Loft conversion over rear extension

5 Feb 2016
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United Kingdom

I would like some advice as I can not seen to find any on time.

We have a rear full width extension which goes out on ground level to 4m and 3m on the first floor from the original house. Our neighbours house original is set 3m ahead of ours (both are inline at the front) hence why we were allowed a full width on the first floor.

So I would like to add a rear loft dormer.

Under PD we would be allow 50m3 as we are detached however once we have do a hip to gable, we would only get a 7m wide dormer x 3.5m (total width is just under 10m, so leaves 1.5m each side and this leave 0.5m between the rear edge and the dormer) over the original house.

If I was not to go down the PD route would I be allow to have my dormer over my rear extension? Ideally I would like 8m wide x 5.5m (so half over my extended). This would be a half of 93m3 (including the hip to gable of 23m3)

Please let me know your opinions or experiences? Maybe I should do a mix of PD and household. It would be great if someone could point me at some web links on this, as for loft conversions I can only find PD references. The house is within London borough of Redbridge.

Thanks very much.
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I have attached some drawings which shows the original house and then with the rear extension which has been approved (but not yet finished). The blue lines would be the PD allowance which would mean we would have to change the roof over the extension (work has not yet completed to this so not too later), and the green lines is what we want to have, in both cases we plan do have a hip to gable. Please let me know your opinions or experiences. Thanks Donald.
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1. The blue would not be p.d. because it would be physically joined to the roof of the rear extension, which itself was not p.d. To be permitted development, the roof enlargement would need to be completetly separate from the roof of the extension, and it is difficult to see how you could achieve that.

2. I haven't a clue what the planners would think of the green dormer.
Tony, thanks you make a good point re PD, would need to be sign off before the rear extension and completely separate. If we were to go witg the blue scheme we would have to change the roof design of the extension.

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