Building a brick arch

Once you’ve mastered the basics of brickwork, you may want to try something a bit more advanced such as building a brick arch which frames outdoor space and adds an interesting feature to any property. Here’s a basic guide on the steps involved.

Level of difficulty

Level 3: Advanced

What you need

  • Gloves
  • Goggles
  • Tape measure
  • Saw
  • Plywood
  • Bricks
  • Hammer
  • Nails
  • Mortar
  • Bricklaying trowel
  • Straight edge

The steps to follow

  1. Start by building a wooden former to lay the brick arch.
  2. Take the distance of your pier separation and divide it by two to get the radius of the curve. The pier separation is the distance between the left and right hand side of the proposed brick arch.
  3. Based on this radius, draw out two semi-circles on plywood and cut them out with a saw.
  4. Next, cut a piece of board with the same width as the arch and same thickness as the wall.
  5. Nail the semi-circles to the long edges of the board.
  6. Cut scrap timber spacers to the same width as the base of the board, and nail them to the curved edge of the board.
  7. Make two T-shaped wooden props to the exact same height as the side piers. Make sure that the wooden props are level with the tops of the piers.
  8. Nail them against the inner faces of the side piers.
  9. Lay the first brick on each side of the arch on a wedge-shaped mortar bed.
  10. Press the stretcher face (the underside of the arch) firmly against the former.
  11. Draw a vertical line on the face of the former, right in the middle of the semi-circle.
  12. Dry-lay a brick on top of the former to make the keystone.
  13. Continue dry-laying the bricks on the former to calculate the amount of bricks you’ll need to create the arch. Remember to include the thickness of the mortar joints, which should be 3 mm (1/8 in) thick.
  14. This time apply the mortar joints while you relay the bricks on the former until you’ve reached the keystone. Apply more mortar on each face of the last brick and tap it in.
  15. Check with a straight-edge that the face of the brickwork is flat and straight on each side of the opening.
  16. Spread a layer of mortar of about 2.5cm (1in) on the upper surface of the arch.
  17. Finish the course by laying two bricks on both ends of the arch centre line.
  18. Let the mortar harden for 48 hours.
  19. Fill in the gaps around the arch by laying cut pieces of bricks and mortar. Cut these pieces of bricks with a small angle grinder to match the angle of the arch.
  20. Trim away any excess mortar from the arch.
  21. Remove the props and former when the mortar has hardened.

Note: If you want to continue laying the wall upwards so the arch will be surrounded by masonry, continue laying the bricks up to the top of the existing wall.

Please note that all our DIY guides and ‘Expert answers’ advice have been written strictly for reference only. Rated People do not accept any liability for any damage caused to an individual, property or anything else as a result of following our DIY guides and using our ‘Expert answers’ advice.

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