Talk the job through with a builder before you spend
You have a number from a calculator and an idea of what you want. This is the conversation that turns it into a plan — what is realistic, what it should cost, what order it happens in, and what to ask the builders you are about to call.
Feasibility discussion with a builder — £59Book here, then send your sketch, drawings or photos by WhatsApp or email · money-back if it isn’t clear
Send what you have — a sketch, photos, an architect's drawing, or just a description. Within 24 hours you get:
- A straight answer on whether what you want is realistic in that house
- A realistic budget range for the job as you have described it, and where the money usually goes over
- The consents it needs — planning or permitted development, building regulations, party wall, a structural engineer
- The order the work has to happen in, and what needs deciding before anyone starts
- What to put in front of builders so the quotes you get back can actually be compared
- A one-to-one call to talk it through
£59 for one property or one quote. No quotations for the work, no referral fees, no upselling.
A calculator gives you a number. This tells you what the number is hiding.
Most projects do not go wrong on the headline build cost. They go wrong on the things nobody priced — the drainage that has to move, the steel that needs a bigger pad, the six weeks of design and consent before a single brick moves. This is what an hour of a builder’s attention buys you before you commit.
For 18m² with bi-folds and a rebuilt kitchen, £52,000 is optimistic outside London — £68,000–£85,000 is the honest range for the spec you have described. The gap is mostly glazing and the kitchen, and both are choices you control.
Your photos show the soil stack exactly where the new opening goes. Moving it means a new connection and possibly a manhole inside the extension footprint — £1,800–£4,500, and a variation if it turns up mid-build instead of on the drawings.
4m on a detached, 3m on a semi, unless you use the larger-home prior approval route. Yours reads as permitted development, but get a lawful development certificate — it costs little and your buyer’s solicitor will ask for it in ten years’ time.
Ben Murrell
I’m a carpenter by trade and I’ve spent nearly 30 years on UK building sites. When you book, I go through what you send and I’m the one who rings you. I never quote for the work I review and I take no referral fees, so there’s nothing for me to gain by making a problem sound bigger — or smaller — than it is.
What people planning work say
“Ben was incredibly lovely and helpful with some questions about our property and responded quickly and thoroughly.”
“Thank you very much for the detailed advice regarding the kitchen and lounge wall; it was incredibly helpful and gave me a much clearer understanding of the structural requirements and building regulations involved.”
“Incredibly helpful, clear informed advice. Would recommend.”
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What this review can and can’t do
We can
- Tell you whether the plan is realistic, and what it should cost
- Point out what the calculator and the quotes have left out
- Tell you which consents and specialists you actually need
- Give you the questions that make quotes comparable
We can’t
- Design it or produce drawings — that is an architect or technologist
- Guarantee a planning decision or a building control sign-off
- Visit the site, or quote for the work — we never do the work we advise on
- Give a fixed price for your job; you get ranges and what drives them
Full detail in our terms.
Before you book
I only have a rough idea. Is that enough to send?
Yes. A description and a few photos of the space is enough to get a useful answer. Drawings help, but plenty of people book this before they have spent anything on design — which is usually the cheapest time to find out the plan does not work.
Is this a quote?
No, and it never will be. We do not carry out the work we advise on, so we have no reason to talk your budget up or down. You get ranges, the reasoning behind them, and the questions to put to the builders who will quote.
I already have quotes. Should I book this or the quote review?
If you have the quotes in your hand, book the quote review — it is the same £59 and it reads the actual documents. Book this one when you are still deciding what to build, or when the quotes are so far apart that the question is really about the job, not the paperwork.
My builder has started and something has gone wrong. Does this cover that?
Yes — book this and say so. Mid-job problems and arguments about workmanship are the same £59: you send photos and the paperwork, and you get an independent read on whether the work is acceptable and what best practice says.
Who reads it?
Ben Murrell, a builder for nearly 30 years. The person who reads it is the person who calls you.
What if it does not help?
If the discussion does not give you a clear answer on what you sent, you get a full refund. No forms.
Feasibility discussion with a builder — £59
Useful first: See how the advice looks · Extension cost calculator · Already have quotes? Quote review · Only one thing to ask? Ask one question free.
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