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The most common way any homeowner will develop their property is with an extension and the first thing that everybody asks is - how much will my extension cost?

Well, I’m not going to tell you! What I will do is provide you with some information and advice, that will help you take a much more informed approach to this, or for that matter, any kind of building project.

Now, we’ve all heard loose figures being banded around “£1000 per square metre”, “no - I heard £1500 per square metre and half that for the first floor”. The more realistic figure and the amount I normally quote to people who ask is - £1200 per square metre. But at the end of the day, what does that even mean? Well, it’s little more than a starting point really.

The thing with the largest affect on the cost is - “YOU”.

Everything is down to the decisions you make - did you plan it correctly? did you communicate your ideas clearly? Did you choose the right professionals? Did you make the most out of them? Did you change your mind? Did you blow the budget on indulgent items?

The best way to make sure you stick to your proposed budget is to plan and communicate.

There’s a common misconception nowadays that you don’t need an architect, but taking your time getting the design right and making sure you have the documents you need to communicate that vision to your contractors, is very important and in my opinion - essential. I mean, who wants to arrive home from a hard days work to find that the builders have done something you didn’t want, because they misinterpreted your description. If you have to do anything twice - it’s cost you money! This then causes extra stress and can often lead to a breakdown in the relationship between you and your builders - and nobody wants to end up here!

Then you’ve got the costs which nobody seems to mention - the general running, heating and maintenance costs. It’s all very well cutting back on materials to save on the build costs, but if it then costs you £500 extra per year to heat and maintain it, that initial saving won’t take long to dwindle away and become a constant burden.

So how can a professional help?

Firstly by getting the design right and that is a collaboration between you and your chosen design professional. You need to give them a brief and the criteria for what you want to get out of the space - but let them input on the layout and advise on the materials and appearance. You need to remember that there are practical issues to consider as well, plumbing services, man hole covers and design elements to appease local planners. So just bear in mind that you can’t always have what you want.

Something I always say to my clients is that you will start any project with 10 things you want to achieve and my advice is to go with the scheme that gives you 8 out of 10 and even drop the feature you valued the most “if necessary”. The most common problem us designers face, is that a client gets fixated with one element over all others and will try to work it in at a sacrifice to many other important factors.

Some people might not want to disagree or tell a client their ideas are no good - but I wouldn’t be doing my job if I didn’t.

Secondly by giving you good advice on the underlying materials - structural method, insulation, lighting and practical materials. You’ve got to think of the future and efficiency, as well as initial cost. All of these being equally important in my opinion.

You should consider asking your design professional to provide you with a full technical specification breakdown of materials. This will come at a cost - but should save you money in the long term, as it should enable contractors to give you a fixed price quotation and should also cut out any variables in their quotes, so you are comparing “apples with apples” so to speak.

And whoever heard of a builder turning round at the end of a project and saying “oh, the estimate I gave you for the work was too high - here’s £5000 back” just isn’t going to happen. So pin them down to a price in advance and you know where you stand.

Finally - by helping you. That statement might sound silly, but the simplest things are often the most important. They can help you professionally - and at a price, by offering project management services. But this isn’t often necessary on a typical extension project. I’m just talking about being “a phone call away” throughout the build by letting your client ask all the silly questions they need and making them feel comfortable about doing it. I never cut off ties with my clients just because they have stopped paying me - my advice to them is free to give and always available. At the end of the day, I have built up a relationship with them and I genuinely want their projects to go well, because I have a passion for my work! Plus, there’s no better form of advertising than a good referral.


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