Extension Budget Review, the real number before the first quote lands
An Extension Budget Review is an independent, itemised cost estimate for your extension, loft or refurbishment, written from your drawings and current UK rates. It gives you the real number before you brief a single builder, so quotes can be tested against a proper benchmark, not hope. Typical UK turnaround: 5–8 working days from receipt of drawings.
- Itemised pre-build budget written from your drawings.
- 2026 UK rates, London, Home Counties and major cities.
- Includes VAT, professional fees, Party Wall, contingency.
- Fixed fee, typically £900–£1,800 depending on project size.
- Turnaround: 5–8 working days.
| Project value (build only) | Fixed fee | Turnaround |
|---|---|---|
| Up to £100k | £900 | 5 working days |
| £100k – £250k | £1,400 | 5–7 working days |
| £250k – £500k | £1,800 | 7–8 working days |
| Over £500k | Quoted | 8–10 working days |
What you actually get
A line-by-line budget against your architect's drawings: substructure, superstructure, finishes, services, externals, preliminaries, contingency and VAT. Each line carries a quantity, unit, rate and total, with sources noted where rates are sensitive. A one-page summary at the front gives the headline figure; the workbook behind it shows where the money goes.
Why a homeowner needs this before quoting
Most homeowners receive three quotes that disagree by 30–40% on identical drawings, not because builders are dishonest, but because they price different scopes from the same drawings. With a measured budget in hand, you can issue the same scope to every builder, compare like-for-like, and challenge the outliers with evidence rather than instinct.
Frequently asked
When in the process should I commission a budget review?
Ideally as soon as you have a planning-stage drawing pack, typically design stage or 3. The earlier the number is on the table, the cheaper any change of plan is. Even at concept stage, an order-of-cost estimate is usually worth doing before you commit to a full architectural fee.
Do you also review my builder's quote against the budget?
Yes. Once you receive contractor quotes, we can compare each against the budget on a single page, showing where each builder is high, low or missing items entirely. This is normally included in the fee for projects above £250k and quoted as a small add-on for smaller jobs.
Do you work outside London?
Yes. We work nationwide, with adjusted rate bands for the South East, Midlands, North West, Scotland and the South West. Rates and contractor cost behaviour vary regionally; the budget reflects that.
Know what your project should cost. Before you build it.
One UK working day response. Fixed-fee proposal, VAT inclusive. No retainer. No obligation.