From angular retaining walls in an English garden to bucolic, low-slung property walls that line curving country roads, stone provides an ideal building material for homeowners. Building a stone gate post adds both strength and substance to your property, regardless of whether you have a formal or natural landscaping design. Since most stone posts are over 3 feet tall, plan on using mortar to help strengthen and stabilize your post. Stone gate posts are typically ornamental, so don't plan on installing any hinge hardware directly in the mortar unless you'll be hanging an actual gate on the post.
Decide on the dimensions and design of your stone gate post. Will the post be free-standing or part of a wall? If it's part of a wall, you'll need to plan on constructing it at the same time as the stone wall itself in order to ensure that the stones on the walls are jointed together with the stones on your post for maximum stability.
Dig a 2-foot-deep footer trench for your stone gate post. Make sure the trench is at least 3 inches wider on each side than the actual post dimensions in order to provide an adequate base structure for the post. For example, if your gate post is to be 12 inches by 12 inches, then your trench needs to be 18 inches by 18 inches. Fill the footer trench with cement, leveling it off with a 2-inch by 4-inch board approximately 6 inches below the surface of the surrounding ground. Allow the cement to cure for at least two days.
Mark the circumference of your stone gate post with metal rebar posts and string. Pound the rebar posts into the ground just outside the cement edge and run the piece of string tautly between the rebar posts to mark the four faces of your stone post.
Mix a batch of mortar in a wheelbarrow, using a shovel to blend the mortar powder with enough water to create a stiff bonding material that is roughly the consistency of thick cake batter. Scoop mortar and spread it across the concrete base in a 1-inch layer. Press the base layer of stone firmly into the liquid mortar, fitting the stones together closely. Make sure the faces of the stones stay in line with the marking string to ensure a straight, even gate post.
Construct the rest of the stone gate post one layer of stone at a time. Spread 1 inch of wet mortar across the top of the bottom layer of stone and lay the next stone layer, staggering the stone joints between the layers to stabilize the post. Repeat this process for each layer of stone.
Clean smears of mortar from the faces of the stones using a wire brush. Dig the outer edge of wet mortar from between the stones in each layer to create more visual interest and expose the stones for more visual appeal.