A Beginners Guide to Building an Extension

This year we've been thinking about extended our house a little. I mean, our house is a good size already, but we've been wanting a little more space in the kitchen, to have a table in there, some room for more cupboards, and a utility, so that we have space for everything we try to do in there. 

If you need more space but you don’t want to move, then building an extension can be the answer, if you have the garden space to be able to do this, that is. But if you're planning on building an extension, there are a few things you need to keep in mind. So here is my beginner's guide on costs, planning permission and more before you start the build.

Before you start your extension, it is good to have an idea of what building an extension can actually entail from end to end. The design through to planning. The costs and building the actual extension. It's a big commitment, and can be a lot of work if you don't do it right. 

What Do You Want?
An extension can be for many reasons, so it's important to make sure the extension you get, is what you actually want, and can be used for what you're planning. As we want to make our kitchen bigger, ours will be at the back of our house, running the whole width of the house. The back of our house is lucky to get the sun for the whole day, so instead of a standard angled roof, we'd opt for fixed flat glass rooflights, so that we can get the amazing sun, the whole day to bring natural light in. 

How Much Does An Extension Cost?
Depending where you are in the UK (London will be more expensive), a straightforward single storey extension can be priced from anything around £1,000–£2,000 per m2. But this cost can vary depending to a number of factors, including size, specification and location. 

And even though it looks like a lot more work, building a two storey extension shouldn't cost much more per m2 because you will only be adding extra walls and floor joists. The main parts, the roof and foundations are required whether your extension is single or two storey.

Designing an Extension
One of the first things you'll need to think about is who is going to design your new extension. Now, you can choose to design it yourself, but remember that the measurements and everything need to be precise otherwise this could cause a delay when it comes to getting permission. You could opt for a build and design company, or you can work with an architect, but you'll need to factor in these costs too. 

Planning Permission
If you're planning a significant extension then it'll be likely that you'll need planning permission and will need to submit an application. Make sure you get this in, and accepted before you start anything.  Engaging with your local authority early on is a good idea to give you an idea of what will and wont be accepted. And take in to account how the extension could effect your neighbours too, as this will have a factor on planning permission being accepted. 


  1. Excellent tips - planning one next year !

  2. Very timely. Have been looking for more space in my tiny kitchen and an extension is much cheaper than moving.

  3. This is really handy thank you. WE have talked about getting an extension for a couple of years. I am totally clueless on where to start so this is a big help!