Calendar delay

...It’s been a really busy time for us. To make sure that we’re able to provide the best possible experience, there is currently a delay of 3-4 weeks to start a project. We are still providing free project advice.

Single Storey Extension 30000 Budget

Single storey extension ideas under £30,000


Written by


Last updated Thursday 14th May 2020

Resi casestudy warrington 05

When it comes to extending your home, you don’t have to break the bank to get amazing results. While some single storey extensions can cost upwards of £100K, others, like the ones we’ll discuss here, are much more affordable.

Not only are these extensions cost effective, they’re fantastic additions for maximising the value of your home, giving you the best chance of recouping this investment (and more) when it comes to selling your home.

Here’s how you can stretch your budget...

Garage conversion

Converting your garage is one of the most budget friendly ways you can add new space to your home. Because the structure of the room is already there, most of your budget will be going to improve the room, rather than construct. This is why many garage conversions can be completed on a budget as small as £5000 - £7000.

Major costs to consider will be the removing of your garage doors, plus adding in more windows in its place. Because you’ll be adding and removing doors / windows, UK law states you must secure building regulations approval. This process will be one of the most costly of your project, with prices being in the range of £1500 - £3000 for the overall service.

Learn more about Building Regulations.

See how much you can borrow

Get an indicative idea of your borrowing potential by answering the simple questions below


Rear / side extension

Thanks to your permitted development rights, creating either a rear or side extension could still be within your £30K budget.

This government created scheme allows UK homeowners to extend their home, without the need for planning permission, providing the extension is both restrained (in keeping with the home’s current aesthetic), and of a certain (small) size.

Because it promotes simple, small scale extensions, permitted development is a great scheme for budget extensions - providing you don’t live in either a conservation area, or flat / maisonette. For between £20 - 30,000, you will likely get…

  • A 20m² rear extension, outside of London.
  • A 15m² side extension, outside of London.
  • A 10-15m² rear extension, inside of London.
  • A 10m² side extension, inside of London.

Extensions inside of London tend to be more expensive, as contractor services are at a premium in this part of the UK. The smaller your extension here, the less time for construction, therefore making these extension within your price range.


If a rear or side extension is just out of your price range, have no fear! Conservatories are a fantastic, budget friendly, alternative.

Prices typically range between £10,000 - £15,000.

What keeps their budget in check is the fact that many can be constructed mainly off site. That means you’re not stuck fronting the bill for contractors to come to your home each day. Not to mention, when it’s ready to be fitted to your home, the build goes from a month long process, to something that can be achieved in two weeks or less.

Conservatories can traditionally be constructed out of three materials…

  • uPVC
  • Timber
  • Aluminium

The cheapest material to use is uPVC, and for this reason, it is a very popular choice for many UK homeowners, as moulding it into the correct shape takes little craftsmanship or time. Timber can also be quite cost effective, but will require real craftsmanship to shape, so more complex structures will push those prices up. On top of this, cheap timber often doesn’t come from a sustainable source, so we encourage you to do your research beforehand.

Finally, the most costly material is aluminium, especially if you’re going for a bespoke frame. However, there are many benefits to aluminum, so the price might prove worth it in the long run.

Learn more about picking a conservatory material.

Modular garden rooms

If you have the excess garden space, and want to create your own private haven, then an annex - or garden room - might be the one for you.

Traditionally speaking, unless all you wanted was a fancy shed, a stylish annex would be cutting it pretty fine with your £30,000 budget. However, with the rise of modular structures, this has all changed.

Whether you want a rustic cabin style abode, or a trendy converted shipping container, prices for a modular builds start from as little as £4000.

Like conservatories, you’re getting something created mainly off-site, so the construction costs are dramatically reduced. There’s also a large range of pre-designed packages, which means you avoid the costs associated with a bespoke design too. Construction on a modular garden room can even be completed within 3-5 days!

Discover your budget options

At Resi, our free consultations allow homeowners to fully explore their options, before they commit to a project. During your call with our team, we’ll discuss everything from design options, planning, timelines, and (you guessed it) budget!

Book your free consultation here.

If you enjoyed this post, you might enjoy our Resi Newsletter, sent weekly via email. Sign up here

See how much you can borrow

Get an indicative idea of your borrowing potential by answering the simple questions below


We are proud to employ architects registered with the Architects Registration Board and were awarded the mark for The Mayor's Good Work Standard for fair pay & conditions, wellbeing, skills, progression, diversity and recruitment.

Phone: +44203 868 9453 | Email:

Resi Design Ltd. trading as 'Resi' | Company No: 10471125