Brick lines are used to create highly-visible layouts for building and masonry work. They are also used as reference lines when laying bricks, helping to keep them plumb and level.
Building layouts
Brick lines are often used to create accurate reference lines prior to doing masonry work like laying concrete for foundations.
Bricklaying reference lines
A brick line is used as a reference point when bricklaying, allowing you to keep your walls level and plumb without having to check with your spirit level every time you lay a brick.
As the wall gets higher, the brick line should be moved up to align with the bricks being laid on the top level.
Laying patio
A brick line can be used as a reference line when laying patio, helping you to keep your slabs and stones straight.
Landscape gardening
Plotting out shapes and borders prior to digging or landscaping can be made easier with a brick line.