fylledør

Fylledør is a term used in Norwegian architectural history to describe a door in which the inner space is filled with insulating material rather than being left hollow. The etymology is straightforward: fylle means to fill and dør means door. The filling could consist of various materials such as natural fibers, cork, plaster, or mineral wool, depending on local availability and era.

Design characteristics of a fylledør typically involve a wooden frame with a solid or partially solid core, concealed or faced by panels. The purpose of the fill was to improve thermal performance and reduce drafts, particularly in unheated or poorly heated spaces such as entryways, barns, or servant quarters in historical houses.

Historically, fylledør appeared in rural and agricultural buildings in Norway, especially in cold climates where heat retention was a practical concern. The design varied regionally and over time, and it is often encountered in conjunction with other traditional Nordic wooden construction and plastered surfaces.

In contemporary contexts, fylledør is primarily encountered in heritage restoration, museum collections, and architectural studies. It is not a common term in modern building practice, where standardized insulated doors or solid-core and composite doors are predominant. The concept remains of interest for understanding historical approaches to insulation and the evolution of wooden door construction in Norwegian architecture.