Insulation ~ Glass Fibre

Similar to mineral wool insulation, glass fibre is one of the most common forms of insulation in the UK – everyone knows that rough, itchy, scratchy feel of glass fibre much beloved in our drafty attics. Whilst it has been installed in many homes for at least of couple of decades, this has not usually been done to the same thickness that would now be recommended so a top-up may be in order.


Glass fibre manufacture involves melting the raw materials (which typically include around 50% recycled glass) in a furnace at temperatures in excess of 1500ºC. The resultant molten glass is thrown by centrifugal force to form filaments. These filaments are then aggregated together and the resulting mat of fibres is coated with a resin to bind them together. The resin is then cured in an oven and the mat cut into blankets that can be rolled and packaged.


  • High embodied energy.
  • Fire proof.
  • The fibres can be an irritant.
  • Versatile and relatively easy to fit.
  • Relatively low cost.

Blocks of glass fibre have a K value in the order of 0.05 W/m.K. (Watts per meter Kelvin ~ a lower value is a better result)

Cheap … expect to pay under £2 per square metre including VAT.






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