Abstract: The present invention relates to a wall system which has a solid wood construction on both an inner and outer side with an insulation cavity between, and to an improved building construction utilising the wall system. A plurality of boards is arranged in an interior stack of boards and an exterior stack of boards on a base platform. The interior and exterior stacks of boards are spaced apart by vertical members. The vertical members are spaced apart at spaced locations along the wall. The vertical members have a spanning portion; the interior and exterior stacks of boards are spaced apart by the width of the spanning portion. The vertical members extend across the height of a plurality of boards of each stack of boards.