The NPPF provides for “the extension or alteration of a building provided that it does not result in disproportionate additions over and above the size of the original building”.
Generally, we would expect that each LPA green belt house extensions policies would typically dictate a certain percentage over the “original house” often around 15 – 30% either in floor space or volume terms.
The term “original house” is critical in that it means the house as originally constructed or as it stood in 1948. Any extension to the original house would need to be taken into account when investigating further green belt house extensions and in many cases, houses have already had extensions larger than the LPA would allow. As will be highlighted in the following examples, this is not always the end of the options.
Understanding the original house and the scale of previous green belt house extensions is critical as a starting point before any design works are undertaken, however, we are often approached once designs have been produced (or even considered by the Council), still with successful results.