Construction Performance Guidelines
4.1 To measure the variation:
- Place two blocks of equal thickness on either side of the surface you are considering.
- Stretch a string across the top of the blocks so the string doesn’t sag; the blocks may have to be secured from moving.
- Measure the difference between the string and the actual surface and subtract the thickness of the blocks.
- Compare the result with the allowable variation in the Guidelines.

4.2 Approximate width measurements specified in this document:
In order to quickly assess whether a defect is within the specified tolerances, the following Canadian coins may be used to approximate measurements of variation.
