How to Build a Sandstone Arch

Select the location you wish to install your sandstone arch, clear the area and ensure it is level.

Construct a plywood frame you will use to build the arch around. This should be made by cutting a plywood sheet to the depth you wish the arch to be, by the height at the top of the arch. Two of these templates should be created, then supported from the inside using 2-by-4 lumber cut and nailed from the outside of the plywood arch into their ends. The sandstone arch will be built around this plywood frame, so it must be suitably strong. Ensure there is a 2-by-4 support spaced every 12 inches around the perimeter of the plywood frame.

Place the plywood frame where you wish the arch to be erected.

Place a key brick at the very top of the arch to act as a reference point to ensure both sides of the arch are built up evenly.

Begin laying down sandstone bricks, with a layer of mortar, premixed with a small amount of crushed sandstone sand for color, about 1/2-inch thick applied to each contact surface.

Lay the bricks against the plywood frame with their ends making contact with the frame itself, radiating around the curved arch. Select appropriate thicknesses of bricks in order to reach the key brick with the same number of bricks on either side of it.

Allow for the mortar to cure according to the manufacturers instructions, then remove the plywood frame and enjoy your new feature.