Roofspace under PD with existing extension

[Deet]

Hi - hoping someone can help.

I live in a bungalow which already has a ground floor extension at the rear of the property. The roof of this joins to the original roof.

I'm now looking to get a hip to gable + dormer at the rear (hopefully under Permitted Development). It's likely any dormer at the rear would end up joining to the ground floor extension roof.

The extra roof space volume allowed under PD would be 50 cubic metres - I'm wondering how much of my ground floor extension would count to towards this as 'roof space'? Would it be just the space above the ceiling (i.e. a toblerone shape).

I also have a conservatory next to the extension, does any of this count towards 'roof space' under PD?

 

[DevilDamo]

Any new roof space that connects to the original roof would count towards your allowance.

 

[^woody^]

Hip to gable under PD as that it's the contentious bit, then apply for the dormer if need be.

Just make sure you are correctly calculating 'additional' roof volume. The conservatory would not normally count.

 

[Deet]

Thanks both!