The site was the location of an underground Yorkshire Water reservoir which had outline planning permission for three detached houses.  Our client purchased the site at auction with the intention to build a single German kit built home for himself and his wife.  The underground reservoir was of concrete construction with columns dividing it into bays, each with a barrel vaulted roof.  We worked with the kit supplier in Germany to obtain the layout that our client wanted and the integration with the basement created in the reservoir.  A hole was cut in the reinforced concrete top for the staircase to pass through and the contractor dug down the side to cut a hole in the side to create a sunken patio and external access.  The basement contains an additional bedroom, bathroom, games room and plant room.  The plant room contains the cylinder and pump that controls the ground source heat pump & whole house ventilation system with heat recovery.  Other renewable energy technologies include solar PV panels on the garage roof.