The prices are based upon user input and personal experience and are guides to the rough pricing rather than exact figures that you will pay.

If you have any of your own data to feedback to us then please do so below.

How much is my house extension, home renovation going to cost me?

This is the question most frequently asked by people looking at getting a house extension. To be honest at the start of a project it is impossible to quote building costs without working drawings and a list of materials, fittings and fixtures.

Building costs for house extensions or home renovations can vary considerably depending on a number of criteria:

• Choice of building materials, fittings and fixtures – bathroom and kitchen tap fittings, tiles, window frames, heating & cooling, lighting
• The extent of client involvement – does the client choose to perform any of the building works such as painting
• Commencement and duration of the building works – does the project extend over the Christmas holiday break or during seasonal busy periods – this will add to any interest cost and/or rental costs if you need to move out
• Seasonal building market conditions – the number of rain affected days – this will add to any interest cost and/or rental costs if you need to move out
• Town planning delays – this can result in additional costs and potentially add months to your building project
• Size and competence of the selected building firm or builder – the bigger the business the more overheads and, by necessity, will pass this cost on to you
• Each builder will factor in a different profit margin
• Soft landscaping
• Varying professional fees – architect, draftsperson, town planner, structural engineer, soil report, building surveyor, etc
• Abnormal ground conditions requiring additional site costs – a sloping block and/or the need to dig deeper to reach solid ground and so concrete pours will vary
• And finally, there is the point of location, location, location. For example, a House Extension in London may cost more than a House Extension in Manchester, only because the cost of building is greater in London than in the North West.

However, considering that planning permission and drawings from start to finish wil usually wind up at about £1,500 give or take some, the prices below will give you the averag costs for a house extension. The rest is up to you and your preferences in the refurbishment of the interior.

Loft Conversion Prices

As mentioned above, the bottom line when planning any building project is ‘How much will it cost’. Loft conversion prices vary from region to region within the UK and, of course, no two conversions are likely to be the same.

But, we can use some ballpark figures and rule-of-thumb.

The first, and arguably the most important, is that by building a loft conversion you should immediately add at least the amount you spend onto the value of your house.

And it just keeps on getting better.

Figures released in July 2006 show that a loft conversion which incorporates a bedroom and en-suite bathroom can add up to 20% to the value of your home. These figures show true to date. Click here for more information on raising property value of your home.

In London loft conversion prices usually cost up to £50,000 though throughout the UK the average seems to be around the £20,000 – £35,000 mark.
These costs are when employing a specialist loft conversion company and they can be drastically reduced by doing some of the work yourself. Much of course depends on the type of conversion. For example, a basic storage solution can often be done in just a day or two and there are some specialist loft conversion companies who will, for around £1000-2000, install joists, a new hatch, lighting and a loft ladder in just 24 hours.

But, for a full scale, and well built loft conversion, loft conversion prices are usually somewhere between £19-£50,000.

If you have any questions regarding your building or refurbishment project feel free to leave it in the comment section below.

The importance of bringing in a good, professional designer as early as possible cannot be overstated. They will come up with ideas that may never occur to you and advise on achieving your aims within your budget. They can also steer the project through development, minimising compromise so you end up as close as possible to your ambition, adding space and that elusive ‘wow’ factor, too.

The Royal Institute of British Architects has a good library in London where you can find many books and material related to house extensions, ideas for designs and planning and how to refurbish them. Find material like this, directly from proven architects is a good point to start finding ideas for your house extension project

Another idea is to study the house extension designs from well-known architects as a way of determining your extension design.

House extension in Chiswick (provided by architect your home)

You can also find a good amount of useful online home design websites. We would recommend taking a look at our house extension category for house extension ideas, galleries and planning information – we have worked hard and searched the web to give you modern house extension design ideas.

Most popular types of home extensions:

Single Storey Extensions

Extending your home with a single storey extension as opposed to moving to a new house can prove to be a more economic and satisfactory solution that suits your family’s present and future needs. A new extension is a sensible investment that can add to the value of your home and provide the additional internal space required enabling you to make the most effective use of your accommodation.

Double Storey Extensions

A two storey extension can make a substantial difference to your home, not only giving you extra space in your lounge, kitchen, dining room or other living areas, but also increasing the available bedroom accommodation or providing an additional bathroom. This type of extension often gives you enough space to avoid having to move home, at a cost which is far more affordable.

Side Return Extension

A side return extension is usually used to create extra space in existing rooms or to re-arrange your interior floor plan to create extra space that could include: bedrooms, bathrooms or living space. Side return extensions can also be combined with rear extensions to form a wrap-around extension.

Conservatory Extensions

Investing in a conservatory extension is a wise move that will add value to your property and provide room that is flexible enough to be used in a variety of ways. By purchasing a conservatory, you’re not just buying another room… ‘you’re investing in a whole new way of life.’

