How Much Do Architectural Drawings Cost in London? (2026)
Architectural drawing costs in London vary from £800 for basic planning drawings to £8,000+ for a full package from a traditional practice. This guide breaks down every drawing type, what drives the price, and which fee model gives you the best value.
TL;DR - The Quick Answer
For a standard London rear extension or loft conversion in 2026, expect to pay £1,295–£1,795 for planning drawings plus application (Mayfair Studio's fixed-fee range), and a further £1,500–£2,500 for building regulations drawings. Structural engineering adds £600–£1,500. Total design cost before construction: typically £3,500–£6,000 from a fixed-fee service, versus £8,000–£18,000 from a traditional practice charging a percentage of build cost.
Cost Breakdown by Drawing Type
A home extension project requires several distinct types of drawings, each serving a different purpose and often commissioned at different project stages.
| Drawing Type | Purpose | Typical Cost (London) | When Needed |
|---|---|---|---|
| Planning drawings | Planning permission application | £1,295–£3,000 | Before planning submission |
| Building regs drawings | Building control approval | £1,500–£4,000 | After planning granted |
| Structural drawings | Structural calculations for beams, foundations | £600–£1,500 | With building regs |
| Concept drawings | Design exploration (optional) | £500–£1,500 | Before planning drawings |
| Tender package | For builders to quote from | £800–£2,000 | Before builder tender |
Prices are for a standard single-storey rear extension in London. Two-storey or complex projects cost more.
| Drawing Type | Purpose | Typical Cost | When Needed |
|---|---|---|---|
| Planning drawings | Planning permission application | £1,295–£3,000 | Before planning submission |
| Building regs drawings | Building control approval | £1,500–£4,000 | After planning granted |
| Structural drawings | Beam and foundation calculations | £600–£1,500 | With building regs |
| Concept drawings | Design exploration (optional) | £500–£1,500 | Before planning drawings |
| Tender package | For builders to quote from | £800–£2,000 | Before builder tender |
Source: Mayfair Studio project data • Data as of 2026
What Affects the Cost of Architectural Drawings
Project size and complexity
A 3m single-storey rear extension with a flat roof requires fewer drawings than a two-storey side and rear wrap-around. Complexity - curved walls, structural complications, unusual sites - increases both drawing time and costs.
Conservation area or listed building
Conservation area extensions require additional supporting documents: heritage statements, materials schedules, sometimes design review responses. Listed building applications require significantly more work. Add 25–50% to standard drawing costs.
Number of revisions
Most fixed-fee services include one or two revision rounds. Additional revisions are charged at £150–£500 per round depending on the extent of changes. Agreeing the design before drawings start reduces revision costs significantly.
Level of service
Drawings-only services are cheapest. Adding planning application management, council correspondence, and post-approval support adds cost but saves time. Full-service packages from Mayfair Studio include all of this at the fixed fee.
Architect vs architectural technician
ARB-registered architects generally charge more than architectural technicians. For planning drawings on a standard extension, the quality and planning outcome are typically equivalent. The title difference rarely matters for standard residential projects.
Fixed Fee vs Hourly: Which Is Cheaper and When
For standard extensions, a fixed fee is almost always cheaper than hourly billing. Here is why:
| Fixed Fee | Hourly Rate | % of Build | |
|---|---|---|---|
| Typical cost (rear extension) | £1,295–£1,795 | £3,000–£6,000 | £8,000–£15,000 |
| Cost certainty | High | Low | Medium |
| Risk of overrun | None | High | Rises with build cost |
| Best for | Standard extensions | Short ad-hoc tasks | Complex full-service projects |
Hourly rates (£80–£200/hour in London) work out cheaper only for very short, tightly scoped tasks - a planning query, a single drawing revision. For a full planning drawings package, fixed fees win on both cost and predictability.
What Mayfair Studio Charges and What You Get
Mayfair Studio offers fixed-fee architectural services for London residential extensions:
Planning Package
From £1,295For rear extensions, loft conversions, side returns, kitchen extensions
- Permitted development check
- Site survey and measured drawings
- Planning drawings (site plan, floor plans, elevations)
- Design and access statement
- Planning application submission
- Council correspondence
- Two revision rounds
Full Design Package
From £1,795For larger or more complex projects including two-storey extensions
- Everything in Planning Package
- Additional design development
- More complex site constraints
- Extended revision allowance
Architectural drawing costs in London in 2026: planning drawings cost £1,295–£3,000, building regulations drawings £1,500–£4,000, and structural drawings £600–£1,500. Total design cost is typically £3,500–£6,000 from a fixed-fee service versus £8,000–£18,000 from a traditional practice charging a percentage of build cost.
