How STEICO wood fibre insulation materials are manufactured.

Two processes are used to manufacture wood fibre insulation materials - the wet process and the dry process. In both processes, fresh coniferous wood is broken down by steam and mechanical treatment into individual fibres, which are then further processed.

The wet process

In the wet process, the soaked fibres are formed into panels. Then the panels are calibrated in thickness and dried as whole pieces. The clever bit: in the wet process, the wood's own natural lignin binds the panels. This means that no external adhesives are required, making wet-process insulation boards very eco-friendly and beneficial or your living environment.

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The dry process

In the dry process, the fibres are dried before panel formation. A small amount of binder is applied to the fibres, which are then formed into panels. The clever bit: dry-processed wood fibre insulation panels are lighter and can be produced in greater thicknesses. That is why they are often used to insulate the building envelope, e.g., for above-rafter insulation or facade insulation.

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The main differences in functionality between the two types of boards are density (and consequently thermal conductivity and thermal mass) and ability to transport moisture. Wet-processed boards tend to be better at transporting liquid moisture (capillarity), a property which lends itself to managing moisture very well and so these boards tend to be by far the safest for internal wall insulation situations. Wet process boards also tend to have a higher density which is often simply because to get the required compressive strength they need more fibre in the board. This higher density makes them better at preventing overheating and also better for sound absorption, two of the big benefits of wood fibre insulation but does mean their thermal conductivity is higher.

Dry process boards are often used for roof and timber-framed wall applications as they are tough and can be made in large single thicknesses, usually up to 200mm or so. Because they are less dense than wet process boards they are easier to handle when on a roof, making them safer and preferable. Additionally, the lower conductivity of the boards means lower U-values can be achieved in a given thickness.

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Explore our range of Steico Wood Fibre Insulation products here.