How much does a House Extension Cost?

A new home extension can be a great way to add space to your property – but how much will a house extension cost?

Installing a new house extension from any part of your home is the perfect way to make extra room and give everyone a bit of added space – not to mention possibly adding value to your property! Plus a home extension can make life just that little bit easier – if you want more cooking space, perhaps, or if you enjoy having friends and relatives over and need the extra room to let them stay overnight. It all sounds perfect – but how much is this sort of home improvement project going to cost?

House Extension Cost: Prices Summary

So how much do house extensions cost? Well, most builders and contractors in the UK agree that there is no single way of finding a perfect estimate for a new home extension project, as many things are likely to change during the construction and design process depending on what you are able to do with the property you have. Nevertheless, we sourced the following figures to help you get a rough idea of how much a house extension will cost the average home-owner in the UK.

Type of House Extension Service Cost (£)
A single storey, ground floor extension 1000 per square metre
A through-room home extension 2500 – 3800 per square metre
A double-storey house extension 60,000 to 75,000
Planning Fee 172
Building Regulation Fee 200 + VAT

As you can see from our research, you will need to take into account hidden costs such as “planning fees” and “building regulations fees” that will contribute to the final house extension price.

Budgeting for a new House Extension

Even though you can’t pin-point an exact figure for your home extension project, there are things that can affect the final house extension cost that you can take into account when drawing up a preliminary budget, including…

  • The size of your projected extension and the shape and measurements of your floor plan.
  • Whether or not you are opting for a single or double storey home extension.
  • The installation of plumbing and electrics, from a shower cubicle, toilet, sink basin and bathtub to room for dishwashers, washing machines and new kitchen sink units, as well as light fittings and electrical sockets – in fact, any pipe work and re-wiring will add a significant sum to house extension prices.
  • The height of the ceiling in your planned extension.
  • Whether or not you opt for a through-room extension that blends neatly with your existing interior.
  • Whether or not you need to integrate a new chimney and flue installation into the extension.
  • The potential removal of existing walls and/or party walls.

Hiring a team of professionals to build your Home Extension

One of the first things you will need to do before getting started with your home extension is to find out whether or not you will require planning permission from your local authority. According to the Party Wall Act 1996 any new builds that might affect an adjacent property will usually require planning permission – whether it is the outside view from the neighbouring home or the structural integrity of a party wall itself. Although some single storey extensions might be classed as “permitted developments” that don’t technically require planning permission, it is always a good idea to take your plans to the local council and double-check first.

If you want a cheap house extension built properly and safely, you might also want to look into hiring a team of dedicated professionals to do the majority of the planning, removal of walls and building work for you as well. This team will usually consist of a project manager and experienced group of labourers, but might also include a quantity surveyor, architect and structural engineer. This might seem a bit over-complicated, but it ensures a wide range of professional support in the construction of your brand new home extension.