Planning Permission or Permitted Development


If you are looking to add an extension to your property you will either need to get planning permission or alternatively you may be able to get permitted development and in some instances you can even do both. Each of these options have pro’s and cons and it is important as a homeowner looking to renovate to be aware of what these options are so that you can make an informed choice as to the best route to develop and extend your home.

In order to demonstrate the differences between permitted development and planning permission an example of a detached home with a reasonable garden will be used.

Extending a detached property with a good sized garden under permitted development will allow for the following:

  • Single storey side extension
  • Single storey rear extension up to 8m (provided neighbours don’t object otherwise 4m)
  • Loft conversion of up to 50m3 such as a hip to gable and full width rear dormer
  • Porch no larger than 3msq
  • Double storey rear extension at 3m
  • Large outbuilding in the garden

In comparison extending a detached property with a reasonable garden under planning permission can be slightly more restrictive and will only allow for the following:

  • A side extension no wider than half the width of the house, a 1st floor extension set back 1m from the front elevation extending back to no more than 3m of the original house in very few cases 4m
  • A rear extension of 4m
  • A loft conversion with a dormer set in from the ridge and eave and no wider than half of the width of the roof.
  • In some cases, you could have a porch larger than 3msq

National government have provided homeowners with a lot more freedom than local authority planners which is why permitted development is often a more preferable option. However for those looking to go down the planning permission route it is worth noting that very few applications take less than 8 weeks to be processed and quite often the planner might not even get round to looking at the planning permission proposal until the very last minute, potentially causing havoc to your project timeline and making it very difficult to make any last minute amendments or changes to your plan. Generally permitted development is a much simpler and efficient process which can provide the same if not better results. With permitted development you could end up with the extended home you wanted, in some cases even doubling the floor size without any planning permission just by applying for building control.

Of course only you know what’s best for your home and what you can afford but in most cases, there are more options with permitted development available for a detached house, however any home where permitted development is chosen can be generally more favourable to most homeowners than the delays and issues that can arise from planning permission.

At Byoot for those of our clients that opt for the planning permission route they often describe the most difficult part of the build process was obtaining planning permission for their project. Often, we find the problem to be that the architect is not up to date with what is allowed under planning permission and what could be done under permitted development.

A recent client of ours here at Byoot wanted to maximise the space of a semidetached house, Byoot was able to provide a 2-pronged approach. The first suggestion was to apply for a 6m rear extension under permitted development, thankfully no neighbours objected and the council confirmed this building work could commence. The next step was to apply for a hip to gable loft conversion to increase the loft space with a full width rear dormer.  Again, this permitted development application was granted. Both schemes were implemented and to complete the extension work a 2-storey side and rear extension was applied for via permitted development, which after a few battles was finally approved. Byoot is delighted to have supported our client through this renovation project and build a wonderful spacious home, which allowed them to realise a huge increase in the value of the property.

Had this project been done the other way around by applying for planning permission and then going down the permitted development route the planning officer would more than likely of put a restriction in the approved application to remove further permitted developments rights.

It is always important to plan your renovation & extension project the right way around and work with professionals who can help you make an informed choice. The journey of building your home can be stressful and for most people will be the largest investment they make in their lives. Do it once, do it right!

Byoot provides a full turnkey solution to our clients, from planning, architects, structural engineers, building control and the build, leaving our clients to focus on their day jobs while we do ours. If you are thinking of extending or renovating your home speak to one of the team on 0208 4509185 or send us an email at

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