Frequently Asked Questions
Can I get just planning drawings without building regulations drawings?
Yes. Planning drawings and building regulations drawings are separate services. Planning drawings are used to obtain planning permission from the council. Building regulations drawings are used to get building control approval before construction begins. You will need both for most extensions - but you can appoint an architect for planning first, then commission building regulations drawings once permission is granted. This is the standard sequence.
How long does it take to get architectural drawings for an extension?
Initial planning drawings typically take 2–4 weeks from your site survey, depending on the designer's workload and the complexity of your project. Building regulations drawings take a further 3–6 weeks after planning is granted. The full timeline from appointing an architect to having building regulations approved is typically 4–6 months - including the 8-week council planning decision period.
What is the difference between planning drawings and building regulations drawings?
Planning drawings show what you want to build - the layout, size, and appearance - and are used to obtain planning permission. They are drawn to scales of 1:50 or 1:100 and focus on the visual and spatial aspects. Building regulations drawings are technical construction documents showing how the building will be built: structural details, insulation, drainage, fire safety, ventilation, and energy performance. They are used by building control and your builder.
Are architectural drawings cheaper outside London?
Yes. Architectural drawing costs are roughly 20–35% lower in other UK cities compared to London. London premiums reflect higher overheads, longer planning processes, and more complex site constraints. For a standard rear extension, expect to pay £1,000–£1,500 more for drawings in London than in Birmingham or Manchester.
What does a site survey involve and how much does it cost?
A measured survey involves an architect or surveyor visiting your property and taking precise measurements of all rooms and elevations that will be affected by the extension. This produces the existing floor plans and elevations used as the baseline for designing the extension. Most fixed-fee architectural services include the site survey in their fee. If charged separately, expect to pay £200–£500 for a standard residential survey.
Do I need a structural engineer as well as an architect?
Yes, for most extensions. Your architect produces the planning drawings and building regulations drawings, but the structural elements - RSJ beams, foundations, lintels, load-bearing wall removals - require separate structural calculations from a qualified structural engineer. Structural engineering fees for a standard extension typically run £600–£1,500. This is separate from architect fees.
Architectural drawings for a home extension in London cost £750–£4,000. Drawings-only services start at £750–£1,500 but don't include structural calculations or planning application - add £2,000–£5,000 for those separately. An all-in fixed-fee service from Mayfair Studio costs £1,295 including planning drawings, structural calculations, and planning application - typically the best value option for standard London extensions.
Frequently Asked Questions
How much do architectural drawings cost for a home extension in London?
Architectural drawings for a home extension in London cost £750–£4,000+. Drawings-only services: £750–£1,500 (structural and planning extra). Full service including structural calculations and planning application: £1,295 (Mayfair Studio fixed fee) to £3,500+ (traditional architects at 8–15% of build cost). For a £55,000 extension: Mayfair Studio £1,295 vs traditional architect £4,400–£8,250.
Do I need an architect for planning permission for a home extension?
You don't legally need an architect, but you do need professionally prepared planning drawings that meet Local Authority standards. These must show existing and proposed floor plans, elevations, and site location plans to scale. Many homeowners use specialist services like Mayfair Studio (from £1,295) which prepare drawings and handle the full planning application. DIY drawings are almost always rejected - councils require drawings to specific technical standards.
What drawings do I need to submit for planning permission in London?
A planning application for a home extension in London requires: location plan (1:1250 scale), site plan (1:500 scale), existing floor plans (1:100 scale), proposed floor plans (1:100 scale), existing elevations (1:100 scale), proposed elevations (1:100 scale). Some applications also require a design and access statement. Structural drawings are not required for planning but are essential for building regulations approval before construction starts.
How long do architectural drawings take for a home extension?
Architectural drawings for a home extension typically take 3–6 weeks from site survey to planning submission. Mayfair Studio's process: initial AI consultation (immediate), site survey (1–2 weeks), draft drawings (2–3 weeks), revisions (1 week), planning submission. After submission, planning determination takes 8–12 weeks. Total from starting with an architect to planning decision: 3–4 months.