The Royal Society of Architects in Wales (RSAW) picked Silver House on Gower as building of the year and The Chickenshed in Trellech, Monmouthshire, won an award in the special category.
These buildings were picked from a shortlist of four.
Judges described Silver House as a "very elegant and thoughtful piece of architecture".
Silver House was designed by Hyde + Hyde Architects while The Chickenshed, a holiday home, was designed by Hall + Bednarczyk Architects.
The Chickenshed was described as "very simple and elegant" by the judging panel when the winners were announced at Cardiff and Vale College on Tuesday.
A converted chicken shed and a family home have picked up prizes at the Welsh Architecture Awards.