How to Build a Stone Arch Doorway

Shape the Arch

• 1

  Make an arch shape in plywood, following exactly the curve and distance required for your stone arch. This shape, known as the "centering," is made from two pieces of plywood cut to shape with a 2-inch piece of lumber between them.

• 2

  Measure carefully to ensure the door space will be wide enough for the door and supporting timbers after the arch has been built.

• 3

  Choose stones that are exactly the same thickness as the wall.

• 4

  Draw the arch shape across the top of the door space, using the centering as a guide. Your arch will fit into this, so allow for the depth of the arch stones.

• 5

  Cut and chisel out the wall material below your curved line.

Build the Columns

• 6

  Build up columns of square or rectangular stone blocks on either side of the door to the height at which the arch is to begin.

• 7

  Allow for thickness of mortar when calculating height.

• 8

  Check levels carefully with a spirit level or a plumbline.

• 9

  Mortar the stones together and to the wall.

• 10

  Position the centering so that it aligns exactly with the tops of the stone columns. It must be held firmly in place, and scaffolding is the only realistic way to do this.

Position the Arch

• 11

  Use stones shaped slightly like wedges for the arch itself.

• 12

  Test them before mortaring. Place the stones across the centering, working from both sides and using cardboard shims to give the width of mortar.

• 13

  Position the keystone and stand back a few feet to check the structure. Ensure the number of stones is the same on both sides of the keystone. Adjust if necessary.

• 14

  Dismantle the stones, keeping them in exactly the same order.

• 15

  Mortar in one stone at the top of each pillar.

Build the Arch

• 16

  Build inward from both sides.

• 17

  Check frequently by standing back a few feet. Particularly watch that the curve of the stones is even and that the mortaring is equal between stones.

• 18

  Mortar in the keystone.

• 19

  Check the curing time for the mortar mix you used. Do not remove the scaffolding until the mortar is thoroughly cured.