Knauf SteelTherm 40 Roll is a lightweight, flexible, and resilient, non-combustible glass mineral wool roll designed for thermal insulation of external walls in steel frame construction applications. The roll provides great thermal conductivity as well as excellent sound absorption characteristics. SteelTherm Roll 40 has a zero Ozone Depletion Potential and zero Global Warming Potential and poses no threat to the environment.

The SteelTherm roll is manufactured in 600mm widths and specifically designed for friction fitting between standard light steel frame studs. The roll is available thicknesses 100mm and 150mm with thermal conductivity of 0.040W/mK. Knauf SteelTherm Roll 40 is lightweight and easy to handle and install and easily cut to size if required. Providing the SteelTherm rolls are installed correctly, they should last for as long as the relevant building does.

Showing all 2 results

Filter by Brand
Filter By Roll Thickness

Key Features:

  • Designed specifically for steel frame construction
  • Sized to friction fit between steel studs at 600mm centres
  • Easy to deliver and handle
  • Quick and simple to apply
  • Lambda 0.04 W/mK
  • Sound absorption characteristics
  • Non-combustible
  • Durability and long-lasting

Earthwool SteelTherm Roll 40 is odourless, rot proof, non-hygroscopic, does not sustain vermin and will not encourage the growth of fungi, mould, or bacteria. Vapour resistivity Earthwool SteelTherm Roll 40 offers negligible resistance to the passage of water vapour and has a water vapour resistivity of 5.00MNs/g.m.

Knauf Earthwool SteelTherm Roll 40 is supplied in polythene packs which are designed for short term protection only. For long term storage, the rolls should be stored indoors, above ground level. If indoor storage is not an option, the required weatherproofing materials should be applied to protect the product. Earthwool SteelTherm Roll 40 should not be left permanently exposed to the elements.

Knauf Insulation mineral wool products made with ECOSE Technology benefit from a no added formaldehyde binder, which is up to 70% less energy-intensive than traditional binders and is made from rapidly renewable bio-based materials instead of petroleum-based chemicals. The technology has been developed for Knauf Insulation’s glass and rock mineral wool products, enhancing their environmental credentials without affecting the thermal, acoustic or fire performance. Insulation products made with ECOSE Technology contain no dye or artificial colours

Knauf SteelTherm Slabs can be installed into:

Wall Applications: friction fitting between standard light steel frame stud

Light steel frame wall insulation:

Light steel framing is extensively used due to its good thermal and structural behaviour. Heat loss reduction and thermal comfort have been the main driving forces defining the size of the frames. When using this form of construction, it is important that some insulation is placed inside or outside the steel frame to provide a thermal break and avoid condensation.

Safety Certifications:

BS EN 13162, BS EN ISO 50001 Energy Management Systems
OHSAS 18001 Occupational Health and Safety Management Systems
ISO 14001 Environmental Management Systems
ISO 9001 Quality Management Systems

More Information:
Brand: Knauf SteelTherm Roll 40
Length: 5.55mm, 8.65mm
Width: 2x600mm
Thickness: 100mm, 150mm
Material: Glass Mineral Wool
Thermal Conductivity: 0.040W/mK


Thickness (mm)Thermal Conductivity (W/mk)Thermal Resistance (m2K/W)Length (m)Width (mm)Area Per Pack (m2)
1500.0403.755.552x 6006.66
1000.0402.508.652x 60010.38


Installing Knauf SteelTherm 40 Roll into Light Steel Frame Walls

Benefits of light steel frame wall construction:

  • Quick erection of the structural frame and early creation of a dry envelope, thus removing the external finish from the critical path enabling an early start on the internal fit out.
  • Wet weather does not interrupt erection process.
  • Lightweight structure reduces load on foundations, especially important on brownfield sites and roof top extensions.

Knauf SteelTherm can be cut easily using a sharp blade. A mat is recommended to place below the rolls whilst cutting.

Typical Construction:

Inner Leaf comprising of a double layer of standard plasterboards, a vapour control layer and Earthwool SteelTherm Roll 40 or Earthwool Flexible slab between steel studs and PIR insulation board sheathing. A range of cladding can be applied, including an outer brick skin or terracotta rainscreen cladding.


The SteelTherm rolls are friction fitted between the steel studs as standards centres and are self-supporting.

A vapour control layer is taped to the studs across the inner face of the walls before applying the plasterboard with the necessary fixings. The vapour control layer should be free from holes. Any tears should be repaired and gaps, overlaps and apertures should be fixed and effectively sealed. Take the necessary care around electrical boxes.

The foil-faced PIR insulation boards are held in place by the steel framing used to support the outer cladding on temporarily fixed with suitable self-tapping screws and washers. secondary fixings may be used where required.

Cavity barriers will have to be installed between the frame and the brickwork or suitable intervals to the full depth of the cavity.

With light steel frame construction, a vapour control layer is essential on the warm side of the insulation to reduce the risk of interstitial condensation forming. Where a foil faced insulation board is used on the outside of the steel frame, it is particularly important to ensure that the vapour control layer is continuous and not punctured by services.

Fire precautions are necessary with light steel frame construction.

  • Cavity barrier and fire stopping must be provided at junctions with other elements in accordance with the requirements of national building regulations.