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by Imran Jahn on Aug 9, 2025
Most projects are decided, for better or worse, in the first few questions. Can we extend? Will the council wear it? What are we actually dealing with on this site? We treat those early questions as the real start of the work, not a formality to get past.
A feasibility study and, where it helps, pre-application advice are where a project's biggest risks and best opportunities show up, while it's still cheap to act on them.
Front cover of a Stage 2 Feasibility Report by RISE Design Studio, outlining a clear, sustainability-focused approach to early-stage project planning.
What feasibility actually means
Feasibility isn't a guess or a polite "probably". It's a proper analysis of a site that gives you the full picture before you commit time or money. It covers what's physically possible on the site, how local and national policy applies to it, whether you need planning permission or can use permitted development, where the risks sit (from overshadowing a neighbour to awkward access), and how the sustainability goals can be built in from the start rather than added later. It usually ends with a clear view on whether it's worth going to the council for pre-application advice.
Real conditions, not just paper plans
A proposal can look good on paper and still be difficult to build. The useful part of feasibility is thinking like a builder and a planner as well as an architect: looking at the structural logic and the site levels, how materials and machinery will actually get in, likely drainage problems, trees, rights of way and shared boundaries, and how the building sits to the sun. None of this is about narrowing ambition. It's that the decisions made now are the ones that save you from expensive surprises later, and a building with fewer surprises is usually a better, lower-energy one.
Reading the planning context properly
Planning in London, and across the UK, is never one-size-fits-all. Every borough has its own character, and a rear extension that sails through in one postcode can stall in the next. So the advice has to be specific to the site. We look at whether it's in a conservation area or covered by an Article 4 direction, whether it's listed or affects the setting of a listed building, what happened on previous applications on the site and next door, the relevant design and heritage policies, and the local precedent, which is to say what's been refused nearby and why. The refusals often tell you more than the approvals. We turn all that into plain advice rather than planning jargon.
Concept design: ideas that fit the place
Once the opportunities and constraints are mapped, we start sketching. Not detailed drawings, but tested concepts with just enough substance to judge them against. That might mean working out whether a rear extension, a side return or a loft conversion adds the most for the money, testing massing and layout on a small new-build plot, or seeing how reorganising the inside, moving the kitchen to the centre or relocating a stair, could change the light and the way the house works. Each option comes with a note on the likely planning route, the structural challenges, and how it stacks up against the budget. You get to see the road ahead before deciding how far to go down it.
When a pre-application is worth it
A pre-application submission lets you test an idea with the council before committing to a full application. It isn't binding, but it's useful. It's worth doing when you're in a conservation area or working with a listed building, when you want to push at local policy with a strong design argument, when the neighbours are likely to object, or when you're introducing modern materials or forms into a traditional street. We handle the submission and the dialogue with the officer, so you enter the formal process having already taken out the main uncertainties.
Permitted development or full planning
The question we hear most is whether planning permission is even needed. The answer depends on where the property is, whether it's listed or in a conservation area, the size, height and position of what you're proposing, what's been removed by any Article 4 direction, and whether the work changes the use, form or character of the building. Where permitted development applies, we can apply for a Lawful Development Certificate to put it beyond doubt, which is worth having for a future sale or a mortgage. Where full planning is needed, we take you through it.
Who feasibility is for
The earlier you ask the big questions, the better the answers tend to be. Feasibility and pre-app work suit homeowners planning an extension or loft, renovators unsure what the planning constraints are, and buyers who want to understand a property's potential before they commit to it, which is often the most valuable time to do this work. It's particularly worthwhile on listed buildings and sensitive sites, on small or awkward plots like mews and infill, and where the priority is more daylight, better thermal performance or low-energy systems. Small projects often carry the biggest proportionate risk, and the point of this work is to take that risk out early.
How it fits the RIBA stages
We fold feasibility into the early RIBA stages, because a good project is decided well as much as designed well. Stage 0 sets the ambitions and reviews the planning context. Stage 1 is the feasibility study itself: site analysis, policy review and sketch options. Stage 2 develops the preferred option into proper concept plans, with the sustainability worked in from the start. It keeps the early process lean and logical, so you're not paying for detailed design before you know the project stands up.
Feasibility isn't about limiting what you do, it's about knowing what you're dealing with before you commit. Once the planning, technical and cost picture is clear, you can decide with confidence how far to take it. If you're thinking about renovating, extending or building something new, we'd be glad to talk it through.
→ Email us at architects@risedesignstudio.co.uk
→ Or call the studio on 020 3947 5886
Frequently Asked Questions
What is a feasibility study?
It's an early analysis of a site that tells you what's realistically possible before you commit to a full design. It pulls together the physical constraints, the planning position, the likely risks and the sustainability options into one clear picture, usually with a recommendation on whether to approach the council for pre-application advice.
What's the difference between feasibility and pre-application advice?
Feasibility is our assessment of what the site can take and what the policy says. Pre-application advice is the council's own early view on a specific proposal. The two work together: we'd often use a feasibility study to decide whether a pre-app is worth doing, and what to put in front of the planners if it is.
Is pre-application advice binding?
No. It's the planning officer's informed view at an early stage, not a decision or a guarantee, and it can be qualified or change. It's still valuable, because it surfaces the council's main concerns before you've spent money on a full application, so you can design around them.
Do I need planning permission, or is it permitted development?
It depends on where the property is, whether it's listed or in a conservation area, the size, height and position of the work, whether any permitted development rights have been removed by an Article 4 direction, and whether the work changes the use, form or character of the building. Part of feasibility is establishing exactly which route applies to your project.
What is an Article 4 direction?
It's a step a council can take to remove permitted development rights in a particular area, often a conservation area. Where one applies, work that would normally be permitted development needs full planning permission instead, so it's one of the first things worth checking.
What is a Lawful Development Certificate?
It's a formal confirmation from the council that your proposed work is lawful as permitted development and doesn't need full planning permission. It isn't mandatory, but it puts the position beyond doubt, which is worth having when you come to sell or arrange a mortgage.
Should I do a feasibility study before buying a property?
It's often the most valuable time to do one. Understanding what a property will and won't allow before you commit to buying it can change the price you're willing to pay, or steer you away from a site whose constraints would block what you have in mind.
How much does a feasibility study cost, and how long does it take?
Both depend on the size and complexity of the site and how many options you want tested, so we agree a fixed fee and scope up front rather than leaving it open. It's a small cost relative to the project, and the point of it is to take risk out before the larger spending starts.
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