A breather membrane may be required behind fiber cement board in many external wall and façade systems. This guide explains when it is needed, what it does, and what to check before installation.
Modern façade systems are not only about the visible exterior finish. What happens behind the surface is just as important. This is especially true when using fiber cement boards on façades. A properly designed ventilation gap helps the wall system manage moisture, improve drying, reduce trapped condensation, and support long-term performance. Without this gap, even a strong and durable board can be exposed to unnecessary risk.