Construction Supervisor License Practice Exam

Timber footings are to be treated unless placed entirely below which line?

1. Bedrock

2. Constant water table

3. Support type V construction

4. Permanently fresh water line

The correct answer is: Permanently fresh water line

Timber footings are required to be treated to prevent decay and damage from insects and moisture exposure. However, when they are placed entirely below the permanently fresh water line, they are submerged in water that is consistently fresh, which significantly reduces the risk of deterioration. In such an environment, the footings remain in a constant state of saturation, protecting the wood from the dry conditions that typically contribute to decay. In contrast, the other options focus on varying conditions that can lead to potential decay issues. Bedrock does not offer moisture protection like fresh water does; the constant water table can fluctuate, possibly exposing timber to air and moisture that could foster decay; and support type V construction pertains to a building classification which does not directly influence the treatment requirement for timber in footings. This makes the depth below the permanently fresh water line the definitive factor for exempting timber from treatment, safeguarding its integrity when placed in that specific condition.