Timber Frame Walls Built In
Timber Frame Wall Insulation
Knauf Insulation Timber Frame Wall Glass Mineral Wool and Blown insulation


Timber frame walls generally provide better levels of thermal insulation performance than masonry walls of comparable thickness. However, the reduced mass of the wall means that insulation materials need to provide a higher level of acoustic performance to compensate.

Mineral wool insulation is friction-fitted between timber studs, with the option to install additional insulation to the interior face of the wall, and / or into the cavity to further enhance thermal performance. 

Insulation is blown-in between timber studs and behind a
veil, with the option to install additional insulation to the
interior face of the wall, and / or into the cavity to further
enhance thermal performance.



Why Mineral Wool?

  • Mineral wool friction-fits between timber studs,  losing joints and preventing air movement and infiltration through or around the insulation, minimising unwanted heat loss.

  • Mineral wool solutions are much quicker to install than rigid foam boards which require accurate cutting, improving speed and efficiency of installation.

  • Provides a perfect intimate contact between frames, offering a full-fill solution for all stud depths, centres and void shapes, ensuring maximum thermal and acoustic performance is maintained.

  • Can be installed either on-site or can be factory installed using our innovative Supafil Frame System, specially developed for off-site manufacturing processes, minimising waste, reducing labour demand and improving overall production efficiency.

Download our Solutions Guide  Download our Timber Frame Walls PDF

Typical U-values
Using Earthwool FrameTherm Rolls between timber studs + 50mm Knauf insulated plasterboard internal lining

Stud Thickness (mm)Product UsedMasonry Outer Leaf (Cavity unventilated)Tile/timber clad outer leaf (Cavity ventilated)
140Earthwool FrameTherm Roll 320.170.18
140Earthwool FrameTherm Roll 350.180.19
140Earthwool FrameTherm Roll 400.190.20
90Earthwool FrameTherm Roll 320.220.23
90Earthwool FrameTherm Roll 350.230.24
90Earthwool FrameTherm Roll 400.240.25

Notes: Timber bridging is assumed as 15% and the stud depth is taken to be the same as the thickness of insulation specified. Thermal conductivity of timber studs is 0.12W/mK. Ventilated low emissivity airspace assumed to increase the R-value of the cavity to 0.29m2K/W and unventilated low emissivity airspace assumed to increase R-value of cavity to 0.77m2K/W. Knauf Insulated Plasterboard comprises 9.5mm plasterboard facing at 0.19W/mK where the remainder of the thickness is insulation with thermal conductivity of 0.023W/mK.

Typical U-values
Using Supafil Frame between timber studs


Stud Thickness (mm)Vapour permeable membraneMasonry Outer Leaf Tile/timber clad outer leaf 
200Low E0.180.21
140Low E0.230.27

NOTE: Low E membrane used in the above calculations = Protect TF200 Thermo. U-values calculated assuming Supafil Frame installed density of 30kg/m3 and having thermal conductivity of 0.033W/mK.

Typical U-values


ApplicationAngle range (o)Thermal conductivity (W/mK)Installed density (kg/m3)
Enclosed rafter spaces0-250.03819.0
Enclosed rafter spaces and timber frame stud walls0-900.03623.0
Enclosed rafter spaces and timber frame stud walls0-900.03426.0
Enclosed rafter spaces and timber frame stud walls0-900.03330.0


For any U-value calculations for alternative construction build-ups, please contact our Technical Support Team on 01254 503571.
For written U-value calculations, please complete our contact form by clicking here, including details of your full through construction build-up and we will respond accordingly to meet your requirements.