What is the purpose of a decorative board at the gable end of a roof?

The purpose of a decorative board at the gable end of a roof primarily serves to enhance aesthetic appeal. This board can provide a finished look to the roofing structure, contributing to the overall design and character of the building. By adding visual interest and complementing the architectural style, it makes the gable end more attractive.

While covering structural rafters can be one function of such boards in some designs, it is not their primary purpose. The main focus is on enhancing the appearance rather than masking structural elements. Additionally, decorative boards are not designed to act as insulation barriers or air vents; they do not contribute to thermal efficiency or ventilation directly. Thus, the most fitting explanation for the use of a decorative board at the gable end is its contribution to the visual aesthetics of the roof and building.