Industrially produced wood fibre insulation was introduced around twenty years ago after engineers from the timber producing areas of Europe devised new ways of transforming timber waste from thinnings and factories into insulation boarding.

The success of wood fibre insulation derives from an attractive environmental profile combined with a whole bag of functions including rigid insulation, sheathing and sarking for timber frames, roofs and flooring as well as flexible insulation for studs and rafters.

Wood of course is renewable, it sequesters carbon during its growth and product production is relatively free from pollution. The insulation value of wood fibre boards is not as dimensionally efficient as some of the orthodox petro-chemical materials - but it's no slouch either - typically coming in with a 'k value' range of between 0.038-0.043 W/mK depending on format. That high u-values are obtainable can be seen from such as an example as the 'Larch House', the social housing prototype designed by Bere Architects which won Passivhaus certification - achieved, in part, using wood fibre insulation.

Other features include 'breathability' that helps moisture to be regulated as well as a material density suffice to add a degree of decrement delay that will be useful for all those hotter summer days ahead of us in the south of England.

Worth pointing out is that manufacturers tend to market wall or roof 'systems' that include the insulation as well as other elemental components. The advantage of considering the use of these is that the construction types have already been 'tried and tested'.

Common formats

Wood fibre insulation can be designed to deliver a range of functions through varying to some degree both manufacturing technique and board ingredients.

	Flexible insulation Application: Friction mounted between studs / rafters Thermal conductivity: circa 0.038 W/mK Density: circa 50 kg/m3 Water vapour / diffusion resistance: circa _ Thermal capacity: circa 2100 J/kgK Composition: Wood fibres, polyamide (binding fibre), ammonium phosphate (flame retardant) Production method: Dry process
	Weather resistant insulation for sheathing and sarking Application: Walls and roof Thermal conductivity: circa 0.043 W/mK Density: circa 180 kg/m3 Water vapour / diffusion resistance: circa 3 Thermal capacity: circa 2100 J/kgK Composition: Wood fibres, PMDI glue (isocyanate), paraffin wax, latex Production method: Dry and wet processes
	Renderable insulation for walls Application: External walls Thermal conductivity: circa 0.042 W/mK Density: circa 140 kg/m3 Water vapour / diffusion resistance: circa 3 Thermal capacity: circa 2100 J/kgK Composition: Wood fibres, PMDI glue (isocyanate), paraffin wax, latex Production method: Dry and wet processes
	Load-bearing & water resistant insulation for below floor screeds Application: Below floor screeds (also roof and walls) Thermal conductivity: circa 0.042 W/mK Density: circa 140 kg/m3 Water vapour / diffusion resistance: circa 3 Thermal capacity: circa 2100 J/kgK Composition: Wood fibres, PMDI glue (isocyanate), paraffin wax, latex Production method: Dry and wet processes

Other common ranges: 'Universal', usually applied in conjunction with other wood fibre insulation types. Most manufacturers will supply more than one type of 'Universal' board, each providing for different performance characteristics.
 

+ / - for wood fibre insulation

	Typically contains high percentage of post-industrial waste material
	Manufactured from renewable resources
	Reusable if in a suitable condition
	Recyclable
	Compostable or can be used in energy recovery
	Sequesters CO2 during tree growth
	Hygroscopic – provides a degree of humidity control
	Decrement delay
	Paraffin wax water repellent is a petrochemical derivative
	High embodied energy
	Usually imported from the continent which adds to embodied energy
	Rigid boards can be fragile and difficult to use on site

Disclaimer

GreenSpec accepts no responsibility or liability for any damages or costs of any type arising out of or in any way connected with your use of this web site. Data and information is provided for information purposes only, and is not intended for trading purposes. Neither GreenSpec nor any of its partners shall be liable for any errors in the content, or for any actions taken in reliance thereon