House-Extension-Cost-2020-Stairs

How much will my extension cost in 2022?

When it comes to home-renovating the most common question is this one: What’s the cost of building an extension?

This question becomes especially crucial for those of us making the decision to move house and stretch to get that fixer-upper, or those wanting to turn their current house into their ‘forever’ home.

It’s an especially daunting time for home-renovating, when faced with both wanting to to future-proof our living situations and industry-wide construction costs rising (both labour and materials). We need not only a place our families can grow, but also space where we can work which adds an urgency to extending, refurbishing and improving our homes.

House-Extension-Cost-2020-Internal-Renovation

So, let’s get right to it. How much will it cost you to extend your home? And how do you work out the REAL cost?

There are FOUR different ways you can tackle these questions:

  1. Find a square metre cost
  2. Use a cost calculator
  3. Get an early cost estimate from a builder
  4. 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!

*SPOILER ALERT* Making a budget based on real project percentages is the best way! Skip to Strategy 4 if you want to save time.

Strategy 1: Square metre costs

As a rough estimate of construction costs, you can expect to pay:

  • Basic quality: £1,350 to £1,650/m²
  • Good quality: £1,700 to £2,000/m²
  • Excellent quality: £1,800 to £2,500/m² [1]
  • High-end bespoke design: £2,500-3,000/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!

Check out our top three favourite cost calculators below:

Urbanist-Architecture-Logo

This simple cost tool by Urbanist Architecture 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.

This costing tool also gives a quick ballpark calculation. It uses your address to tailor prices to your region, and takes into account the number of storeys and quality of your build.

It gives you an overall estimate per square metre that includes all construction costs, clients’ selected items and VAT. It does not include consultants’ fees.

We advise to use this calculator on its highest settings to give a more representative price of a design-led project in London.

2PM-Architects-Logo

London-based 2PM Architects have developed another helpful guide.

It includes costs per square metre for different levels of specification (basic, medium and high) and is based on 2020 prices.

It also has an online cost calculator that, based on your answers, immediately gives you an idea of prices and simultaneously displays your project per square metre rate.

House-Extension-Cost-2020-External-Brick-Extension

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.

We have created a FREE Renovation Budget Breakdown Guide that unpacks all the figures of a project – from building costs and professional fees to those extra expenses that no-one tells you about.

This will put your construction budget in the context of the whole project’s costs and make sure you’re considering all those added extras from the outset.

House-Extension-Cost-2020-Bedroom-Renovation

References

Our HomeNotes Journal is here to bring you clear and up-to-date information for homeowners renovating their homes. For more in-depth help we provide online courses to help you get started the right way!

Open-House-Festival-Front-Cover

Open House Festival: 8th – 21st of September

For those who have decided THIS is the year that they’re going to bite the bullet and renovate, Open House London is a chance to go and see some projects up close and personal. Here’s our list of recommended projects to go visit.

Read More →

Why do we still not have a national retrofit strategy?

We talk to Paul Testa of HEM Architecture about why we need a national retrofit strategy and why it needs to happen now.

Read More →
Front

How to prepare your house for builders: 10 things you must do

When getting ready to receive contractors into your home it’s important to prepare your property. Get started with these 10 must do tasks!

Read More →
House-Buying-Checklist-Front

Our 10 top tips to buying a house

Buying a house is potentially the biggest financial commitment you will ever make, so take the time to prep with our tips!

Read More →
Dont-Move-Improve-Front

Don’t move, Improve! 2022 Shortlist

Check out the 15 incredible London renovation projects shortlisted for this year’s Don’t Move, Improve! Awards and get inspired!

Read More →

Viewing a property: The ultimate checklist

You’ve done your research! But when you’re in the actual property, remember to consider the following things…

Read More →

Where NOT to scrimp on your renovation

Sometimes it’s tempting to cut corners and save a few pounds but it’s likely you’ll regret it in the long term. We share our top tips of where it doesn’t pay to scrimp in your dream home.

Read More →
Trade-Shows-PoulsomMiddlehurst_Amhurst_External-Door

How to make the most of a Trade Show

Returning to thoughts of renovating your home? Then jumpstart your project by attending a trade show. But first make sure you read our top tips on how to make the most of your visit!

Read More →

Top tips for renovating from industry experts

We asked a range of architects and experts working in the residential sector to give us their top tip for homeowners who want to renovate.

Read More →

Worried about increasing construction prices?

Everyone is concerned about increasing construction costs. We talk to BuildPartner about what measures home renovators can take to reduce risks for their projects.

Read More →

Your handy guide to assessing builders

Linden from Weaver shares his a handy guide to assessing builders. So before a spade is in the ground, it’s worth taking a moment to prepare.

Read More →
Little-Bishop-Front

Product spotlight: Little Bishop Hook

A neat solution for pendant lighting; we take a look at the clean design and appealing simplicity of the Little Bishop Pendant Hook

Read More →

The ‘Iron Triangle’ you should embrace

It may sound daunting, but knowing about the ‘Iron Triangle’ in advance can help you plan your project and set realistic expectations.

Read More →

Making the most of your outdoor space

If you’re living in London, then chances are you’re severely lacking in one department: outdoor space. But even if you only have a small patch to play with, this space can do so much for you with a bit of care and forward planning.

Read More →
Ultimate-Guide-To-Extractor-Fans-Front-Cover

Your ultimate guide to extractor fans

Our complete guide answers all your extractor fan questions (even those you didn’t know you had!)

Read More →
EJ-Ryder-Interview-Front

EJ Ryder and the world of joinery

Edwin J Ryder and his team specialise in bold, creative design and impeccable workmanship in their joinery and interior finishes. We spoke with Edwin to find out how they work with clients on their property renovations.

Read More →
The-Modern-House-Front

Why well designed homes cost more

Good design isn’t just a luxury for those with the biggest budgets; it’s a sound financial decision for everyone. We take a look at The Modern House and their approach.

Read More →
Millennials-Managing-Money-Front

True or false: millennials are bad at managing money?

Research shows that millennials are the group most likely to overspend on their home improvements. Poor money management, or is there another explanation?

Read More →
Trade-Shows-PoulsomMiddlehurst_Amhurst_External-Door

Being the boss (yes that’s you!)

As a homeowner undertaking a renovation project, you become ‘The Client’. It can sound pretty clinical, but what does that actually mean?

Read More →
TurnerArchitects_SthCroxtedRd_Cover

Your ultimate guide to cabinet handles

Handles are that small but important detail that can really lift a piece of furniture or a space. But look no further for your ultimate guide!

Read More →

Coming soon . . .

Our membership is launching at the start of June.  Sign up to get notified when it goes live! 

Sign up for

HomeNotes news

Get monthly renovation articles, advice, news and offers to your inbox!