The River Avoca is a fast flowing river that crosses Southern Wicklow, where the sheltered climate along its valley supports some exceptional gardens. This site, west of Ballinaclash town, has a wonderful southern aspect to the river as well as extensive overgrown mill and millrace ruins. The house HRA designed for the site is situated to enjoy a cantilevered view of the river and the mill. The prefabricated building is organised on a square grid of fine steel columns at four metre centres. Walls and floor plates are also to be installed as storey-height prefabricated units. The one-storey house has an intensively planted roof to reduce the visual impact to the adjacent road which is level with the roof. Three bedrooms are arranged to the back of the house while the living dining areas enjoy 270 degree views of the river as it sweeps past. Three small atriums provide solar gain and controlled ventilation to the plan as well as offering further spatial connections and short cuts between living functions.