1) Building material for walls 
Beaverboard (also beaver board) is a fiberboard building material, formed of wood fibre compressed into sheets. It was originally a trademark. It has occasionally been used as a canvas by artists; most famously, the iconic painting American Gothic (1930) by Grant Wood is painted on a beaverboard panel. ...
a light, stiff sheeting made of wood fiber and used in building, esp. for partitions or temporary structures.