What are furring strips?
Thin wood or metal strips installed against a wall or sheathing to create a level nailing surface for siding and allow water drainage and air circulation in the gap between the wall and siding.
Furring strips are narrow strips of wood or metal fastened to an exterior wall or rim to provide a flat, level surface for attaching siding materials. In Lake County and other humid Florida regions, they serve the critical function of creating an air gap, or rain screen, between the siding and the underlying wall structure.
The spacing they create allows water that penetrates the siding to drain downward and out behind the system rather than pooling against the sheathing or framing. This is especially important in Florida's climate, where moisture and humidity accelerate wood rot, mold growth, and structural damage. Without that air gap, trapped moisture can compromise both the siding and the wall behind it.
Contractors typically use 1/4-inch to 1/2-inch strips, though the exact thickness depends on the siding type and the wall condition. Pressure-treated lumber is common for wood strips due to humidity exposure, while metal furring (often aluminum) resists rot entirely. The strips are nailed or screwed at regular intervals, usually 16 inches on center, to keep them from bowing.
In renovation work, furring strips also solve the problem of an uneven or damaged wall surface. Rather than removing the existing substrate, installing strips creates a uniform plane, allowing new siding to sit flush and true. This approach saves time and expense while providing the ventilation and drainage benefits that extend the life of both siding and structure in Florida's wet climate.