What are profile boards?

Profile boards are horizontal timber boards fixed to stakes around a building site to mark the exact position and height of the foundation and walls. String lines are stretched between the profile boards so that workers know precisely where to dig and build.

How do profile boards work?

Profile boards are set up at the very start of the building process, before excavation begins:

1. Drive stakes — wooden pegs are driven into the ground at a safe distance from the future excavation
2. Fix boards — horizontal boards are screwed to the stakes, set precisely at the correct datum level
3. Stretch string lines — lines (string or wire) are stretched between the boards to mark the centre lines of the walls
4. Check — a spirit level or laser is used to confirm everything is level and square

Application

Profile boards are essential for:

• House building — setting out the foundation and external walls
• Sheds and garages — even small structures need the foundation set out accurately
• Garden walls — reference points are needed for a straight wall
• Paving — profile boards are sometimes used as a height reference when laying paving

Why not measure in the trench?

The profile boards stand outside the excavation, at a safe distance. This has two advantages:

• They stay in place — the reference points are not lost when the ground is dug out
• Reusable — throughout the build you can re-stretch string lines as often as needed

Materials

• Stakes — timber pegs approximately 50×50 mm, driven 600-800 mm into the ground
• Boards — rough-sawn boards approximately 25×100 mm
• Nails or screws — to fix the boards to the stakes

Related terms

• Centre-to-centre
• Foundation
• Spirit level
• Plumb bob
• Building line

Learn more about building terms in our knowledge base at fredsdiyplans.com.