How to Install a Slate Walkway

Mark the location of your walkway on the ground using landscaping paint. Place a series of wooden stakes along the borders, using a hammer to drive them into the ground. Attach string to the tops of the stakes with tacks to help you visualize the path. Include a 5-inch space surrounding the walkway to allow for the placement of border stones to keep the edge of the walkway even with the surrounding lawn.

Dig the bedding hole for the stones within the confines of the stakes. Use a spade to excavate about 8 inches of soil from the path. Remove the stakes and rope after you finish excavating the hole.

Compact the base of the excavation with a vibratory plate compactor or a tamper. By compressing the soil, you create a surface that can hold the weight of the stones and the bedding materials without shifting over time.

Fill the base of the excavation with 2 inches of gravel. Compact the gravel, then pour in a second 2-inch layer, compacting that as well. The gravel serves as support and drainage for the walkway. Cover the gravel with a 2 -inch layer of sand, also compacted.

Create a mortar for holding the slate in place by mixing the mortar powder with water inside a wheelbarrow. Undercut the mortar with the water, using the spade to mix the 2 materials until you have a mortar that's smooth, possessing the same consistency as peanut butter.

Cover the compressed sand with a 1-inch layer of mortar, using a trowel to spread the mortar evenly.

Place the border stones along the perimeter of the walkway, leaving a 1/8-inch mortared space between them. Set the slate stones into the mortar, with the flattest side of the stone towards the top. Keep the stones level by pushing them as deeply into the mortar as necessary, then using a carpenter's level to make any necessary adjustments. Leave a space of 1/5-inch between the stones. Work from the center of the walkway towards the border stones, arranging the slate so that they come as near the border as possible.

Fill the spaces between adjacent stones and between the slate stones and the border stones with mortar to the level of the top of the stones. Remove any excess mortar with a piece of cloth. Allow the mortar to cure for the length of time suggested by the mortar manufacturer.

Spray a layer of stone sealant over the walkway to protect the stones and mortar from water stains. Allow the sealant to dry for about 48 hours before using the walkway.