Lap and panel siding with ventilation elements

A plurality of ventilation elements, vents, slots, or gap elements or similar features that are applied to, or machined into, one or more sides or faces of exterior siding products, such as lap siding, panel siding, vertical siding, horizontal siding, flat (or non-overlapping) siding, flap siding, decorative trim, trim system components or other forms of panels or cladding materials. When the exterior siding product is installed, the ventilation elements, vents, slots, or gap elements or similar features provide a built-in air and water gap to facilitate and increase water drainage and air circulation behind the siding or panel, thereby minimizing water storage in the space behind the product and lowering the equilibrium moisture content of the siding itself. The ventilation features are incorporated into the corresponding product in-line or during the manufacturing process, and do not require any further work during assembly or construction on-site (e.g., furring strips or other similar drainage mechanisms are not needed). Some or all of the ventilation features or elements are located to improve the product's ability to equilibrate (moisture-wise) in a product stack before installation as well as after installation.