The cost of building an extension on your house

Building either a single or double storey extension is a great way of growing your home if you’re looking to gain a bit more room to live in. Not only can you add (sometimes much needed) extra space, but in doing so, it’s likely that you’ll significantly enhance the value of your home and make it more appealing to future buyers.  Unless there is significant negative equity in your property, it’s fair to assume that any money you spend on extending your home is likely to repay you when the time comes to sell. A quick search on the internet should help you find a good quality local builder.

But just how much does it cost to build an extension to your home?

Of course, if you want more than a general idea of price – which is the best that this guide will offer, most local builders will happily provide you with a no obligation free estimate, but, as at April 2011 you can work on an estimated price of somewhere between £1,000 to £1,200 per m2 to build an ‘average’ extension on your home.

Of course, this figure can vary significantly depending on the type of building material you choose (prices vary hugely between brick, stone and cement rendered breeze block) and what kind of roof you put on the extension – again, the cost of building a flat roof is different from building a pitched roof – plus a number of other variables to consider.

The cost per m2 that we’ve explained above should include basic plumbing and electrical work (we refer to it as 1st fix), but it won’t include any bathroom furniture or kitchen units. You’ll need to add these in to the overall cost yourself once you have had a price to purchase and then fit bathrooms and kitchens. We’ve taken the liberty of adding in some average costs for kitchens and bathrooms a little further down the page, although it must be remembered that prices can vary hugely dependent on the size of the rooms being fitted and the quality of the furniture you buy.

Architect and Structural Engineer Costs

Building a good quality extension to your home requires a significant amount of thought, planning and creativity. If you want to ensure that you get the design right we highly recommend using the services of a good quality architect – someone who understands what you’re looking for and understands the demands and requirements of your local council. Choose your architect carefully – like anything in life, there is good and bad.

Once you’ve found your architect, you’ll also need the services of a structural engineer to make sure that the extension being built is strong enough to hold the weight of a new roof.

You can expect to pay around £800 to £1,000 for your architect drawings and structural engineer reports, then an additional £400 – £500 for building regulations.

The cost of an extension will vary on:

  • Whether you choose to have a single or double storey extension  (single storey can be more expensive per m2)
  • If you use handmade brick or expensive stone to extend your property
  • If you choose special handmade hardwood windows or standard UPVC windows
  • Building foundations or RSJ steel supporting beams necessary to make the extension safe
  • The cost of a fully fitted kitchen or bathroom (if that’s the room you’re creating
  • The kind of roof you choose to put on your extension

There are also non-build costs to consider, such as:

  • Kitchen and kitchen appliances – allow anything up to £12,000, but this can be much more or much less, due to a number of factors
  • Bathrooms – allow around £1,000 to £3,500 per bathroom fitted, but again, this depends on many things such as quality of furniture, amount of tiling, cost of tiles etc.
  • Decorating – (depending on whether you’re wallpapering or painting) around £10 – £15 per m2
  • Floors – between £10 – £80 per m2
  • Unplanned extras, including extra light ad plug points, Internet cabling, telephone points and more – budget to allow 2-4% of the overall cost, just to be safe.

Remember, it’s highly likely that you’ll need to get planning permission and approval of building regulations from your local council before you commence any work on your new extension. Not doing this can be the most costly mistake you could make.

Why not contact a professional builder Leeds to get a fixed quotation? They rarely charge to come out to view a property; they can offer advice, help and steer you away from problems which you may not have considered.

About the author: Paul Jefferson has many years of building experience under his belt, so if you require a builder in Leeds then why not get in touch. why not visit FMB the UK’s largest trade association in the building sector for more information on builders.

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