How much does rear extension costs?

How much rear extension cost ?

At start building an extension seems difficult; you have do not know where to start and who to talk to. But when you have an idea about the cost of your project then the things look somehow organized.

ARCHITECTURE is here to help you everything to ensure your project runs swiftly as possible.

Size of the extension

The price of your project will depend upon the size of e extension you need.  Generally, it can cost between £1200 and £1500 per m2. This could rise in London and the south east to £1500 and £2000 per m2.

Suppose if you are interested to build a 5m X 5m extension this would cost around £30,000. However, this estimate could rise extensively if you are going to build in London or the south east.

To estimate a two-storey extension, simply multiply a single storey estimate by two. If your single-story cost £30,000 then the two-storey cost would be £60,000.

Other costs

There are many other costs outside this sphere which MR. ARCHITECT will bring down for you….

  1. Architect fees


The most important aspect of any extension is to find a good architect. The architect can

make or break any project. MR. ARCHITECT provides the best experts in the field of architecture. Not every architect is economical unless you use MR. ARCHITECT.


  1. Admin costs


You need approval from the council even you have obtained planning permission or working under permitted development rights. This requires a fee. These costs would be increased if your application gets rejected. This increase will happen when the dispute comes up with the party-wall agreement.


  1. Building regulations


Building regulations are a set of principles that would be necessary to fulfill like fire safety, energy efficiency, household fuel conservation, and many other important aspects like these.

For their approval, a prescribed fee is required. Most of the people don’t think about this hidden cost


  1. Flooring


Flooring is also an important step in your extension.

The cost of the floor completely depends on you.

You should think about which type of floor is best for your extension.

When you choose a hardwood floor rather than a laminate wood floor the price would be increased automatically. However, this will make increase its resale value of your house.


  1. Glazing


It is critical to choose a glazing style that would be right for your house. Whatever you make changes to your house it will affect your day to day life.

Double glazing is an expensive style but it looks amazing.

The Cost of double glazing is around £2,000.

However, the Secondary glazing is a cheaper alternative.

  1. ARCHITECT suggests you check the U-value before purchasing your window.


  1. Removing a wall


The removal of any wall may be an economic concern. This wall can be either internal or external.



Removal of a wall cost from £300 to £1200 per wall.

The cost depends upon whether your wall is load-bearing or not.

Price variations

In the above all mentioned prices, utilities or fittings are not included. These things are personal to the budget of an individual.


If you’re looking to go forward with a rear extension project, why not speak to an expert? Book in a free consultation call with one of our experts.

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