Which statement about hardboard siding is false?

Hardboard siding is a manufactured product made from wood fibers that are processed and combined with adhesives under heat and pressure, creating a dense material. It is classified as a type of fiberboard, which aligns with the first statement. The thickness of hardboard typically ranges from 5/16 to 1/2 inch, consistent with the third statement. Hardboard is indeed denser than conventional wood siding since it's engineered to have a high density for improved performance and durability.

The incorrect statement regarding its non-combustibility highlights a key aspect of hardboard siding. While it has fire-resistant qualities compared to untreated wood, it is not completely non-combustible. It can still catch fire and contribute to the spread of flames if exposed to a sufficient heat source. Therefore, stating that hardboard is non-combustible is misleading, as it does not reflect the material's actual fire behavior.