How to brief an architect for a sustainable home extension in London
The brief you give your architect at the start of a project determines almost everything that follows. Get it right, and the design process is a genuine collaboration toward a shared goal. Get it wrong, or leave it too vague, and you’ll spend the middle stages of the project renegotiating things that should have been settled at the beginning.
Sustainability is one of the areas where this matters most. It’s much easier to build a sustainably specified extension when the ambition is agreed upfront than to retrofit sustainability credentials onto a design that was conceived conventionally. Here’s how to approach the brief.
Start with your values, not your specification
You don’t need to know the difference between SIPs and CLT before you pick up the phone. What you do need to know is what you care about, and how much.
Do you want to minimise the carbon your extension puts into the atmosphere? Do you want low running costs? Do you want natural, beautiful materials? Are you interested in the provenance of what gets built into your home? Are you willing to pay a premium for a better building, or is the budget fixed and you need the architect to work within it creatively?
These are the questions worth thinking through before the first meeting. A good sustainable architect will draw out the answers through conversation, but arriving with some sense of your own priorities saves time and makes the early design stages more productive.
Five questions to ask before you appoint
Can you show me a completed sustainable extension project and explain the specific carbon and material decisions you made? (Look for real examples, not aspirational statements.)
How do you approach embodied carbon, and at what stage do you start making specific material recommendations?
What’s your approach to reclaimed and natural materials, and do you have supplier relationships that make these viable within a normal budget?
How do you handle the relationship between a sustainable extension and the existing building — particularly around breathability and moisture in older London homes?
What does your fee include in terms of sustainability specification and coordination with contractors?
The answers will sort the practices that genuinely work this way from those that have added sustainability language to their website without changing how they design.
What a good brief looks like
A brief for a sustainable extension doesn’t need to be long. It needs to be honest about priorities and constraints. Something like:
“We want to reduce the embodied carbon of the build as far as the budget allows. We’d like to use reclaimed materials where possible, particularly for the facade. We want the extension to be warm, well-insulated and low-cost to run. The budget is £[X] and we understand that sustainable specification may cost slightly more, but we’re committed to the approach.”
That’s enough to start a productive conversation. Everything else can be developed through the design process.
How New Makers Bureau runs its early design process
We start every project with a workshop, not a presentation of our ideas, but a conversation about yours. We want to understand the building, the site, how you live, what’s working and what isn’t, and what you want the extension to do for the next twenty years.
From that conversation, we develop an initial brief document that captures the priorities, constraints, and sustainability ambitions. We share it back with the client before we start drawing. If we’ve understood you correctly, we proceed. If we haven’t, we correct it. That document then sits behind every design decision we make.
Red flags
A few things that suggest a practice isn’t genuinely oriented toward sustainable design:
They talk about sustainability in terms of features (solar panels, heat pumps) rather than fabric and materials.
They can’t show you a completed project with real material and carbon decisions.
They don’t ask about the existing building, only about the new extension.
They suggest sustainability is something to add to a design once the main decisions are made.
Sustainable design isn’t a layer applied on top of architecture. It’s the way the architecture is made. The brief is where you establish that.
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