One team to design, cost and build your extension — start to finish
No juggling architects, quantity surveyors and separate contractors. With OPB’s design & build service you get one plan, one budget and one accountable team — from the first sketch to the final coat of paint.
The problem with the usual way
Most extension projects go wrong in the gaps between people
Hire an architect, then find a builder, then hope they agree. It’s the standard route — and it’s where budgets blow out, timelines slip and stress builds. When something’s unclear on site, the architect blames the builder and the builder blames the drawings. You’re left in the middle.
Budgets that drift
Designs drawn without a builder’s input often can’t be built for the money you were quoted.
Finger-pointing on site
When designer and builder are separate, every problem becomes someone else’s fault.
A finish that disappoints
Detail gets lost in translation, and the end result rarely matches the vision you started with.
The OPB way
Design and build, joined up under one roof
Because the same team designs your space and then builds it, the drawings are grounded in what’s actually buildable and affordable. Everyone understands the intent behind every detail, and you have one number to call for the entire project.
The result is a smoother build, a budget that holds, and a finish that lives up to the vision you started with.
How it works
Four stages, one team the whole way
Design
We understand how you want to live, then develop drawings that make the most of your space and light — tested against real family life and a realistic budget.
Plan & cost
We cost the whole project properly and agree a clear, transparent budget, handling planning, building regs and scheduling so you always know what’s next.
Build
Paul is hands-on and on site, keeping every trade flowing to the next. Our long-trusted contractors take real pride in their work, and it shows.
Finish & handover
We see every detail through to the last coat of paint and hand back a space that’s ready to move straight into and enjoy.
The whole team made what could have been a stressful process genuinely enjoyable — we now have exactly the family kitchen we always wanted.
Free guide
The Homeowner’s Guide to Planning an Extension
Budgets, timescales, planning permission and the questions to ask before you commit — everything we wish every homeowner knew before starting. Free, no jargon.
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Ready to start?
Book a design consultation
A relaxed, no-obligation chat about your project, your budget and what’s realistic. In person at our Heswall office, or over a call.
Get in touch
Start your design & build project
Tell us about your project and we’ll arrange a no-obligation design consultation.