Insulation for a better tomorrow
Timber Frame Walls

Timber Frame Walls

External walls

URSA Timber Frame Rolls and Timber Frame Slabs and are suitable for timber frame walls whilst URSA Hometec Roll 35 is used in lightweight metal stud walls.

URSA TF Roll 32 - thermal conductivity 0.032 W/mK.

URSA TF Slab 32 - thermal conductivity 0.032 W/mK.

URSA TF Roll 35 - thermal conductivity 0.035 W/mK. 

URSA Hometec Roll 35 - thermal conductivity 0.035 W/mK.

Design

URSA TF Roll/Slab is suitable for both timber frame walls and URSA Hometec Roll 35 is used in metal stud walls. They may be used in conjunction with insulated plasterboard internally or cavity insulation (sheathing) to achieve very low U-values.

A vapour control layer is generally required when insulating between the studs, this can either be a polythene sheet (minimum 500g) or a foil-backed plasterboard. When using sheathing insulation the structural frame is maintained at the same temperature as the inside of the building and a vapour control layer may not be required.

The use of both a vapour control layer (internal) and a breather membrane (external) creates an air barrier that helps to improve the air tightness of the building and so limits air infiltration.

Rainwater penetration may be avoided by ensuring the correct use of lintels and cavity trays with appropriate stop ends especially when using sheathing insulation or at changes in the wall construction.

Insulation between the timber or metal studs introduces a series of repeating thermal bridges that must be accounted for in the U-value calculation procedure - the default in timber frame is to use 15% bridged proportion. The addition of internal or external (sheathing) insulation can help to reduce this effect by masking the thermal bridges.

Installation

Insulation between timber studs.

  1. The timber frame, OSB or plywood sheathing, breather membrane etc are all installed in the normal manner.
  2. The external finish of brickwork, tile hanging or external render is then installed.
  3. The URSA TF Roll/Slab is fitted tightly between the studs, normally fully filling the stud depth.
  4. The internal lining of air and vapour control layer (AVCL) and plasterboard are then fixed in the normal manner.
  5. An enhanced U-value may be achieved by installing additional insulation internally or externally to the timber frame. Check with the timber frame manufacturer for specific requirements and details.

Insulation between metal studs.

  1. The metal framing is installed in accordance with the manufacturer’s instructions.
  2. The external finish of brickwork, tile hanging or external render is then installed.
  3. The URSA Hometec Roll is cut to size to suit the stud centres (normally 600mm) and fitted tightly between the studs, fully filling the stud depth.
  4. The internal lining of air and vapour control layer (AVCL) and plasterboard are then fixed in the normal manner.
  5. An enhanced U-value may be achieved by installing additional partial fill cavity wall insulation external to the steel frame. Check with the steel frame manufacturer for specific requirements and details.

Other forms of external finish such as tile hanging, render, timber weatherboarding, PVC-U cladding etc are also suitable and should be fixed in accordance with the manufacturer’s instructions.

URSA Timber Frame Roll 35 U-values

URSA TF Roll 35

U-Value (W/m²K)

Standard Breather Membrane

U-Value (W/m²K)

Reflective Breather Membrane

90mm 0.38 0.32
140mm 0.27 0.24

For further information and more U-values see our technical brochure in the Documents section. Alternatively please contact URSA Technical Department

 

Industry information

Sources of useful additional information

Accredited Construction Details
Linear thermal bridging details
More info
Accredited Construction Details (Scotland)
Linear thermal bridging details
More info

URSA Timber Frame Wall Psi-values

Corner (Normal) – SAP Ref: E16 (Default 0.18 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.06 0.86
TF0003
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.06 0.87
TF0004
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.06 0.85
TF0007
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.06 0.87
TF0008
Corner (Inverted) – SAP Ref: E17 (Default 0.00 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 -0.03 0.97
TF0011
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 -0.04 0.97
TF0012
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 -0.04 0.96
TF0015
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 -0.05 0.97
TF0016
Loft (Gable) (U=0.16 W/m²K) – SAP Ref: E12 (Default 0.48 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.07 0.88
TF0017
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.06 0.89
TF0018
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.07 0.88
TF0019
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.06 0.89
TF0020
Loft (Gable) (U=0.10 W/m²K) – SAP Ref: E12 (Default 0.48 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.08 0.89
TF0021
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.07 0.90
TF0022
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.08 0.89
TF0023
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.07 0.90
TF0024
Loft (Eaves) (U=0.16 W/m²K) – SAP Ref: E10 (Default 0.12 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.08 0.89
TF0025
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.08 0.89
TF0026
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.08 0.89
TF0027
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.08 0.89
TF0028
Loft (Eaves) (U=0.10 W/m²K) – SAP Ref: E10 (Default 0.12 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.10 0.89
TF0029
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.10 0.89
TF0030
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.10 0.89
TF0031
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.10 0.89
TF0032
Intermediate Timber Floor Within Dwelling – SAP Ref: E6 (Default 0.14 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.09 0.93
TF0033
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.07 0.94
TF0034
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.08 0.93
TF0035
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.06 0.94
TF0036
Jamb – SAP Ref: E4 (Default 0.10 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.10 0.83
TF0037
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.07 0.86
TF0038
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.10 0.82
TF0039
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.07 0.86
TF0040
Sill – SAP Ref: E3 (Default 0.08 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.07 0.86
TF0041
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.05 0.88
TF0042
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.07 0.86
TF0043
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.05 0.88
TF0044
Lintel – SAP Ref: E2 (Default 1.00 W/mK)
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.13 0.83
TF0045
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.11 0.85
TF0046
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.12 0.83
TF0047
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.11 0.85
TF0048
Ground Floor – SAP Ref: E5 (Default 0.32 W/mK) Solid Floor. 125mm PUR insulation
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.16 0.85
TF0049
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.16 0.85
TF0050
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.16 0.85
TF0051
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.16 0.85
TF0052
Ground Floor – SAP Ref: E5 (Default 0.32 W/mK) Suspended/Beam & Block. 125mm PUR insulation
Description U-value (W/m²K) Psi-value (W/mK) Temp. factor Download
140mm URSA TIMBER FRAME 32 Standard Breather Membrane 0.26 0.14 0.85
TF0053
140mm URSA TIMBER FRAME 32 Reflective Breather Membrane 0.23 0.14 0.85
TF0054
140mm URSA TIMBER FRAME 35 Standard Breather Membrane 0.27 0.14 0.85
TF0055
140mm URSA TIMBER FRAME 35 Reflective Breather Membrane 0.24 0.14 0.85
TF0056

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