2mm joint. Stand on the laid blocks as you work—never step on the prepared sand bed.
Once all blocks are laid (including any cuts made with a block splitter or diamond saw), sweep the area clean. Spread kiln-dried sand over the surface and brush it into the joints.
Now, use a plate compactor with a rubber paving mat attached to run over the entire area. This vibrates the sand into the joints and pushes the blocks down into the grit sand bed to create a locked, “intermeshed” surface.
Top up any joints where the sand has settled during compaction. Ensure the joints are completely full to the surface to prevent movement. Lastly, consider applying a breathable sealer to protect the concrete from oil stains and to help stabilise the jointing sand.
See our guide to block paving for more information.Â
