There are many things to think about when you are deciding to turn your house into your House Extension costdream home. Have I got enough room? What will the layout be like? What colour should I paint it? Will I have room for that amazing roll-top bath? But before you get carried away with interior design schemes or pre-ordering the biggest ever TV for your new man-cave, one of the first questions that you should ask yourself is – how much will it cost?

Obviously, there is no way to completely predict the cost of a home extension, as each building project is different. For example, one extension may require much deeper and sturdier foundations than another, one may require a complete re-wire whereas another may have excellent wiring but involve much more complex plumbing. Prices for extension projects vary significantly depending on factors such as the size, number of storeys, specification and which part of the country you’re building in.

Types of Home Extensions

  • Single storey extensions
  • Multi-storey extensions
  • Semi-detached extensions
  • Kitchen extension
  • Bathroom extension
  • Garage conversion
  • Loft conversion
  • Basement extensions

Average Single-Storey House Extension Costs

However, as a very rough guide, the Royal Institution of Chartered Surveyors (RICS) suggests that the average cost of an extension is between £1,260 and £1,680 per square meter. This is to achieve a plastered finish but will exclude the price of any flooring, decoration, new kitchen etc. So according to these figures if you were thinking of building a 25 square meter single story extension this would cost between £31,500 and £42,000.

Two-Storey House Extension Cost

A double-storey extension won’t cost much more per m2 than a single-storey extension. That’s because, aside from the extra interior fixtures and finishes, you are only adding walls and floor joists. A roof and foundations are required whether you build a single or two-storey extension.

Average Cost of Garage Conversion

One of the cost-effective ways to have more practical space in your home is to convert an existing garage into a brand-new room. You can even have a partial garage conversion, so you’ll still keep some storage space, with a stud wall in place to give you living space too.

For those looking for a quicker, cheaper option that adds value to a home you can’t do better than converting a garage.

Cost of loft conversion

On the other hand, if you were thinking of extending your living space with a loft conversion, RICS suggests a guide cost of between £660 and £900 per square metre. Giving that an average-sized loft is estimated at 35 square meters, this would give you a final cost of around £23,100 and £31,500. But again this is before you have taken into account the costs of decorating, flooring, new furniture etc.

Semi-detached house extension

Semi-detached extensions are some of the most commonly completed extensions and carry similar costs to other extension types. The biggest thing to consider is that you may need to secure a party wall agreement if the work will be conducted on or near a shared wall.

Kitchen extension cost

Kitchens are even more specialist than bathrooms, so the cost of your kitchen extension will be higher than a standard extension. In addition to plumbing, you’ll need gas and electrics, plus extra costs will be incurred if you plan to purchase a new boiler or move a boiler.

Bathroom Extension Costs

Increasing the space of an existing bathroom that could be used to install a walk-in shower, extra sinks or more. These are some of the most expensive extension types, due to the added complexity of additional plumbing, fixtures and furnishings.

Cost to add a basement extension

By far the most expensive extension type, basement extensions are growing in popularity in the UK, as an excellent way to increase property values in space restrictive areas. If space is at a premium, or other above-ground extension options have been exhausted, basement extensions are a valuable option.

Much of their cost is driven by the considerable groundworks (including moving pipes and tree roots) and creating a watertight shell. As these are highly specialised tasks, it means there’s very little room for DIY works to bring the cost down.

Of course, the only way that you will really know how much your extension is going to cost is to get at least 3 proper written quotes from reputable building companies. Here at Wisecraft Ltd builders in Bolton, we pride ourselves on providing the very best quotes possible for our clients. We will ensure that we take the time to properly talk through your options to find a price and extension type/layout that suits you. Our quotes also promise to be fully comprehensive – so that means no hidden extras! And if an unforeseen issue should arise, we will ensure that nothing is done without your knowledge and permission and that any extra costs are clearly explained and quoted.

So if you are wondering, how much will my extension cost? Contact Wisecraft Ltd today for a free, no-obligation quote.