Pekka Heikkinen, head of the project and professor at the Aalto University, said: "When you take a house to a competition as far as Madrid, you don't want to settle for the second best in materials.
"Thus, we are pleased to be able to use UPM's high-quality spruce timber and plywood for this project."
UPM's Facade, a slow-grown, live-knotted homogenous whitewood, will be used for the wooden cladding of the building and the company's timber products will be used in the roof and floor structures.
The competition began on 18 June and runs until 27 June in Madrid.
Solar Decathlon Europe is an international competition among universities that aim to advance knowledge of industrialised, solar and sustainable housing.