Arch Building

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Arch building

The arch below is to be rendered.
The arch profile is made from MDF and it is made to suit the window, mark out and cut with a jigsaw.

Here is a sample of arch building, this arch is going to be rendered so its pretty rough and no care was take with the cutting in of the bricks, but it gives you an idea anyway.
The principle is the same if the job is to be face work, just take a little more care when cutting in the bricks to the Voussoirs .

The Voussoirs are the brick on edge header bricks, they are laid in progression as the string line is moved up the wall, they need to worked out in advance so that they fit nicely at the top of the arch and you dont have to cut the last one to fit.

When the arch brickwork has gone off (set), which can be the next day depending on the bricks and the weather conditions, take out the arch profile and make the inside (intrados) of the arch neat.
Scrape off any excess mortar and fill any holes in the joints.

Starting the arch

Holding the arch profile

Starting the arch

Voussoir headers

Progressing up the arch profile

Almost done

Marking Gauge

Measure top

Measure bottom

Marking-Out

Cut

The arch below is to be bagged.
When setting out an arch that is going to be face brickwork, or bagged (bagged brickwork is laid as face brickwork as it will be seen through the bagging) you need to mark out the gauge on the arch profile/template for the voussoirs (pic 1), prior to laying.

Lay the voussoirs in progression up the arch profile as the string line goes up for each course, this will keep the voussoirs in line with everything else.

Cutting in.
When you have to cut a brick to fit.
Measure the distance between the last brick laid that didnt need cutting in the course, and the nearest point of the voussoirs, as in pic 2

Marking out.
In the example, I have measured the top of the brick to determine the gap, which is 170mm, minus 20mm for 2 x 10mm mortar joints at each end(pic2).
Mark this measurement on to the brick,(have the brick oriented the way it is to be laid to avoid any confussion.)

Do the same with the bottom measurement (pic 3) which is 50mm, minus 20mm for 2 x 10mm mortar joints at each end.

When the cut brick is laid it should have an even joint on all 3 sides, as in the picture.

When the arch has gone off, usually the next day, take out the arch profile and clean up the inside of the voussoirs (intrados).