Do I Need Planning Permission.co.uk
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Hi, I have a rear extension thats been there for many years that backs onto a lane at the rear of the house.
The height from the lane floor to the ridge of the gable end is 3 metres.
My question is, if I built up the walls to the height of the ridge and replaced the badly leaking roof with with a flat roof could this be done within permitted development?
Also, could I go up another metre to 4 metres?
The ground floor at the garden side of the building is about two feet lower than the back lane. Would the height measurement be from the lowest floor point or the highest?
https://pasteboard.co/n8GBgf6FY6OT.png
https://pasteboard.co/cAMtodSd6CTB.png
Thanks for any thoughts.
Mike

Because of how close the building is to a boundary, the overall height of the flat roof cannot exceed 3m. The height is taken from the highest ground level adjacent to the structure.

On another note, the relationship between the structure and the lane may also be an issue as it may be seen as a highway.

If in doubt, submit a Planning application.

Hi Damian,
Thanks for your advice. When you say overall height is this to the highest point. I read that the maximum height is to the eaves but I am not sure where the eaves are on a flat roof?
You can see from the state of the lane that it is unadopted which I am assuming means it is not a public right of way?
Thanks again
Mike

The eaves height of a flat roof is the top of the flat roof finish. You’ll find that on Page 12 of the Permitted Development Technical Guidance document.

Just because it’s unadopted does not discount it as a highway. It can be used by people or vehicles so meets the requirements for a highway.