A carpenter is installing pre-finished wood siding. The manufacturer's instructions specify a minimum 2 mm ventilation gap behind the siding. What is the most common and effective method to achieve this specific ventilation requirement?

Question: A carpenter is installing pre-finished wood siding. The manufacturer's instructions specify a minimum 2 mm ventilation gap behind the siding. What is the most common and effective method to achieve this specific ventilation requirement?

Answer options:

• Install the siding directly over the WRB and rely on its texture. ✅ Use furring strips (strapping) installed vertically over the WRB.
• Apply a continuous bead of sealant behind each siding board.
• Install a second layer of sheathing to create the gap.

Correct answer: Use furring strips (strapping) installed vertically over the WRB.

Explanation: To create a defined ventilation gap behind siding, especially thicker materials like wood, furring strips (often called strapping in Canada) are installed vertically over the WRB. This creates a continuous air space for drainage and drying. Relying on WRB texture, sealants, or a second sheathing layer are not appropriate methods for achieving a controlled ventilation gap.