Make Wooden Line Blocks for Block Walls Instead of Nailing Up Scrap

The Problem

Laying block to a string means re-fixing the line at every course, and the improvised rig — a scrap of wood with two nails to wrap the line around — has to be nailed, unwrapped, and re-nailed every time the line moves up. It's slow, and a nailed line is never quite at the block edge where you want it.

The Technique

Make a pair of line blocks from wood scraps, sized to your masonry unit:

1. Cut a block with a slot that fits over the corner of your masonry unit — the fit depends on the block you're laying, so size it to yours.
2. Cut a kerf where the line will sit: hook the string into it and the tension of the stretched line clamps the block against the corner. No nails — tension is the fastener.
3. Leave a horn on the block for winding the surplus line, so you always carry a working length to the next course.
4. In use: hook a block over each end of the course, stretch the line between them, and set a line stretcher or adjuster where needed. To move up a course, unhook, move, re-tension — seconds instead of minutes.

The line stays exactly at the unit's edge, every course, end to end of the wall.