Are you wondering how much a double storey extension will cost you?
In this article, we’ll review all potential costs and discuss the various kinds of extensions as well as the advantages of each.
How Much Does It Cost to Build a Double Storey Extension?
As your family expands, your house may get too small. Instead of moving perhaps you’d prefer to remain where you are and instead build a two-storey extension to expand the size of your house. What is the cost of an extension that is double storey cost?

The total price of a double-storey extension will differ based upon the dimensions, degree of difficulty and the area you are located in. The cost for an extension of a double storey is between £40,000 and £100,000.
On an average, you will need to pay between £1000- £1750 per square metre. There are any additional charges for installation of fixtures and fittings, such as bathroom fixtures and kitchen fixtures. The additional cost will depend on the things you intend to accomplish with the additional space.
Doubles Storey Extension Prices
Below is a breakdown of prices you could expect to pay for a double storey extension. Remember it is a good idea to consider that the smallest extension will be approximately 30m2, the medium extension will be around 60m2, while a large extension is about 100m2.
Job Description | Average Cost |
Small, basic double storey extension | £35,000- £45,00 |
Small average double storey extension | £40,000- £50,000 |
Double storey extension of a small size. | £50,000- £60,000 |
Extension of a basic double storey | £60,000- £70,000 |
Medium average double storey extension | £65,000- £75,000 |
Medium deluxe double storey extension | £70,000- £80,000 |
The extension is a basic, double storey addition. | £85,000- £95,000 |
Large average double storey extension | £90,000- £100,000 |
Large deluxe double storey extension | £100,000+ |
What is the supply cost for Double-Storey Extensions?
There are a variety of costs of supplies that are associated when you have a double-storey extension.

Here is a list of the possible double storey extensions costs you might need to consider:
Different types of supply | Average Cost |
Foundations | £3000- £10,000 |
External Brickwork | £2000- £5000 |
Roof Materials | £1000- £3000 |
Bifold/French Doors | £1500- £2500 |
Windows | £1500- £3500 |
Rendering Materials | £30- £ £50 per m2 |
Internal Decorating Materials | £400- £1500 |
Radiators | £400- £3000 |
Underfloor Heating Materials | £1000- £4000 |
Kitchen Units | £3000- £10,000 |
Kitchen Worktops | £20- £500 per m2 |
Washing Machine | £200- £500 |
Oven | £300- £800 |
Hob | £100- £400 |
Cooker Hood | £200 £500 |
Dishwasher | £300- £600 |
Fridge Freezer | £200 £800 |
Flooring | £10- £100 per m2 |
Wall Decor (Tiles/Wallpaper/Paint) | £20- £50 per m2 |
Windows | £200- £600 per |
Exterior Door | £400- £900 |
Internal Doors | £50 £300 per door |
Bathroom Suite | £2000- £10,000 |
What are the additional costs of building a Double Storey Extension?
There are many additional expenses that could arise when making a double storey extension.

Here is an outline of the major extra costs that could arise from this type of job:
Hire of scaffolding
If you’re planning to construct a double storey extension, you’ll need to rent scaffolding to allow the construction workers to gain access to all areas of your site of work. Sometimes, the construction company might provide scaffolding to you. If you don’t have them, you’ll need to find out what scaffolding costs to hire.
The cost for building a scaffolding tower is about £200 to £300. The price will vary based on the length of time you’ll have to lease the scaffolding.
New Roof Installation
If you have a double storey extension that has been built it is necessary to put a roof on the top of your new extension. The cost of installing the roof on your brand new extension ranges from £1000 to £2000 depending on what size the roof.
New Bathroom Installation
If you are getting a new double storey addition and you decide to build a bathroom into the space. If that’s the situation, you could anticipate spending between £3000- £6000 to get a new bathroom built in your house.
New Kitchen Installation
Additionally, you might consider adding a kitchen to the extra space of your double storey extension. The cost of installing kitchens in your house is between £6000 and £9000 but this may vary in different sizes and styles.
Tradesmen’s Costs for an Extension of Double Storey
The costs for labour to build an extension that is double-storey depends on the extent of your extension as well as level of difficulty of the task, as well as the area of your home.

On an average, you should expect to pay between £150- £250 daily for every contractor who is on the task. The majority of the time contractors will collaborate in teams comprising 3-4 persons.
It is important to remember that you’ll also need to hire additional contractors for this kind of work. Here’s an overview of the additional costs for labour that can be associated with the installation of a double-storey extension:
Tradesperson | The Average Cost per Day |
Electrician | £125- £300 |
Plumber | £150- £200 |
Roofer | £150- £225 |
Kitchen fitter | £125- £175 |
Joiner/Carpenter | £125- £180 |
Plasterer | £100- £250 |
Painter/Decorator | £150- £200 |
Floor Fitter | £150- £200 |
Tiler | £150 £200 |
How long does it take to construct a Double-Storey Extension?
The construction time for the double-storey extension will be contingent on a variety of factors, including the effectiveness of the builders and the weather conditions that will be encountered during construction, and the complexity of the task.

Below is a table of the time spans for different double storey extension work:
- Very small (30m2) two storey addition – 8-10 weeks
- Medium (60m2) double storey extension 10-12 weeks
- The building is large (30m2) Double storey extensions installation that will last 12-14 weeks
Also, you should consider additional time for more complicated extensions and more extensive additions. If you have to obtain permission to plan, have work done through an architect, or get the approval of a party wall You will need to include some additional time before building can begin.
Different types of double storey extensions
There are many types of extensions for double-storeys that you are able to select from. Here is a listing of the various types of double-storey extension available for you to think about:
Double Storey Front Extension
A front extension with a double storey is likely to be the least used extension style. It is due to the fact that it has the greatest impact on the overall appearance of the house. If you are building an extension on this property there are more stringent rules for building that must be followed.
Double Storey Side Return Extension
This kind of extension is constructed on the opposite other side, and does not impact the garden. This kind of extension is suitable for detached semi-detached or totally detached homes with sufficient space on the sides for the extension.
Double Storey Rear Extension at the Rear
The extension is a type that extends from the back of the house and generally extends out into the garden. This kind of extension is ideal for detached and semi-detached properties. It can, however, be used on terraced homes with sufficient space in the rear.
Double Storey Wrap Around Extension
This kind of extension is a combination of side and rear extensions. If you’re looking to add more space in your home then a wraparound extension could be the ideal choice. This kind of extension could provide a large amount of living space and is suitable for detached or semi-detached homes.
The benefits of the Double Storey Extension
There are numerous advantages for installing a double storey extension in your home.

Here is a list of the benefits of this kind of work:
Extra Space
The addition of a second storey to your house is a fantastic method of increasing the size of your home without the need to relocate. In this regard, you can also save money because you won’t have to worry about the costs of solicitor’s fees, estate agent charges or stamp duty.
Additional Rooms
If you decide to add an extension that is double storey this allows you to create additional rooms to your property. You can select the dimensions and style of the room that meets your requirements. A few examples of rooms that can be added include guest bedrooms or a wet space as well as an office space and a brand new kitchen or bathroom.

Additionally, if you do not need more rooms, your double storey extension could serve to create existing spaces bigger. If you’re thinking of the double storey extension there are a lot of possibilities to select from, and you’ll have the ability to customize your home to suit the way you like it.
Pro-Rata Costs
The addition of a single storey will give you more space however, it is less per square metre to add an additional layer.
Because you must build a foundation and roof, regardless of whether you’re making a one-storey or a two-storey addition, the additional storey will require internal walls, exterior finishing, and the finish for the interior.