Eristyskerroksen

Eristyskerroksen (insulation layer) is the layer of insulating material incorporated into a building envelope to reduce heat flow between interior and exterior environments. It is commonly placed in exterior walls, roof assemblies, floors above unheated spaces, and foundations, and may be used in both new construction and renovations. The primary purpose is to improve energy efficiency, maintain comfortable indoor temperatures, and reduce heating and cooling costs. It also affects acoustic performance and, depending on the material, fire resistance and vapor control.

Materials vary widely. Mineral wool and glass wool provide fire resistance and moisture tolerance; polystyrene boards (expanded or extruded) offer high insulating value with low thickness; polyurethane or polyiso foams can provide high R-values in compact layers. Cellulose, natural fibers, and aerogels are used for specialty applications. The choice depends on climate, structural considerations, moisture conditions, and code requirements. Some materials require a vapor barrier or vapor-permeable membranes, and many installations include an air barrier and moisture control strategy.

Design and installation considerations include achieving continuous insulation to minimize thermal bridges, proper detailing at joints, penetrations, and edges, and ensuring effective air sealing. Thickness and material selection are influenced by climate, energy codes, and desired energy performance, with higher performance layers allowing thinner builds in some cases.

In Nordic and other cold climates, eristyskerroksen plays a central role in energy efficiency, often combined with efficient windows, airtight construction, and ventilation systems to manage indoor air quality. The term is the Finnish label for the insulation layer in a building envelope.