The Homeowner’s Survival Guide to Extensions
Undertaking an extension is one of the best ways to create more space in your home, improve your day-to-day living, and add value to your property. But while the rewards are significant, the process can also be complex — and there are common pitfalls that many homeowners don’t anticipate.
As an interior designer and business owner, I’ve supported clients through countless renovations and extensions, and I know first-hand the things that can make or break a project. Here are my top tips to help you approach your extension with confidence.
1. Understand the Difference: Planning Architect vs. Practising Architect
A recent client of mine learned this lesson the hard way. They commissioned an “architect planner” who produced simple drawings for planning permission. Unfortunately, the plans were inaccurate, the service was unprofessional, and when we re-measured the site, we discovered major errors.
Some services exist purely to help you pass planning permission — but that doesn’t mean the drawings are suitable for construction. Always ensure you’re working with a qualified, practising architect who can deliver plans fit for the build itself.
2. Planning Permission or Permitted Development?
While most people have heard of planning permission, fewer understand the nuances of permitted development rights. For example, you may be allowed to extend three metres out, but your pitch height could be restricted to three metres as well. And on newer developments, permitted development rights may not apply at all.
A good architect will guide you through this, but it’s important to go in with your eyes open.
3. Timing: Who to Involve and When
A reputable contractor won’t provide a full quote until you have planning permission and structural engineer’s drawings in place. This can affect your timeline — and remember, experienced main contractors are often booked up six months or more in advance. Factor this in early so you’re not left waiting.
4. Don’t Forget the Party Wall
This is one of the most commonly overlooked aspects of a build. If you’re extending along a shared wall, you’ll need a party wall agreement. Sometimes this process is straightforward, but it can also be contentious. Leave at least six weeks to secure agreements — and be prepared that if your neighbour disputes, you could end up paying for both your surveyor and theirs.
5. Budget, Budget, Budget
It’s easy to get caught up in the big-ticket items — like a £30k kitchen — and forget the many hidden costs: flooring, paint, furniture, windows, doors, even grout and sealant.
Always build a detailed budget that factors in the whole picture and add a minimum 10% contingency. Working with an interior designer can help you avoid overspending, spot hidden costs, and make informed decisions at each stage.
6. Choose Your Suppliers Wisely
If you’re living in your property during the renovation, the “bedside manner” of your tradespeople matters just as much as their craftsmanship. Respect, communication, and professionalism will make the experience far more manageable — and keep your sanity intact during the messiest stages.
Final Thoughts
An extension is one of the most rewarding projects you can undertake as a homeowner — but only if you approach it with clarity, realistic expectations, and the right team around you.
At Debs Bespoke Interiors, we support clients at every step of the journey: from design and planning, to selecting trusted partners, through to managing the entire renovation. If you’re thinking about an extension or renovation and want to talk it through, get in touch — we’d love to help.
