Can you change an extension?

It’s human nature to change your mind regularly. Especially when designing your dream home, you might see a better route to your vision, or just different one altogether. Us creative types cannot be confined to one single plan, we need options!

So, say you’ve moved into a new property and the home has already had some work done to it by its previous owners, but you can see so much more potential. Or you’re in your existing home that you’ve done a bit of work on already, but all this lockdown malarky has made you feel a bit cabin fever-y and has prompted you towards the decision of needing even more space, a home office, playroom or a way to open up your kitchen, so you’ve got room for all the banana bread and sourdough bread you’ve been making.

This begs the question, can you extend or change a pre-existing extension?

Short answer, yes.

Needless to say, there will be different answers for different situations and it will heavily depend on a few varying factors too. There are three main considerations that I’m going to highlight and hopefully explain to make it a bit easier to see where you stand.
  • A non-material amendment
  • A new application
  • Permitted development

Non-material amendments

So, the government understands that the most beneficial approach to planning permission is if there is an element of flexibility to the procedure. For a small fee, minor modifications can be made to already approved plans, which gives you a bit of wiggle room. An example of a non-material amendment could be:
  • A reduction in the size, volume or height of the extension. Which is quite self-explanatory, if you’re going smaller, you should be able to do this without needing new plans.
  • An amendment to any of the windows, doors or openings providing it will not have any impact on the neighbouring properties. If you change the style of window or door for example, like you go from frosted glass to completely clear, transparent glass this might perturb some of your neighbours, so it may then require a consultation with them, that means this type of work is disqualified from non-material amendment.
  • Alterations to the design or siting of the building. This would be more related to the actual aesthetic of the extension, if you’ve decided you don’t like how it looks but have no intention of changing the size or height, this should hopefully land under a non-material amendment.

A new application

Of course, there may be times when you just scrap your original plans, maybe you’ve decided you want to go significantly bigger and add an indoor bowling alley (I wish!), what do you do then? It may be time to consider submitting an entirely new application. The main rule of thumb is that if your changes are much more complex than the original plan or they require a new consultation with your neighbours, then a new planning application needs to be submitted. These changes could include but are not limited to:
  • An increase in volume, size or height of the extension. As soon as I hear the word ‘increase’ when it comes to questioning if you need to submit a new application, I wouldn’t even need to google it before I know that the answer will be yes!
  • Additional or repositioned windows that impact neighbouring properties. This revision is affecting your neighbours, so you’ll need to consult them which automatically results in your needing a fresh planning application.

Permitted development

This is probably my favourite topic in this blog because it almost feels like a loophole that I only just learned. Basically, I just didn’t know this was an option until a started working in construction…
Permitted development allows certain alterations to be made to your home without needing full planning permission. Planning permission can actually take up a decent chunk of time to be pushed through, sometimes up to three months. Some of the projects that could fit under the permitted development bracket would be:
  • Any interior remodelling
  • Roof lighting
  • Conservatories
This actually brings me nicely on to me being able to brag about O&U’s little sis, Habattach. With Hab, you won’t need to endure the three month process. We’ve ensured that in the majority of cases, our product will fall in line with permitted development with the exception of listed buildings.

Habattach Pre-Fab Alternative

Habattach is a low cost and effective extension solution for anyone who is looking for a low cost option with high quality and aesthetically pleasing finish.
If you’re interested in exploring how Hab can fit into your plans, just drop us an email at

O&U Design and Build Package

Olive & Umber provides a Design and Build package for those of you wanting extensive work done to your property. We can facilitate the design of your project all the way through to handing the keys back when the work is done! If this sounds like something you need then drop us an email to and we would be more than happy to answer any questions.
Side Rear Extension - Portfolio