So, let’s get right to it. How much will it cost you to extend your home in 2025? And how do you work out the REAL cost?
There are FOUR different ways you can tackle these questions:
- Find a square metre cost
- Use a cost calculator
- Get an early cost estimate from a builder
- Create a budget breakdown
In this article, we’ll go through each strategy, highlighting its pros and cons, so that you can plan for the future with confidence!
Strategy 1: Square metre costs
As a rough estimate of construction costs, you can expect to pay:
- Basic quality: £1,500 to £1,750/m²
- Good quality: £1,700 to £2,100/m²
- Excellent quality: £1,800 to £2,500/m² [1]
- High-end bespoke design: £2,800-3,000/m² or more. [2]
And as a rule of thumb, an excellent finish will cost you 40% more than a standard finish. [3]
BUT (and it’s a big but, I’m afraid) there are a lot of caveats with these prices!
1. Location – where you are based in the UK will change the square metre rate. For example, if you are in London, be prepared to pay more.
2. Scope – what you want to build will obviously make a difference to the square metre rate. If you’re going for a two-storey extension with marble worktops and a polished concrete floor … that’s going to cost more than a “box on the back”.
As an aside, some experts might say that you get economies of scale (cost advantages) if you do a larger extension. In fact, some may say “twice the height, half the price”, but this is sadly a little bit of a red herring. Work out your overall floor space and ensure your budget matches. [4]
3. Team – the professionals that you get on board to help you will potentially impact the overall costs of the project.
4. Involvement – how involved you want to be in the process will affect the costs of the project too. For example, if you are a pro DIYer and choose to source and install the kitchen yourself as opposed to outsourcing this to a kitchen company, that decision will impact the cost.
Strategy 2: Cost Calculators
Cost calculators are tools you can find online to help set your target budget. They can be beneficial, especially to work out a rough construction cost. However, you need to be really careful when using these tools. They are only as reliable as the information you put into them!
Our top cost calculator is this simple cost tool by Urbanist Architecture which is good for a quick ballpark calculation. It’s based on projects in either central or outer London.
It gives you an overall estimate per square metre for either a refurbishment or new-build extension.
The calculation includes all construction costs, clients’ selected items and basic consultants’ fees and allows you to select the level of finish for your project.
Strategy 3: Early price estimate
This can be a really great way to get an idea of costs in the early stages of thinking and strategising. But remember that it’s exactly that – an idea of costs. One of the drawbacks of getting an early price from a builder is that that becomes the figure stuck in your mind – even if you decide to do more than you initially intended!
But if you want to go down that route, here are a few tips to bear in mind:
1. Ask what the price includes
Often the builder will tell you a price that is only the construction cost. But remember you also have VAT, contingency and professional fees to consider! Plus, it’s unlikely they’ll include client supply items like your kitchen or sanitary ware.
2. Ask what work the builder has on his plate
Prices will change dramatically depending on the market. If your builder needs the work, then he’ll go lower to secure the project. If he’s flat out and doesn’t need the work, then it will be higher!
3. Do your research
Make sure you’ve done your homework on the contractor you get round for a quote. Ideally, it’d be a builder who is working on projects similar to what you have in mind. So, if you’re looking to achieve a ‘Grand Designs’ forever home, then you need to find a builder who suits those plans
Strategy 4: Budget Cost Breakdown
It may come as no surprise that we advocate making a detailed budget. It’s not the easiest, quickest or sexiest-sounding solution! But if you want a more accurate breakdown of the costs of your extension, making a detailed budget is the way forward.
It’s safe to say that most people renovating their homes won’t be able to afford everything they want to include. Renovating your home is a balancing act between what you wish to create and what you can afford.
When the budget is tight, this balancing act becomes even more critical.
So before you do anything else, it’s essential to get to grips with the different aspects of a construction budget and how these elements work together. This will help you make some fundamental decisions before the project has begun.
If you need any help with this, we’ve got you covered! Our HomeNotes App was designed to help homeowners get a handle on their budget, based on real-world costs. Start your free trial below!
[1] https://www.homebuilding.co.uk/advice/how-much-does-an-extension-cost
[2] London Architects Group (http://londonarchitectsgroup.org/)
[3] https://www.homebuilding.co.uk/advice/how-much-does-an-extension-cost
[4] https://www.mybuilder.com/pricing-guides/house-extension-costs
