GPDO 2015 Class B Dormer window over new extension

[IG Planner]

I have a client who has built a 2 storey side and rear extension. He has also installed a dormer window across the entire length of the roof of the reformed rear elevation (less than 50 cu m). The rear and side extension had PP but the dormer window did not. He is applying for PP retrospectively to regularise the development as there are a couple of other material amendments. However, the planning officer has advised that they don't normally permit full length dormers and I am wondering whether it benefits from PD rights anyway? The planning officer has quoted condition B2 b) ii) which states that other than in the case of an enlargement which joins the original roof to the roof of a rear or side extension, no part of the enlargement extends beyond the outside face of any external wall of the original dwellinghouse; to argue that planning permission is required. However, my interpretation of this is that this actually allows the built dormer window because the enlarged roof is contiguous with the old roof and therefore now one roof. The planning officer considers that the new dormer extends beyond the outside face of the original dwelling wall and therefore not permitted but my interpretation is that the words 'other than' means an exception where an enlargement to the roof of a rear or side extension is ok. Who is right?

 

[tony1851]

I think your interpretation is correct. The words 'other than' clearly mean that the requirement to not extend over/beyond an original wall does not apply when the roof enlargement extends over a side/rear extension.

(I'm sure that B.2(b)(ii) was only intended to prevent dormers from being built forward of an external wall, where the existing eaves are deeply
projecting, in which case the 20cm rule could in some cases result in the dormer front cantilevering out over the existing wall).

By the way - have you checked the increase in roof volume? The side extension roof will count to the 50m³ limit.