Clear, fixed-fee pricing for architectural drawings, planning applications and structural engineering across London. No hidden costs, no hourly rates.
Select the service that matches your project to see detailed pricing, inclusions and FAQs.
Rear extensions, side returns, kitchen extensions and wraparound single storey additions.
Plans from £900 + VAT
View pricingTwo-storey extensions to add significant space across both ground and first floors.
Plans from £1,100 + VAT
View pricingDormer, hip-to-gable, mansard and Velux loft conversions to unlock extra living space.
Plans from £900 + VAT
View pricingConverting houses into self-contained flats with planning permission and building control.
Plans from £1,500 + VAT
View pricingCommercial to residential, retail to office and other use class change applications.
Plans from £900 + VAT
View pricingAn at-a-glance view of starting prices across all our services.
| Service | Planning | Building Regs | Structural | |
|---|---|---|---|---|
| Single Storey Extension | £900+ | £500+ | £500+ | Details → |
| Double Storey Extension | £1,100+ | £500+ | £800+ | Details → |
| Loft Conversion | £900+ | £500+ | £500+ | Details → |
| Flat Conversion | £1,500+ | £1,000+ | £500+ | Details → |
| Change of Use | £900+ | Quote | Quote | Details → |
All prices exclude VAT. Free consultation available for all services.
Accreditations & Education
Our team’s background combines architectural design, structural engineering and construction delivery.
Institution of Civil Engineers
The Institution of Structural Engineers
Academic excellence in the built environment
Academic excellence in design & innovation
Academic excellence in architecture & engineering
Institution of Civil Engineers
The Institution of Structural Engineers
Academic excellence in the built environment
Academic excellence in design & innovation
Academic excellence in architecture & engineering
From your first enquiry to submission and support, our process is designed to keep your project clear, organised and moving forward.
An appointed surveyor will carry out a full measured survey of your property, noting down all your desired requirements for your proposal.
Your project is allocated to one of our architectural designers who will design it from the ground up, taking into account all your needs.
Your first draft is typically ready in 7 working days, and within 10 at the latest. Review the designs, send us any changes, and we’ll finalise your drawings for submission.
Your plans will be submitted strategically for swift council approval. Expect a decision in 6–8 weeks. We handle any required changes for free.
Once plans are approved, our Structural Engineers and Architects will manage the Structural Design and Building Regulations compliance. You can also get construction quotes from us to compare.
If you decide to build with us, we arrange a detailed consultation to finalise your requirements and ensure everything aligns perfectly with your vision.
Ready to start your project?
Get a Free ConsultationWhy Choose Us
From planning strategy to technical design and construction support, we combine practical experience with clear communication at every stage.
Our team brings extensive experience working with local authorities across London and beyond. From Lambeth to Hillingdon, we understand how different councils approach planning decisions.
We moved beyond 2D drawings years ago. Our 3D designs let you see the before and after of your property long before construction begins, so there are no surprises.
A dedicated project manager keeps your project on track with clear communication at every milestone. We maintain one of the fastest turnaround times in the industry.
Our guidance goes well beyond planning and architecture. We support you through the entire journey, from initial concept through to construction and completion.
Structural engineers, architectural designers and construction managers work side by side from day one, keeping your project coordinated, efficient and on brief.
With thousands of completed projects across our team, we bring deep expertise in residential design, structural engineering and the UK planning system.
Common questions about our pricing, fees and what is included.
Book a free consultation and receive a fixed-fee quote for your project. No obligation, no pressure.
Share your project details and our team will review the scope, provide clear guidance, and come back with practical next steps — no obligation, just honest advice.
Extension, loft, new build — share your ideas using the form
Our architects assess your property and project requirements
Get a fixed-fee quote and a practical plan to move forward
Fill in what you can — we'll follow up with anything else we need.
Speak with Salstan about your planning, architecture, structural engineering or building regulations project. We’ll help you understand the next steps and provide a clear, no-obligation quote.
We are a full-service, turnkey firm specialising in Architecture, Planning Permission, Building Regulations, Structural Design, Civil Engineering and Construction.
