How much do building regulations cost?
Building control fees depend on the project value and type. Estimate a typical building-regs cost below.
What building control covers
- 1Plan check
Your drawings and structural calcs are checked against the building regulations before work starts.
- 2Site inspections
Key stages (foundations, structure, insulation, drainage, completion) are inspected on site.
- 3Completion certificate
Sign-off produces a completion certificate — essential for resale, refinance and letting compliance.
The completion certificate building control issues is what a buyer's solicitor and a refinancing lender will ask for — so it's not optional paperwork, it's what makes the value real. Budget the fee and keep the certificate with the property file.
Building regulations costs (indicative)
| Project | Basis | Indicative cost |
|---|---|---|
| Small works (e.g. knock-through) | fixed | £300 – £600 |
| Single-storey extension | fixed | £600 – £1,000 |
| Loft conversion | fixed | £700 – £1,200 |
| Larger / multiple elements | by value | £1,000+ |
Charged by the local authority or a private approved inspector; covers plan checking and site inspections.
Frequently asked questions
How much do building regulations cost?+
Building control fees for domestic work typically run £300–£1,200 depending on the project — a knock-through at the lower end, a loft conversion or extension higher. It covers plan checking and site inspections.
Is building regs the same as planning permission?+
No — planning permission is about whether you can build it; building regulations are about whether it's built safely and to standard. Many projects need both, and they're charged separately.
Related tools & guides
Want to know how these figures are calculated? See our cost methodology.
Cost figures shown are indicative estimates, not quotations. You are responsible for verifying all costs (obtain contractor quotes) and any figures submitted to a lender. ScopeWise is a documentation tool, not financial, tax, structural or planning advice. HMO compliance prompts are guidance only — confirm requirements with your local council, as standards and licensing vary by authority.