0.70mm Building Line

Nothing on a building site is straight without a line. You pull it between two profiles and every block in the course goes to it, you run it across a foundation to set the trench, and you use it with a line level to carry a level across a distance no spirit level will reach.

This one is 0.70mm, a middle weight that pulls up tight without cutting into your fingers or into the block at the corner. A line that is too thin sags in the middle of a long run and gives you a course that dips in the centre. A line that is too thick is hard to pull taut and sits proud of the blockwork. Builder's line also has to take being left out in the sun and the rain between pours, which is why it is sold as a working consumable rather than as string. A roll costs very little next to the time lost to a wall that has to come down again, which is why most builders keep a spare in the box rather than working to a line that has already been knotted three times.