When building masonry, the key to creating an attractive, professional product is keeping each course of bricks level and true. You can do this is using an ordinary spirit level, but levels have disadvantages. The level must be kept within reach and used frequently, requiring that you lay down other tools. It must remain relatively clean and be handled gently, which can be a challenge on a job site. Wood line blocks offer an alternative that continuously checks both level and true of a course of brick, but keeps your hands free and your job moving.
Establish a level foundation for the brickwork. If you are building a wall, then this will be a concrete footer, formed and poured in an excavated trench. The exact specifications of the footer will be determined by local building codes and the dimensions of your wall. The higher the wall, the deeper and wider your footer will be.
Set up mortar boards along the length of the wall if it is more than a few steps from the mixer to your work area. Leave a generous couple of shovels of fresh mortar on each of them. This will allow you to keep working at a steady pace, refilling your hand-held board from them.
Bed the first course's corner bricks in mortar, firmly seating them with a tap of the trowel or shovel handle.
Fit wood line blocks to the outside of each corner brick and stretch nylon string between them. Secure string in the blocks' grooves. The string line provides a reference for laying the course bricks level and true.
Tighten the line as much as possible without moving the corner bricks out of their position.
Lay the course of bricks so the line remains in the same position relative to the face of each brick laid.
Continue with each new course of bricks, by laying corner bricks and moving wood line blocks up.
Re-tighten the line and continue laying each new course.
Building corners up a few courses above the one on which you are currently working will help the bricks supporting the wood line blocks remain stable and in position.
Concrete mortar contains lime, which can be very irritating to the skin. Wear protective clothing and wash promptly if concrete contacts skin.