FrameTherm 38 Slab is a Glass Mineral Wool slab, designed to improve the thermal conductivity of your home or work environment. It is non-combustible insulation with the best possible Euroclass A1 reaction to fire classification and is manufactured using Knauf Insulation’s unique bio-based binder, ECOSE Technology. The slabs are odourless, rot proof, non-hygroscopic, do not sustain vermin and will not encourage the growth of fungi, mould, or bacteria. These durable slabs when installed correctly have a never-ending life span. FrameTherm slabs contain no ozone-depleting substances or greenhouse gases.

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Key Features:

  • Designed to friction fit between timber studs, which prevents air movement and infiltration through or around the insulation, minimising heat loss.
  • Ready cut to allow quick and simple installation, maximising on-site efficiency when compared with alternative insulants.
  • Non-combustible
  • It is CFC as well as HCFC free
  • Provides thermal as well as acoustic performance.
  • Easy to handle and install
  • Allows for quick and simple installation, maximising on-site efficiency compared to alternative insulants.
  • Extremely durable and long lasting.
  • Awarded the DECLARE ‘Red List Free’ label. No ingredients in the product that are on the red list – including formaldehyde or phenol.

The Knauf FrameTherm 38 Slabs are tightly compact and lightweight which makes storing and handing easy, as well as installing the insulation. For long term protection on site, the product should either be stored indoors, or undercover and off the ground. The slabs polythene packs are designed for short term protection only and they should not be left permanently exposed to the elements. Glass and Rock Mineral Wool product are easier to install than other insulation materials such as rigid boards as their flexibility allows them to adapt to any slight imperfections in the substrate and knit together, eliminating any air gaps. Evidence shows the absence of air gaps is crucial to achieving a high-quality thermal performance.

The Frametherm 38 slab is available in size 570mm by 1170mm to suit spacing commonly used in timber frame applications. The slab provides the best thermal conductivity in the range of just 0.038W/mK. FrameTherm slabs are easily cut to size if necessary, using a sharp blade such as a Stanley knife. A heavy ruler or plank of wood can be used to hold the slab as its being cut, and a mat is recommended to ensure the floor or surface is not scratched when cutting.

Earthwool FrameTherm Rolls and Slabs offer negligible resistance to the passage of water vapour and have a water vapour resistivity of 5.00 MNs/g.m. whilst the frametherm slabs cannot completely soundproof a space they provide excellent sound absorption characteristics.

ECOSE Technology is an innovative, new, formaldehyde free binder technology, centred on rapidly renewable materials instead of petro-based chemicals. It lessens embodied energy and

provides superior environmental sustainability. ECOSE Technology was developed for glass and

rock mineral wool insulation, but offers the same potential advantages to other products where resin-substitution would be an advantage, such as in wood-based panels, abrasives and friction materials.

Knauf FrameTherm Slabs can be installed in a range of methods. These methods include:

  • Timber frame applications – between studs and rafters
  • Pitched Roofs – at rafter level

Safety Certifications:
BS EN 13162, ISO 50001 Energy Management Systems
ISO 14001 Environmental Management Systems
ISO 9001 Quality Management systems
FIRE RATING – Euroclass A1 to BS EN 13501-1

More Information:
Brand: Knauf Frametherm 38 Slab
Length: 1170mm
Width: 570mm
Thickness: 90mm, 140mm
Material: Glass Mineral Wool
Thermal Conductivity: 0.038W/mK


ThicknessThermal ConductivityThermal ResistanceLengthWidthArea Per PackSlabs Per Pack