Rear extensions in Lisburn and Castlereagh

1,887 applications since 2016. 1,778 approved and 19 refused. Refused: about 1 in 95 here, about 1 in 7 across the councils we cover.

Last updated 8 November 2026.

Without planning permission

Up to 3 m deep on a terrace or semi, 4 m on a detached house
Up to 6 m or 8 m through the neighbour-consultation route, not on protected land
No higher than 4 m, and eaves no higher than 3 m within 2 m of a boundary
Together with other buildings, no more than half the garden and grounds
Materials similar in appearance to the house

England, houses only. Flats, listed buildings, conservation areas and Article 4 directions change this. The full rules.

Year	Applications	Approved	Refused
2026	136	81	1
2025	135	127	2
2024	134	130	0
2023	145	135	2
2022	160	155	2
2021	271	264	2
2020	169	166	2
2019	191	185	2
2018	168	162	2
2017	191	187	3
2016	187	186	1