Home renovation

Home Renovation Costs: What to Expect

The job often involves multiple considerations and costs can easily add up, so calculating a realistic home improvement budget is crucial.

Here we look at some of the average costs you might expect to pay if you have your property extended, returned or rewired.

Disclaimer: Prices change all the time, so the information below may no longer be accurate. All prices were accurate at the time of writing and should always be used as a general price guide.

How much does a house extension cost?

Average render cost

Working time

Two bedroom bungalow


4-6 days

Semi-Three bedrooms


6-9 days

Individual of four bedrooms


7-14 days

Home extensions are popular, adding 10-20% to your home’s value. However, they are not cheap with costs varying depending on the following factors:[1]

  • Your location
  • Material quality
  • Type of extension

It can also cost an average architect or architectural technician £750 to draw up plans[1].

Although not a legal requirement, many find it helpful to hire a professional.

Types of Extensions

The three most popular types of extensions are:

  • Single storey extension – a one-story extension of a house
  • Two-story expansion – an extension on two floors
  • Lateral extension – add another room or extra space to the side of an existing building

How much does a single storey extension cost?

If you are expanding a floor of your home, you can expect to pay the following costs[2]:

  • Basic quality: £1,350 to £1,650/m²
  • Good quality: £1,700 to £2,000/m²
  • Superior quality: £1,800 to £2,500/m² or more

Based on the above, a small extension of 20m² can cost between £34,000-40,000, if you use good quality materials.

For an average sized extension of 30m² you should shell out between £51,000 and £60,000.

The work is expected to last approximately 8 to 10 weeks.

How much does a floor extension cost?

If you wish to extend over two floors, the approximate figures are as follows:

  • Basic quality: £1,250 to £1,650/m²
  • Good quality: £1,650 to £2,250/m²
  • Superior quality: £2,250 to £3,000/m² or more

These numbers are similar to those for a one-story extension, as you only add walls and floor joists. The roof and foundation will be needed anyway, but you’re also adding twice the floor space.

If you use the right materials, a 40m² extension over two levels will cost between £66,000 and £90,000.

An average extension of 60m² over two floors is expected to cost between £99,000 and £135,000.

Construction should take approximately 12-16 weeks.

How much does a side extension cost?

Another option is a side extension, which usually involves extending the kitchen or living room, and you should be paying around £1,250-2,500 per m².[1]

Prices for side extensions vary depending on the quality of the materials and the degree of reconfiguration required. If you plan to have a kitchen in the extension, for example, it will require plumbing. If you have a gas stove, you may also need to have the pipes modified.

For a side extension you should budget over £75,000 – and at the high end they can cost up to £300,000.

The construction of this type of extension should take approximately 10 to 12 weeks.

What is house plaster?

House plaster consists of covering an exterior wall with cement, lime, acrylic or another mixture.

It is a relatively inexpensive way to protect masonry, gives the building an even finish, and can be done in any color.

How much does it cost to render a house?

There are several types of rendering, which vary in quality and cost. In addition to materials and labor, there will be additional costs such as rental of dumpsters and scaffolding if you need to render more than one floor.

According to the Traders Research website Checkatradeyou should budget £31.50 to £63 per m² for a plastered wall including paint[3].

But how does this translate into properties of different sizes?

These are approximate costs using cement plaster and assuming the bungalow will not require scaffolding. Your craftsman will give you a more precise quote based on what you need[4].

If you need scaffolding it should cost between £400-600 per week.

For materials, cement tends to be the cheapest option. Here is the range of options, with costs and considerations[5]:

Render Types

  • Cement (from £10/m²): the most common and standard choice of coating in the industry.
  • Lime (from £20/m²): Breathable and moisture resistant, it is also suitable for older properties.

Types of finish

  • Masonry painting (from €20 to €30/m²): This protects certain types of coatings. In addition to color, you need to consider texture and sealing qualities.
  • Pebbledash / plaster (from £30/m²): A waterproof finish that helps insulate the property.

Pre-colored/finished plaster

  • Acrylic (from £30/m²): A topcoat for new and existing plaster, which can reduce the amount of cleaning needed in the future.
  • Polymer (from £30/m²): a type of plastic that reduces the risk of cracking. It can also be colored which means you won’t need to paint afterwards.
  • Monolayer (from £35/m²): Although more expensive, this only requires one coat which means lower labor costs.

How much does it cost to rewire a house?

Old and faulty wiring in a property can be dangerous, so it’s important that your wiring is in good condition. If you are moving into an older property, especially one that is 25+ years old, having your cables inspected should be a priority.

The job is to remove old wires and fittings, install new ones and upgrade the consumer unit. If you have new equipment, this may also involve cutting walls and ceilings.

After installation, the electrician will perform tests to ensure that all wiring is working properly. This is known as an Electrical Condition Report (EICR), and you will receive an EICR certificate once it is cleared.

These are the prices you expect to pay for rewiring[6]:

Average rewiring cost

Cost Duration

Two bedroom apartment


4-6 days

Two bedroom house


3-4 days

Three bedroom house


5-7 days

Four bedroom house


7-10 days

Five bedroom house


10-14 days

Jthese are average costs. They can vary depending on the location, size and age of your property.

Other factors can also cause a job to take longer. For example, if the property is occupied, it will take longer to complete the work than if the property is empty.

Also, if you have a lot of new fittings to install, or multiple custom fittings, these will take longer to install than having just a few standard fittings.

If you are looking to sell your home, here are some home improvement ideas to catch the buyer’s attention.

Home insurance for home renovations

If you are undertaking major home improvement projects, you should let your home insurance provider know. Otherwise, you risk invalidation of your home insurance policy if something goes wrong during construction.

You should also check that you still have the correct level of Home Insurance when the job is done. Extensions and other structural changes are likely to increase the value of your property, and you don’t want to be underinsured.

Need financial help?

In 2021, building an extension was the top reason people took out an Admiral Money loan for home improvements.

You can potentially borrow £1,000 to £30,000* between 12 and 60 months to start your project or finance the entire balance.

* The rate you are offered depends on your personal situation and all loans are subject to status. The interest rate offered varies based on our assessment of your financial situation and the loan amount you have chosen.