How to Build a Mediterranean Arch

Measure the width you want for your arch. This should be the horizontal measurement between the doorway or supports that will hold the arch.

Mark this length along an edge of a plywood sheet.

Divide the measured distance by two to get the radius of the arch. Mark the center point of the line you marked along the edge of the plywood in step 1.

Cut a length of string and tie a loop at either end, so that the distance between the two loops is the same as the calculated radius of your arch.

Hold one loop at the center line mark along the edge of your plywood, and place a pencil through the other loop. Draw an arch from one end of your marked line to the other, transferring onto your plywood an even arch. Cut out this arch template along the drawn arch line, then trace it onto another sheet of plywood and cut it out as well. You should now have two half-circle templates that will fit snugly between the supports where you want to erect your arch.

Measure the thickness you would like for the arch. Cut a number of 2-by-4 wood planks to this length, enough to completely cover the circumference of your arch.

Nail through the edge of your arch template into the ends of the cut 2-by-4 sections all along the curved edge of your template. When you are finished, turn it over and nail through the other half-circle template into the other ends of the 2-by-4 sections.

Measure the height you would like the arch to begin. This is usually about head height of the tallest person who will be using the archway. Cut four 2-by-4s to this height.

Support each of the four corners of your half circle template using the four 2-by-4s cut in step 8 in the doorway or between the supports.

Place a keystone brick at the very top of the arch before building up toward it from either side, using bricks with a layer of mortar applied between them. Allow the mortar to dry and cure according to the manufacturers recommendations before removing the template for use on the next archway.