A set of age bands is defined according to Table 2.7 for the purposes of assigning U-values and other data.
| Age band | Years of construction |
|---|---|
| A | before 1900 |
| B | 1900 - 1929 |
| C | 1930 - 1949 |
| D | 1950 - 1966 |
| E | 1967 - 1977 |
| F | 1978 - 1982 |
| G | 1983 - 1993 |
| H | 1994 - 1999 |
| I | 2000 - 2004 |
| J | 2005 - 2009 |
| K | 2010 - 2013 |
| L | 2014 - Onwards |
From the mid-1970s, constructional changes caused primarily by amendments to draft or actual building regulations for the conservation of fuel and power have resulted in increased levels of thermal insulation. The dates in Table 2.7 are generally two or three years after a change in regulations based on indicative figures of likely transition periods. This allows for the dwellings to be completed after the regulations came into force.
Building regulations assign U-values to different building elements as outlined in the following table. This table is for reference only. Default U-values must be taken from Tables 2.21, 2.16, 2.17, 2.14, 2.13 and 2.35.
| Year of regulations | Applicable age band | U-values (W/m2K) | ||
|---|---|---|---|---|
| Roof | Wall | Floor | ||
| 1976 (Draft) | F1 | 0.4 | 1.1 | 0.6 |
| 1981 (Draft) | G | 0.4 | 0.6 | 0.6 |
| 1991 | H2 | 0.35 | 0.55 | 0.45 / 0.6 |
| 1997 | I | 0.35 | 0.55 | 0.45 / 0.6 |
| 2002 / 2005 | J | 0.25 | 0.37 | 0.37 |
| 2008 | K | 0.22 | 0.27 | 0.25 |
| 2011 | L | 0.20 | 0.21 | 0.21 |
As per Table 2.8, the default U-values for existing dwellings for dwellings constructed on or after 1978 (age band F onward) are based on Building Regulations made available from 1976 onwards. Defaults for age bands prior to this generally assume insulation is not present. However, non-default U-values must be calculated when the Assessor has evidence of the construction or makeup of the exposed element. This is particularly important where:
As can be seen from the various tables, the dwelling age band can have a significant bearing on the default U-value. Consequently, it is important that the guidance is followed when determining the dwelling (or extension) age band.
It is preferable to use legal documents (e.g. commencement notice; planning notices):
If legal documents are not available, use evidence from at least 2 of:
If evidence conflicts, err on the side of caution by selecting the “older” option.