A three-storey residential building constructed with wood framing is being clad with fibre cement siding. The manufacturer's instructions specify a minimum 25 mm air gap for the rainscreen system. What is the most common and effective method to achieve this specific air gap behind the cladding?

Question: A three-storey residential building constructed with wood framing is being clad with fibre cement siding. The manufacturer's instructions specify a minimum 25 mm air gap for the rainscreen system. What is the most common and effective method to achieve this specific air gap behind the cladding?

Answer options:

• Install thinner sheathing to create space.
• Shims every 600 mm on centre behind the siding. ✅ Continuous furring strips attached to the exterior of the WRB.
• Apply a thick coat of stucco over strapping.

Correct answer: Continuous furring strips attached to the exterior of the WRB.

Explanation: Continuous furring strips, typically wood or composite, installed vertically over the WRB, are the standard method for creating a consistent air gap in a rainscreen system. Shims would be inconsistent and less reliable, and thinner sheathing or stucco over strapping are not direct methods for achieving a precise air gap for fibre cement siding.