6.1.4 Fabric Values for ‘notional’ building in Scotland
The following tables include the standard package of construction performance measures for the notional building:

U-Values
Exposed Element U-Values (W/m2K)
Pitched roof 0.16
Flat Roof 0.25
Walls 0.30
Floors including ground floors 0.25
Windows, rooflights and doors 2.2
Display windows 5.7
Vehicle access and similar large doors 1.5

The U-values (area weighted average U-values) for column b of the table to this clause are summarised in the diagram below. The extension is the shaded portion, the existing dwelling is in elevation behind.