The Cube:

‘The Cube’ design has been developed with the following key functions in mind; sustainable development, pre-fabricated construction methods, visual impact and cost efficiency.

The major benefit of The Cube extension is that it can be installed for the same cost as a glass roof conservatory, which means you get the benefit of thermal mass construction providing great energy efficiency, large glazing with bi-fold doors and frameless skylights, allowing maximum day light penetration and amazing opportunity for evening star gazing when relaxing or entertaining.

Where do I start?

A general process for getting an extension built might be
1. Sketch out some plans/ideas yourself
2. Approach an architect and get some detailed drawings made
3. Apply for planning permission
4. Get some quotes in (can be done before planning permission if not sure on budget I guess)
5. Agree contract with builder. A useful suggestion that some people have done is to break down the payment into different sections based upon completion of job.
This is just a simplified overview, you will also need to get building regulations approval and permission (at least no dispute) from your neighbours as well.

Prices:

An extension to your house can be a easier option to moving for gaining more living space, but how much will it cost for types of extension of different sizes? See our general uk building price guide.

As a rough idea you can typically say that it will cost £1000 per m2 or  93 per ft2 including basic plumbing and electrician work. This price is per unit area of internal floor space and so a 5x4m single floor extension will have a total floor area of 20m2 and a double storey will have 40m2.

Typically, single storey house extension costs will cost more per metre squared than a double storey. In theory a triple storey would cost less still. In practise the difference in cost may be small though. The price per square metre also depends on the size of the property.

There are basic costs that don’t increase too much with size and hence the cost per square metre will decrease as the floor area increases.

We have recently added a more comprehensive list of resources for your house extension with our article House Extension Inspiration and Planning Guides Feel free to have a look! (July 2010)

The fact is that home improvement is one of the largest growth areas in our economy today. Many people today are improving there home as opposed to moving because it’s cheaper. The most common home improvement are conservatories followed by extensions and loft conversions.

Therefore, to keep a firm rein on these developments; planning requirements are getting tighter to ensure that the type of home improvement is in keeping with the surrounding houses and neighbourhood. I am sure we all agree – “nobody would wish to live next to a monstrosity”.

Approximately 60% of conservatories built will require planning permission.

Under the present legislation you may not require planning permission providing you meet with the following conditions:

• No more than 50% of the land which surrounds the “original house”* can be developed. If you require a conservatory that covers more than 50% planning permission is required.
• If the proposed conservatory faces any road, planning permission will be required.
• Maximum depth for a conservatory on a detached property is 4000 mm
• Maximum depth for a conservatory on a semi deched property is 3000 mm
• The maximum height of a conservatory is 4000 mm
• Conservatories built to the side elevation of a property a maximum of 4000 mts high and no more than 50% that of the original house
• At least 50% of area that will form the external boundary / edge of the conservatory must be glazed and 75% of the roof area to be covered with either glass or polycarbonate.(Building regulations)
• All conservatories must be separated from the house by an external quality door, patio door or French doors. (Building regulations)

Conservatories on listed building, national parks, Broads Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites planning permission will be required.

* The term “original house” means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date).

Even if you may not have had an extension built to the house, a previous title-holder may have done so.

The above mentioned only applies to extensions after the 1 July 1948.

We have listed some additional information and conditions which attract planning permission:

• If you build within 2m of the boundary line and the highest point at that junction is 4m or more high.
• If your conservatory covers more than 50% of the original garden.
• If your planning development rights have been removed.
• Grade II listed buildings. These may require a hardwood conservatory with a glass roof.
• Where a conservatory is 20m or less from a road or public footpath.
  (see sketch A)

Sketch A: Irrespective of the size of the conservatory, should the distance between points A and B be less than 20m planning permission may be required.

Shaded Area may be any of the following:

• Road
• Highway
• Motorway
• Public Foot Path
• Bridal Way
• Access to another property
• Access to other garage

Impact onto the Boundary Normally the local planning officer will be looking at the projection of the conservatory i.e. how far it will protrude into the garden, normally they are happy at about 3m projection from the original house. However, should the proposed conservatory extend more than 3m he may not look at it so favourably and ask for it to be reduced in size? The reason for this is so your neighbour does not have to look at a large brick wall more than 3m long. Hence the term impact onto the boundary.

To overcome this you may wish to include a facet to your conservatory which may help in some situations. (See sketch B) This should be done by your supplier as a matter of course.

Sketch B: You can see from this sketch that the total impact onto the boundary is 6m and you could expect the planning office to reject your application.

If planning permission is not required a letter of lawful development from the council is always a good item to obtain. So should you wish to sell your property in the future, your have proof that you have complied.