The present disclosure relates generally to wallboards, for example, suitable for use in constructing internal walls. The present disclosure relates more particularly to a wallboard and a method that provides simplified high-quality surface finishing. The wallboard includes a wall panel having a front surface and a rear surface. A sandable coating is disposed on the front surface of the wall panel. The method includes positioning wallboards adjacent to one another, applying sandable joint compound over joint formed between the wallboards, and sanding the joint compound and the sandable coating of the wallboards.