How to Install a Flagstone Walk

Draw an accurate to-scale plan of the path you wish to lay, taking into account the measurements of the flags and how wide you wish the path to be. Mark the outline of the pathway with light sand or use wooden pegs.

Check the flags for consistency in thickness, making a note of which may need more or less bedding underneath. This reduces the need to re-bed flags when they do not sit level.

Dig out the earth along the path to a depth which allows the flagstone to sit level with the surrounding grass, or to sit above it, depending on your preference. To calculate the necessary depth, add the thickness of the flag---for example 1 inch---and add a depth of 3 inches for a layer of sharp or masonry sand, giving an overall depth of 4 inches in order to lay flagstones level with the grass.

Remove large stones and rubble to make the bed as smooth and level as possible. Treat weeds and brambles with systemic weedkiller to prevent their regrowing and undermining the path.

Edge both sides of the path with a length of rust-proof aluminum or weatherproofed plastic lawn edging to provide structure and support for a sand bed. This prevents sand from leaching into the surrounding earth and reducing its efficiency at supporting the flagstones. Embed the edging deeply enough that the top edge does not appear above ground level.

Fill in the path with sharp or masonry sand along the entire length. The Flagstone Experts website advises a depth of 3 inches and that you tamp the sand down with a compactor, or use a heavy block of wood to firm up the surface of the sand.

Lay the flagstones along the sand path, using a spirit level to ensure that each flag is level. Deepen or raise the level of the sand to allow for the contours and thickness of each flag.

Knock each flag gently with a rubber mallet to even out any small variations in level. Do not use a metal hammer as this may crack the flag.

Fill gaps between flags with more sharp or masonry sand, by pouring it on to the path and sweeping it in with a stiff broom. Repeat the process when the first sweeping has settled in.

Check the edges of the path to ensure there is no irregularity in the metal or plastic edging and neaten the grass edging alongside.