lämpöeristerakenne

Lämpöeristerakenne, literally meaning “thermal envelope structure” in Finnish, refers to the layered system of building skins that together control heat transfer between the interior and the exterior environment. It comprises exterior cladding, weather barriers, insulation, vapor retarders and interior finishes, arranged so that each layer performs a specific function. The primary purpose of a lämpöeristerakenne is to reduce unwanted heat loss or gain, improve indoor comfort, and minimize energy consumption for heating and cooling.

In a typical thermal envelope, the outermost layer is the façade material – for example, brick, stone, metal, or wood cladding – which provides initial weather protection. Beneath it a resilient membrane or house wrap ensures water resistance while permitting vapor diffusion. The next layer typically contains the thermal insulation material; common choices are expanded polystyrene, rock wool, or spray‑polymer foam, selected according to climatic zone, thickness, and desired R‑value. Adjacent to the insulation a vapor barrier may be installed to prevent moisture migration into the structure. Finally, interior drywall or plaster finishes complete the envelope, providing fire rating and aesthetic finish.

The design of a lämpöeristerakenne must account for condensation risk, airflow, thermal bridging, and building codes such as the Finnish Energy Act and Eurocodes. Advanced performance models, such as Heat Loss Calculations (HLAC) or building simulator tools, help architects specify optimal layer combinations. Modern variations include triple‑glazed windows, integrated HVAC ducts, and phase‑change materials that add thermal inertia.

By properly engineering the thermal envelope, builders can achieve significant energy savings, reduce occupant discomfort, and contribute to passive‑house performance or other high‑efficiency certification schemes. Proper maintenance—checking for damaged seals, water infiltration, and insulation degradation—is equally important to preserve envelope integrity over the building’s lifetime.