DIY Raised Patio

Measure the dimensions of the site with measuring tape and mark the borders with wood stakes. Tie string around the stakes to create a straight outline for the retaining walls.

Remove the top layer of grass with a flat shovel and pile it on a tarp to plant in bare parts of the yard. Dig out a trench 4 inches wider than the retaining wall blocks and 6 inches deep around the inner border.

Set a level over each side of the site and dig out more dirt as needed to make the trenches level. Tamp the subsoil with a 4-by-4 board until it resists movement under pressure. Fill the trench with 3 inches of 3/4-inch gravel and tamp it until the gravel doesn’t shift.

Empty a bag of ready-mix mortar into a wheelbarrow and stir it with water until it has a thick, batter-like texture. Spread a 1-inch layer of mortar over the gravel with a trowel.

Place the retaining wall blocks or stones on the mortar and press them down with a mallet so they sit even with each other -- check that with the level. Spread 1/4 inch of mortar on each end of the blocks or stones before setting them. Continue until the first course is complete around all four sides. Use a concave jointer tool to smooth the mortar joints and scrape off excess.

Spread another layer of mortar over one side and set the second course of blocks. Stagger the joints so they don’t align with the joints below. Build up the patio walls, laying one course on all four sides at a time until you reach the planned height.

Scoop 3/4-inch gravel into the walled area with a shovel. Tamp the gravel down every 4 inches before adding the next layer. Stop adding gravel once the base is 1 inch below the surface of the retaining wall plus the depth of the pavers or other material.

Cover the base with a 1-inch layer of coarse bedding sand and spread it smooth with a rake.

Position the pavers or bricks in the sand, beginning at one corner and working across in your planned pattern. When all the pavers are laid, pour fine masonry sand on top of the patio and sweep it between the pavers with a stiff-bristled push broom until all crevices are filled.