Planning application

[onix]

Hi everyone,
I'm planning to carry out some renovations on my terraced house in London and could use some advice on the planning application process. Specifically, I'm looking to do a loft conversion and also create an open plan kitchen.
Does anyone know if it's generally cheaper to submit one planning application covering both projects, or would be the same cost to submit two separate applications? Any insights or experiences you can share would be greatly appreciated!
Thanks in advance!

If the kitchen is internal work only, you won't need planning permission, just Building Regs
It's possible that the loft conversion could be permitted development and not need planning permission. It will depend on the sort of conversion proposed - dormer window or not, the type of roof alterations, if any, and the sizes involved.
Building Regs will be required whatever the type of conversion.
You might need to discuss with builder/architect/planner to work out exactly what you are doing.

https://www.planningportal.co.uk/permission/common-projects/loft-conversion/planning-permission

Thanks Seeline,

From my understanding both projects fall under permitted development. Should we go straight to Building control and apply for a Certificate of Lawfulness? My concern would be a Party Wall agreement done twice (paying the surveyor twice) if we treat the projects as being separate?

A certificate of lawfulness is a planning procedure. You provide details of the works and planning tell you whether they agree they are permitted development or not. You don't need to do that process but most people find it better when they come to sell to have proof the work was PD.
Getting building regulations/control approval is a separate process and can be done via the Council or via private inspector. Your builder may have a preference

Party wall agreement is another separate procedure but this is a civil matter between you and your neighbour. You should both have a party wall surveyor

It's been established that what the OP proposes is highly likely to be permitted development (or in the case if the kitchen renovation, not even development under the planning legislation), and therefore doesn't need to submit a planning application.

Building regs will be required. That is a separate process.

In other cases, the risk of applications that cover two unrelated elements us that one element could be unacceptable in planning terms, which means you risk the whole application being refused. You then get a time delay, and probably more expense, in submitting a new application for the remaining elements. It is necessary to weigh up the chances of each element being successful before deciding which route to take.