A residential building requires a foundation setback of 4.0 metres from the property line as per municipal zoning bylaws. The survey pins for the property line are 150 mm square steel pipes. How should the carpenter mark the excavation limit relative to these pins, assuming no offset for formwork thickness initially?

Question: A residential building requires a foundation setback of 4.0 metres from the property line as per municipal zoning bylaws. The survey pins for the property line are 150 mm square steel pipes. How should the carpenter mark the excavation limit relative to these pins, assuming no offset for formwork thickness initially?

Answer options: ✅ Measure 4.0 metres inwards from the face of the survey pin closest to the building, plus account for pin thickness.

• Measure exactly 4.0 metres from the center of the survey pin.
• Measure 4.0 metres outwards from the survey pin.
• Mark the excavation 3.850 metres from the property line.

Correct answer: Measure 4.0 metres inwards from the face of the survey pin closest to the building, plus account for pin thickness.

Explanation: Setbacks are typically measured from the property line itself. For a 150 mm square pin, 75mm (half the thickness) of the pin extends past the actual property line. To ensure a 4m setback from the property line, one would measure 4.0 m + 0.075 m = 4.075 m from the building-facing edge of the pin, or 4.0 m + half the pin thickness from the outer edge of the pin to the property line, then an additional 4m to the excavation limit. The critical point is interpreting 'from the property line' and how the physical pin represents it, ensuring the measurement is from the true property boundary. So, 4.0m from the property line and you should account for the pin thickness.