Home extension: set yourself up for success with a good design brief

After taking the decision to extend, the first things you need to do are to produce a good design brief for your Architect and organise your design ideas in a design journal. These two documents combined are the best way to communicate the deliverables of your home extension to your Architect.

Design brief

Ask an Architect their biggest gripe when it comes to interacting with clients, and most will tell you it’s having a fuzzy picture of what the homeowner wants to achieve.

Before contacting Architects, you should organise your own thoughts as far as possible, so when you do come to explain what it is you want to achieve, you do so with clarity and purpose.

A design brief needn’t be at all complicated, although there is a balance to be struck between too little information and too much. Paint a clear picture of what you want and outline the parameters of the project (the scope), whilst not overloading the brief with too much information so as to suffocate the Architect’s design instinct. Set out the destination and let your Architect navigate the best route there.

Your design brief should be simply written and take up about a page; keeping it succinct will force you to think about what’s important. It should look something like this:

  • Why do you need more room?
  • What type of extension do you need?
  • What do you need the new space to do?
  • Who will use the it? Both now and in the future.
  • How do you feel the extension will influence the amenity of your existing home?
  • Do you envisage any ancillary work? (Solar install, bathroom refit, boiler upgrade et al)
  • Where is the line of demarcation?
  • What are your top 3 design requirements in order of priority?
  • What type of ‘look’ do you wish to achieve? (Industrial, cosy, period, lofty, traditional, minimalist, contemporary et al)
  • Are there any features of your existing home you wish to keep and extenuate?
  • Are there any specific materials, products or brands you wish to use?
  • What quality grade do you want to achieve? (top end, average, basic)
  • What are you budgeting to achieve it? (As much as it takes, the minimum necessary, somewhere in the middle)
  • What timeline are you working towards?

Your ideas will inevitably evolve so don’t sweat on getting the design brief perfect. Rather it represents a sturdy anchor point from which to start.

Design journal

In addition to the brief, start a design journal. The journal needn’t be anything more sophisticated than a scrap book. Ensure the paper is white and unlined; a clear page will help you think freely.

In your journal create a mood board for the project. Scour through design magazines and take cuttings, screenshot and print off images you that like from online home design hubs and from social media feeds (Pinterest is a particularly excellent platform for harvesting ideas), and stick them in your book. Then in the back of the book write down any and all questions that pop in your head, because when your reticular activator kicks they’ll be coming thick and fast.

A physical journal is a very tactile thing. The act of writing printing, cutting and sticking stuff in serves as a double opt-in for ideas, because you have to like it once, then like it again when you put in in your journal. This filters out the flaky ideas and leaves you with the things, objects, materials, colours, carpets, cupboards, windows, wallpaper etc. that you really do fancy.

In summary to ensure your home extension gets off to a flying start, write a pithy design brief supplemented by a lovingly-curated design journal, to help get you and your Architect on the same wavelength from the get-go.


Having distilled your initial thoughts into an edifying design brief, you can further organise your project needs by deciding on what aspects are most important and must be delivered, and what things you’d be willing to compromise on if necessary.

Brain-dump all the various aspects of the project into a single to-do list, in no particular order. Now decant these into one of three buckets:

  • The things your project must have
  • The things your project should have
  • Would you like to offset the extension’s carbon footprint with green design features? Please provide a copy of your EPC

When you get thinking about all the various pieces of work involved you will see how doing one thing will quite naturally leads to doing another. Before you know it you’ve concluded that tearing down the house and building anew is the only way to go.

Take the Smith family for example. Mum had long wanted a kitchen extension large enough to accommodate a family dining table as well as a separate utility room in which to store the dog’s accoutrements. In addition Mum didn’t think much of the Artex ceilings in the landing, or the living room’s floral wallpaper for that matter, and so suggested replastering since the Builders would already be there. Dad had always fancied marble flooring, but marble is cold to the touch so underfloor heating would be sensible, and that would need a bigger boiler to power it. He was also remembered when the Electrician warned of the fuse board not complying to current standards when he came for an emergency call out last year. Grandad would always grumble about having to climb a flight of stairs to use the loo, so he asked for a W/C on the ground floor. Whilst son lay down his demands for garden remodel so he could fit football goals in either end. And let’s not forget darling Daughter who’d just passed her driving test – she saw sense in installing solar panels hooked up to a charge point in the driveway to power her new electric car.

Thinking through the ins and outs of what your home needs can get overwhelming and very easily lead to scope creep, and before you know it your kitchen extension has turned into a total house renovation.

By decanting the work into three buckets of varying priority, you allow yourself to focus on the essentials your household needs, whilst not losing sight of the nice-to-have bells and whistles that would enhance your and comfort and enjoyment.

By prioritising the most important parts of the project from the least, you hone-in on what matters the most, allowing you to focus your time, and importantly budget, to achieving these without compromise.

If you would like some free planning advice, get in touch with us.