Puurunkoja

Puurunkoja is a Finnish architectural term describing the wooden structural frame of a building—the skeletal timber framework that supports floors, walls and the roof. The word stems from puu (wood) and runko (frame), with the -ja suffix forming a noun.

A puurunkoja comprises primary members such as posts, beams, joists, plates and braces. It is typically made from softwoods like pine or spruce and joined with traditional carpentry methods such as mortise-and-tenon or notch connections, or with modern metal connectors. The frame transfers loads to the foundation and provides attachment points for exterior cladding and interior finishes. In Nordic timber construction, puurunkoja can be used in traditional timber-frame houses as well as in modern light-frame or prefabricated systems.

Historically, puurunkoja has coexisted with other regional building traditions, including log-wall constructions, and has influenced the development of later platform- and balloon-framing approaches. In contemporary practice, it remains central to sustainable timber construction, enabling prefabrication, reuse, and improved insulation when combined with appropriate detailing.

Maintenance and design considerations emphasize moisture control, protection against rot and insects, and maintaining airtightness and thermal performance. The term is most common in Finnish construction literature and may be less familiar outside specialist texts; regional terminology for timber framing can vary.

See also: timber-frame construction, light-frame construction, prefabricated timber.