onteltiiliseinien

Onteltiiliseinien is a Finnish term that translates to "hollow walls" or "cavity walls." It refers to a type of construction where two parallel leaf layers of masonry are separated by a gap or cavity. This construction method has been widely used in Finland and other parts of Northern Europe for centuries, particularly in older buildings.

The primary purpose of the hollow wall construction was to provide insulation and moisture management. The air gap within the cavity acts as a thermal barrier, reducing heat loss during cold winters and heat gain during summers. This improved energy efficiency was crucial in climates with extreme temperature fluctuations. Additionally, the cavity allowed for moisture that might penetrate the outer leaf of masonry to evaporate or drain away before reaching the inner leaf, thus protecting the interior structure from dampness and frost damage.

Historically, the cavity in onteltiiliseinien was often left open to the elements at the top and bottom, allowing for natural ventilation. Over time, especially with advancements in building science, these cavities have been increasingly filled with various insulating materials such as mineral wool, rigid foam boards, or loose-fill insulation to further enhance thermal performance. Modern cavity wall construction also incorporates damp-proof courses and ties to ensure structural integrity and prevent moisture bridging. While traditional onteltiiliseinien might have visible ventilation openings, contemporary designs focus on creating a sealed cavity with controlled ventilation systems.