The short answer
Building-regulations drawings — the detailed technical set that shows how the work is actually built — are usually charged as a fixed fee, typically in the four-figure range for a residential extension or loft, rising with the size and complexity of the project. They're a separate stage and fee from the planning drawings: planning drawings prove the proposal is acceptable; building-regs drawings prove it's built safely and to the Building Regulations. The set covers things like construction details, insulation, structure, drainage, ventilation and fire safety. It usually needs to be coordinated with a structural engineer's calculations for any beams or structural changes, which is a separate cost. The fee does not include the Building Control application fee paid to the council or an approved inspector.
After planning, most projects need a second, more technical set of drawings before a builder can start properly. Here's what building-regs drawings cost, what they include, and why they're separate from planning.
Building-regs drawings at a glance
- Typical chargeFixed fee, four figures
- StageSeparate from planning
- ShowsHow it's built, not just what
- Often needsStructural engineer (extra)
- ExcludesBuilding Control fee
What building-regs drawings include
Building-regulations drawings are the technical layer the builder and Building Control need. They typically show:
- Construction details: how walls, floors and roofs are built up, including foundations.
- Insulation and thermal performance: meeting the Part L requirements for energy efficiency.
- Structure: beam positions and sizes, usually based on a structural engineer's calculations.
- Drainage: foul and surface-water runs.
- Ventilation, fire safety and means of escape: meeting the relevant Parts of the Building Regulations.
- Specifications and notes the contractor builds to.
Where planning drawings answer 'what does it look like and is it acceptable?', building-regs drawings answer 'exactly how is it built, and does it meet the regulations?'. That's why they're more detailed and form a separate piece of work.
What it typically costs
Because it's a defined deliverable, building-regs drawings are normally quoted as a fixed fee. The figure scales with the project — a simple single-storey extension is less work than a two-storey extension, a loft with structural alterations, or anything with complex drainage or fire requirements. The table is an indicative steer only; get a written fixed-fee quote for your job.
| Project type | Indicative building-regs fee | Notes |
|---|---|---|
| Single-storey extension | Lower four figures | simpler construction |
| Two-storey extension | Mid four figures | more structure & detail |
| Loft conversion | Lower–mid four figures | fire/escape, structure |
| Complex / large project | Higher | drainage, fire, multiple trades |
Indicative UK figures for guidance only — get a written fixed-fee quote. Excludes Building Control fee, structural engineer and VAT. Source: Checkatrade and HomeOwners Alliance cost guides.
How it fits with planning and the engineer
For most home projects the paperwork runs in two phases. First, planning: design plus the planning application drawings, to get permission in principle. Then, building regulations: the detailed technical drawings plus a structural engineer's calculations for any beams or load-bearing changes, submitted to Building Control. The architect's building-regs fee covers the drawing set; the engineer's calculations are a separate appointment, and the Building Control fee is paid to the council or an approved inspector.
You can sometimes save by appointing one professional to take the project all the way through both stages, since they already know the design. Conversely, some homeowners get planning drawings from an architect and then use a design-and-build contractor or a technologist for the building-regs set — that can work, but make sure responsibility for coordinating the engineer and satisfying Building Control is clearly assigned to someone. The key point is that planning approval and building-regs approval are two different sign-offs: you need both, and the building-regs drawings are the part that lets the builder actually start work to a checkable standard.
Why the building-regs set is worth getting right
It can be tempting to treat building-regulations drawings as a box-ticking formality after the excitement of planning, but they're the set the builder actually works from, so their quality directly affects how the job goes on site. A thorough, well-coordinated building-regs package answers the questions a contractor would otherwise have to guess at — how the insulation is built up, exactly where the steel sits and how it bears, how the drainage runs, how fire and escape are handled — and that clarity reduces both errors and disputes during the build.
There are two routes to Building Control sign-off in England and Wales: a full plans application, where the drawings are checked and approved before work starts, or a building notice route used mainly for smaller, simpler jobs where the work is inspected as it proceeds. The full-plans route, supported by a proper drawing set, gives more certainty because problems are caught on paper rather than mid-build. Whichever route applies, the technical drawings need to align with the structural engineer's calculations and with the design that gained planning permission, so coordination matters. This is the value an architect or technologist adds at this stage — not just producing drawings, but producing a coherent set that the builder can price accurately and build from confidently. Skimping here to save a modest fee often costs more later in site queries, variations and remedial work, which is why the building-regs drawings repay being done properly.
Frequently asked questions
Are building-regs drawings the same as planning drawings?
No. Planning drawings prove your proposal is acceptable in principle and are assessed by the council's planning team. Building-regulations drawings are a separate, more detailed technical set showing how the work is built safely, and they're checked by Building Control. Each is a separate stage and fee.
Do I need a structural engineer as well as the architect?
Usually yes, if your project involves beams, removing walls or other structural changes. The architect produces the building-regs drawings, but the structural calculations behind any beam or structural element are normally a separate structural-engineer appointment and fee.
Does the fee include the Building Control charge?
No. The architect's fee covers preparing the drawings. The Building Control application and inspection fee is paid separately to the local council's Building Control or an approved inspector, and VAT on the architect's fee is normally extra too.
Sources & further reading
- GOV.UK — building regulations approval
- HomeOwners Alliance — architects guide
- Checkatrade — architect fees guide
Figures on this page are typical UK ranges drawn from published sources and depend on your specific project. They are guidance, not a quotation.