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Extension Costs: 2024 Cost Broken Down

Rear house extension with flat roof and grey bi fold doors

We all know that extensions make a fantastic addition to any home, adding a significant amount of space and square footage, which not only makes living there more enjoyable but also adds value if you were to ever sell and move on. Adding an extension is a more cost-effective way of accessing more space as opposed to moving house, especially when you consider all of the legal fees, stamp duty, moving costs and, let’s face it, the stress that comes with moving home. So, if you’re happy with where you live and don’t want the stress of moving but want more space, an extension is a great solution. Unfortunately, it does come at a cost, which we’re here to discuss today.

How Much Does An Extension Cost?

The cost of an extension, according to Checkatrade, can vary from £40,000 for a basic 20-metre squared extension excluding VAT, increasing to closer to £60,000 for a 30-metre squared extension, then £75,000 to £100,000 for large extensions and premium extensions.

This is just a ballpark, as the cost can be less or more depending on the quality of materials you choose, whether a kitchen is being fitted with the extension, how long it takes, how complicated the current structure of your home is, the changing costs of plant hire, and so on.

There are also so many different types of home extensions, from single-story to multi-story, semi-detached to kitchen and loft conversions through to garage conversions. However, overall, realistically, you will be looking at between £40,000 and £60,000 for an average extension on your home.


Things That Influence How Much Your Extension Might Cost

  • How big the extension is – this may be a given, but the larger your extension is, the longer it takes, the more materials that are needed, the more labour that is required, and so on.
  • Where your home is – typically if you live in and around London, near the South East or any of those surrounding areas, your extension will cost more. The cost of living is higher down south so that naturally filters into the world of construction too.
  • The quality of finish – how complex the extension will be, what type of materials are used, whether you’re having features like underfloor heating and how skilled your contractors are can all significantly impact the cost of an extension.
  • If you need an architect – for any remotely complex extensions, working with an architect is highly advised, as it helps to simplify the process and ensure that you don’t run into avoidable issues later down the line. It costs a lot more to resolve something that was done wrong than to pay a bit more by working with an architect to get things right the first time!
  • What’s currently in the space – if there is work that needs to be done to prepare the space for an extension, such as removing trees, installing patio tiles and so on, this is an extra expense you’ll need to consider.

Windows and doors – if you’re having windows and doors fitted as part of the extension, this will cost more, especially if you’re having something like a sliding door that will also require structural attention.


How To Reduce Costs If You’re Having It Built

Now that we know how much an extension is realistically going to cost, we’re going to talk about how to reduce costs if you’re having an extension built into your home!

Carefully Consider The Size

The first thing you should do is carefully consider the size of your extension. As we’ve discussed, adding an extra 10 metres squared can potentially add £20,000 to the cost of your extension, so thinking things through carefully is key. However, this being said, you do need to find a balance, because if you end up going too small with your extension and not getting the functionality that you need out of it, then it will end up being a big waste of time and money. So, try not to go over the top with your extension, but also make sure that it will serve the purpose you want it to, which careful planning will really help with.

Don’t Take Your First Quote

One of the best pieces of advice we can give you is to not take your first quote. Of course, you absolutely shouldn’t go for the cheapest option just for that reason, as there is a reason some people charge more for their work and you want to get this right. However, getting a few different quotes for the work and looking at plenty of examples of what they’ve done and their reviews is so important to make sure you’re not overpaying for the service.

Work With Someone Well Recommended

The ideal scenario when you’re looking for a contractor is to work with someone well-recommended. You want to know that the quality of work is very good and that people who’ve used them haven’t experienced any issues later down the line, for example, leaks when bad weather comes around or foundation issues. So, if you can get a great personal recommendation because the last thing you want is to budget for a project, have it completed and then need to pay to get anything resolved if you don’t hear anything from the builder again, So, working with someone well recommended might not cut costs in the short term, but long term, it’ll give you peace of mind that you’ll be getting the best results

Minimise Structural Changes

Last but not least, a surefire way to cut costs is to minimise structural changes. When you have anything structural done, the cost of your extension increases quite significantly, so reducing this where you can is key.

Again, as we mentioned earlier, you need to find a balance between saving money and getting the results you want, and sometimes structural work will be needed to achieve the bare minimum of what you’re looking for. This is why working with an architect is advised, as they can help you identify where structural work is needed and where it’s not, minimising costs while still helping you get the results you want.

The upfront cost of an architect can be between 5% and 10% of the project cost, however, it can make a huge difference to the overall cost and result.

Front of house extension being built.

Final Thoughts

Extensions are a substantial cost, however, in comparison to moving, they’re far more cost-effective. While there are ways to reduce the cost of your extension, our best piece of advice is to very carefully consider this process and not rush it, as you want to ensure that you are going to get the results you need from the extension, even if it does mean spending slightly more, as it will be worth it in the long run. Take your time to get this right and you’ll thank yourself for it in the future!