Planning departments have a scary reputation in some towns. We all know stories, hopefully told to us rather than experienced by us, of planners refusing to grant permission to applications that sound reasonable and straightforward. So far, at Inside Out Oxford, we have not had an application refused. We don’t know for sure, but we like to think that’s because our designs are attractive and sympathetic to the surroundings, and because our project descriptions use wording that helps to sell the intent. Garden rooms used as annexes for a retired parent, for example, help families to stay together affordably and take the load for care off the state. You can pitch that persuasively and appealingly, or miss a trick and not even mention it. And remember, garden rooms are here to stay, post-pandemic. Hybrid working both from home and in the office is much more likely to be the norm for most businesses that can afford that, and nobody likes to set up office in the kitchen, or a child’s bedroom.

Hi, It depends on whether the works fall under Permitted Development (PD). If they do then you can in theory have a max height of 4m to a parapet and 3m to the eaves (flat roof level essentially). See page 17 and then page 12 on the linked doc below). These dimensions are from the natural ground level, not the finished floor level. Note, there maybe be Rights to Light issues with a 3/4m high wall on the boundary that sits outside of planning. However, if you have submitted a Householder planning application the PD rules do not apply and the LPA can stipulate what they feel is appropriate in terms of impact on neighbours and other issues such as design. This is perhaps where the 2.5m height restriction has come from. It is not terribly unusual. You should be able to get 2m internal headroom. We often back the full-height kitchen cabinets up against these walls to hide the lower appearance along this edge. Then by the time the roof slope travels over the 600mm kitchen unit depth the height of the ceiling is around 2260mm which does not look too low.https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/830643/190910_Tech_Guide_for_publishing.pdf Please let me know if I can be of further help, Carl

Flats unfortunately don’t have the same Permitted Development Rights (PDR) as houses so i think you’d need planning (the same for houses if it’s listed, in a Conservation Area or if there’s an Article 4 Direction in place which removes PDR). I assume there are also a lot of Conservation Areas in Camden anyway! are you freehold or leasehold as you may also need permission from them?

No but you cannot use his wall. That would be a tresspass. You need to build all 4 walls on your property. If it's the wall to his house then party wall regs might apply depending on the depth of your foundations.