How to Lay a Patio by Paving Non-Rectangular Slate Stone

Excavate the patio site in the chosen length and width. Remove approximately 6 inches of soil inside the patio site to leave plenty of room for thicker slate slabs. Level the ground inside the excavated area by removing high points and then compact the soil with a mechanical soil tamp.

Place a 3 inch layer of gravel inside the patio site. Compact the layer of gravel with the mechanical tamp to create a firm base for the slate slab patio.

Set the first slab into place in one corner of the patio site. Try to use a slab with a 90-degree corner you can set flush into the corner of the excavated patio site. Turn the slab so that the flattest side point upwards.

Observe how the first slab lies inside the patio site. You want the slab to set almost perfectly level and with between ½ and 1 inch of rock sticking up above the level of the surrounding ground. To achieve this levelness and height, you may need to add more gravel under parts of the slab to build the slab up to level and the desired height.

Use a rubber mallet to tap the slate stone into place on the gravel layer. Continue to set stones into place throughout the excavated patio site, leaving gaps no wider than 1 inch. You may need to piece together smaller rocks to fit around shapes in larger rocks. Fill underneath the slabs as necessary to build the patio surface up to level height. This may take as much as 15 minutes for each stone and is the most time consuming step in the process.

Mix a batch or mortar in a wheelbarrow for easier cleaning, disposal and transport. Mix the ready-mix mortar powder with water, according to directions included on the packaging.

Use a trowel to apply mortar into the small gaps between the slate stones. Wipe away excess mortar with a damp rag and use a joint tool to smooth the mortar down into the cracks.