Permitted development

[Arewehomeyet]

Fir a detached house are 8 m single storey 3 m double storey (with exceptions). But I keep reading conflicting advice about if you do a double storey extension, can the ground floor therefore only be 3 m too to keep within PD? We are meeting architect end of week but I’m really worrying as had wanted to keep everything PD. Does anyone know?

If going double storey, single storey bit cannot be 8m, from what I remember, the footprint rules for first floor applies to ground floor.

So as there is an existing 4 m extension we’ll have to apply for pp? How have I only just realised this 😔

Yes I'm afraid so. Your architect should tell you this when you meet. But extending over existing extensions means that they consider the whole of the existing and proposed as one - so if the ground floor bit sticks out 4m, the whole 2 storey extension is considered to be 4m deep - therefore not PD. Don't be too disheartened, if you're detached you're more likely to get PP as long as it doesn't impact badly on your neighbours.

Any previous extensions are taken into account for pd.