U-values of common UK build-ups
69 wall, roof, floor and glazing build-ups, each with its U-value, worked out by the Wall Build-up Visualiser. The walls, roofs and floors also have their thickness, embodied carbon, a section drawing and the layers. Open any of them in the tool to change it for your project.
Typical UK walls
- Cavity wall, full-fill mineral woolU 0.17 W/m²K · 380 mm · 68 kgCO₂e
- Cavity wall, partial-fill PIRU 0.17 W/m²K · 380 mm · 70 kgCO₂e
- Timber frame, brick cladU 0.19 W/m²K · 344 mm · 57 kgCO₂e
- Timber frame, timber cladU 0.19 W/m²K · 294.5 mm · 24 kgCO₂e
- Solid brick with external insulationU 0.26 W/m²K · 336 mm · 97 kgCO₂e
- Solid brick, uninsulatedU 2.12 W/m²K · 228 mm · 89 kgCO₂e
Typical UK roofs
- Loft roll, 270 mm between and over joistsU 0.16 W/m²K · 282.5 mm · 9 kgCO₂e
- Older loft, 100 mm between joistsU 0.42 W/m²K · 112.5 mm · 6 kgCO₂e
- PIR between and under raftersU 0.14 W/m²K · 252.5 mm · 36 kgCO₂e
- Wood fibre over rafters, mineral wool betweenU 0.17 W/m²K · 294.5 mm · 37 kgCO₂e
- Warm flat roof, PIR over the deckU 0.14 W/m²K · 335.5 mm · 28 kgCO₂e
- Inverted roof, XPS over a concrete slabU 0.26 W/m²K · 438 mm · 119 kgCO₂e
Typical UK floors
Lower-carbon walls
Steel-framed walls
Metal walls
- 01 Sheet metalU 0.19 W/m²K · 386.3 mm · 67 kgCO₂e
- 02 Profiled metal claddingU 0.24 W/m²K · 181.2 mm · 38 kgCO₂e
- 03 Composite panelsU 0.22 W/m²K · 101 mm · 44 kgCO₂e
- 04 Metal rainscreensU 0.23 W/m²K · 340 mm · 94 kgCO₂e
- 05 Mesh screensU 0.22 W/m²K · 306 mm · 90 kgCO₂e
- 06 Louvre screensU 0.24 W/m²K · 531 mm · 93 kgCO₂e
Glass walls
Concrete walls
Masonry walls
Polymer walls
Timber walls
Metal roofs
Glass roofs
Concrete roofs
Timber roofs
Polymer roofs
Fabric roofs
Real-life projects
Systems 01 to 44 follow the list in Modern Construction Envelopes by Andrew Watts. The build-ups are generic examples.
Figures come from the Wall Build-up Visualiser's own calculation, with generalised values for typical products, for an England new home with default settings. They are indicative, for design and teaching: check the manufacturer's declared values and the current regulations for your project. Rules and standards last checked 21 October 2026.