For UK Homeowners · The Extension Guide
Your quoteis missingthousands.
Not because your builder is dishonest — because you don't know what to ask for. Yet.
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What most quotes leave out
The average UK extension goes over budget by £15,000 to £30,000.
The bad decisions
Choosing the cheapest builder quote, misunderstanding party wall laws, failing to budget for VAT, or signing a contract that doesn't include waste removal. These are the classic errors that turn a dream project into a nightmare.
The £19.99 insurance policy
For the price of a few cups of coffee, you get the blueprint to managing a project properly. Knowing the right questions to ask your architect and your builder will save you thousands of pounds and months of stress.
What's Inside
Nine clear, no-nonsense chapters covering the entire lifecycle of a typical UK residential extension.
Planning Permission
When you actually need it, and how to get it without endless council delays.
Finding Builders
How to spot the cowboys and secure the tradesmen the architects use.
Budget Management
The hidden costs no one mentions until the foundations are poured.
Party Wall Agreements
Keep your neighbours happy and avoid legal disputes that halt work.
Building Regs
The crucial difference between planning and building control.
Design & Drawings
Getting what you want on paper before it's set in brick.
Timeline Planning
A realistic schedule, not the optimistic one builders quote.
Common Mistakes
The classic errors that add thousands to a typical UK extension.
Pre-Start Checklist
Everything that must be in place before the first skip arrives.
See what you're getting
A professionally formatted PDF you can read on screen, print, and keep with your project notes.
Free Property Check
What do you know
about your property?
Land Registry · Environment Agency · Planning Data (MHCLG) · postcodes.io
The builder pricing checklist
Before you sign any contract, work through this item-by-item. Every unticked row is a potential variation order — money out of your pocket mid-build.
Planning application fee included (or confirmed not required)
Building regulations application fee
The scope gaps that cost homeowners thousands
These are the items builders routinely leave out of quotes. You only discover them when the invoice arrives — or when the plaster is already on.
Sockets on the island unit
Island sockets are almost never included in a standard kitchen extension quote. Adding them after the screed is laid can cost £400–£800 extra.
Skirting boards and architraves
Most builders quote to build the shell. Skirting, architraves, and door casings are often a separate allowance — or simply left off entirely.
Trusted by homeowners across the UK
We were quoted £65,000 for a single-storey rear extension. This guide made us realise we hadn't budgeted for VAT, structural calculations, or the party wall surveyor. It saved us from starting a project we couldn't afford to finish.
The section on vetting builders is gold. We used the exact questions provided, and it became immediately obvious which builder was just telling us what we wanted to hear. Worth twenty times the price.
Calm, practical, and incredibly reassuring. We felt entirely overwhelmed by the council's planning portal. This guide translated the process into plain English. The extension is now underway and we're sleeping soundly.
Ready to start?
Get the complete guide instantly. No fluff, no jargon, just the solid advice you need to get your extension built right.
- Immediate PDF download
- 9 comprehensive chapters
- Printable snagging template
- Builder pricing checklist
Common Questions
What if I'm not happy with the guide?
We offer a 14-day money-back guarantee, no questions asked. If the guide doesn't deliver for you, use the contact form below and we'll refund you in full — no hoops, no conditions.
Is this relevant for my part of the UK?
Yes. The planning framework varies slightly between England, Wales, Scotland, and Northern Ireland, but the fundamental principles of managing builders, budgeting, and project sequencing apply everywhere. Where laws differ (like Building Warrants in Scotland), we note it.
Is it a physical book?
No, it's an immediate PDF download. You can read it on your phone, tablet, or print it out to keep with your project notes.
Does this replace an architect?
Not at all. This guide is designed to help you brief your architect better, understand what they're doing, and manage the process. It makes you an informed client.
I'm only doing a small extension, do I need this?
Even a small porch or conservatory can run into thousands of pounds in hidden costs if building regulations or party wall agreements are mishandled. The smaller the budget, the less room there is for expensive mistakes.
Get in touch
Questions about the guide, trouble with your download, or want a refund? Send us a message and we'll get back to you.