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Extension Plans

Extension Plans are your local London Architects offering a fast, affordable, one-stop solution for all your planning permission and building regulation needs.

Expert Residential Design

Call for a free quotation on 020 3633 1082
  • ARB Registered Architect
  • Prices start from £995 plus VAT
  • 12 Working Days Turnaround
  • 020 3633 1082
  • info@extensionplansuk.co.uk

We are with you all the way

Welcome to Extension Plans, your trusted team of architects in London, specialising in affordable, high-quality residential designs. From rear extensions  and side extensions to loft conversions and full-home transformations, we’re here to turn your vision into reality with a personalised, London-focused approach.

Experience a new standard of architectural design with our all-inclusive, cost-effective architectural service. We combine attention to detail with a commitment to quality, ensuring every space we create aligns with your vision and lifestyle.

Your dream home journey begins here !

Why We're Your Ideal Partner

ARB Architects

Talented architects with proven track records drive our projects.

Cost-Effective

We are currently offering a 100% money back guarantee if planning is refused

All Inclusive

Don't worry about outsourcing any aspect of your project with our comprehensive service

Quick Turnaround

Progress to the construction stage with minimum delay with our streamlined service.

Example project showing design quality

100% Money Back Guarantee

We’re proud to offer a 100% Money Back Guarantee on our drawings. If your planning application is refused, we’ll refund the cost of the drawings in full. Your success is our top priority.

*Guarantee is subject to certain conditions.

100% Refund Guarantee

Book A Free Consultation With One Of Our Experts

Our Services

Rear extension Planning permission architects building regulations architects

Architectural Drawings

Our experienced team has worked on every type of residential alteration throughout the years and we are excited to share our knowledge with our customers!

side extension and rear extension completed with planning permission approval

Building Regulations

Our team excels at creating precise, compliant drawings, ensuring alignment with safety, thermal, and structural requirements.

Dual pitched rear extension design with building regulations

Structural Calculations

Once our architects have crafted your vision into architectural drawings, our engineer steps in to produce precise structural calculations.

interior renovation project completed with building regulations and building control approval

Party Wall Services

As part of our comprehensive architectural services, we include the preparation of the party wall notices within our process.

Here To Help With All Your Residential Improvement Requirements

Extension Projects

We specialise in expert design for home extensions, creating bespoke spaces that enhance your lifestyle and increase the value of your property.
loft conversion architect planning permission architects building regulations architect

Loft Conversion Projects

At Extension Plans, our expert loft conversion designs demonstrate how you can maximise your home's potential by transforming unused attic space into functional and stylish living areas.

Outbuilding Projects

As well as extensions and loft conversion we also design outbuildings that are both functional and beautifully tailored to your needs.

We have completed work across the whole of London. Check out our completed project locations

Our Services

We pride ourselves on delivering an all-inclusive architectural service to our clients, with a vast amount of experience, with rear extensions, loft conversions, and outbuildings. By working with us, you eliminate the need to outsource various components of your project, streamlining the entire architectural process under one roof.

Site Survey

Our dedicated surveyor will visit your property to gather all of the necessary measurements and essential site information.

Architectural Drawings

Upon appointing our services, you'll be paired with the most suitable member of our design team, ensuring a tailored approach to your project.

Planning Submission

We take the hassle out of the approval process by handling the submission of all planning applications to the local council.

Building Regulation Drawings

Our designers create detailed building regulation drawings with precision, ensuring full compliance with standards and reducing potential construction issues

Building Control Submission

Our team is committed to providing a hassle-free experience, and that includes submitting the building control application on your behalf. Trust us to handle the paperwork and navigate through the process

Structural Engineering Service

We partner with expert engineers to provide precise structural calculations, ensuring the safety and stability of your construction.

Finding a Builder

Once the paperwork is complete, we arrange build quotes from vetted, quality-checked builders, ensuring your project is in skilled hands for a smooth construction process.

3D Visuals

Enhance your design experience with realistic 3D drawings from our dedicated team, offering a detailed preview of your finished space.

Party Wall Notices

We collaborate with a party wall surveyor who handles the serving of party wall notices on your behalf, ensuring the process is managed as efficiently as possible.

How It Works

Our streamlined process ensures you’re matched with the ideal member of our design team, who will guide you through every step, from concept to completion

Step 1
Step 1

Free Consultation Call

Call our office anytime or schedule a free consultation with our company director. We’ll discuss your ideas, provide design guidance, and walk you through the entire process.
Step 2
Step 2

Site Survey

Our dedicated site surveyor will visit your property and gather all the measurements and required site information 
Step 3
Step 3

Design Meeting

With thousands of completed projects, we have plenty of ideas to share! You’ll collaborate directly with the designer best suited to your project, who will bring your ideas to life while providing suggestions and creative solutions to ensure the design is the best it can be
Step 4
Step 4

Planning Approval

Our administration department will take care of preparing and submitting all design applications to your local council. We also act as the agent during the application process to ensure approval is received as quicky as possible
Step 5
Step 5

Building Regulations

We will then produce detailed building regulation drawings and organise the structural calculations, ensuring your builders can begin construction work with minimal delay
Step 6
Architects, loft conversion, side extension planning permission
Step 6

Builder Connect

Once we have all your documentation in place place, we’ll connect you with a trusted builder we recommend.

Book A Free Consultation With One Of Our Experts

Check Out a Couple Of Our Recent Projects

We’ve worked on every type of residential property, from period homes to new builds, bringing a wealth of experience to each project. Take a look at some of our recent work below to see what we can do.

double storey extension with building regulations

Part double part single storey rear extension in HA5

crittall doors extension, kitchen extension design by architects

Single storey rear extension with a dual-pitched roof and crittall doors in W5

rear extension interior design, kitchen extension

Single storey rear extension with open plan living space in TW7

Spacious single storey rear extension with open plan kitchen/diner in DA5

Single storey rear extension with large kitchen/diner in SE25

Kitchen design in extension space architects

Wraparound Extension with new kitchen and living space in BR5

What Makes Us Stand Out From The Crowd

Unlimited Support

Call our office at any time to discuss your project. We are also on hand for questions from your builders until construction has been completed.

We handle everything

We have an experienced administration team to submit and handle your applications so you don't have to.

Immediate Start

We are available to start work on your project within a couple of days!

Rear extension with planning permission approved, created by architects

Dedicated Designers

You will be working directly with the member of our team that is best suited to your project.

Detailed Drawings

Our drawings are created with the best architectural software available ensuring your plans are created to the highest standard.

Fixed Prices

We offer fixed, competitive prices so you can budget accurately for your build.

What Our Customers Say

We have over 600, five star reviews across our online platforms. Check out our Trustpilot reviews here 

Unlock the potential of your property

Schedule a free consultation! We would love to offer free advice, discuss your design ideas or get things moving with your project
contact us

How Do We Differ From Other Architects?

  • Features

  • Traditional Architects 

  • Online Competitors 

  • Fixed Price

  • Immediate Start

  • Planning Design Drawings 

  • Flexible project timeline

  • Qualified Architects 

  • Submission of all relevant applications

  • Building Regulation Drawings 

  • Advance Drawing Technology

  • Flexible Remote Meetings 

    • FAQs

    Our design process begins with an initial consultation with your dedicated designer. We will discuss your vision, requirements and we will provide ideas for your design based on previously completed projects. From there, we move through conceptual design providing a first draft plan for your consideration. Following this we can revise the plans in any way you like to ensure you a completely happy with the design. 

    The timescale of a project differs, depending on the proposal. We can visit your property within a couple of days and have the first draft plans with you in roughly 14 days. 

    In some cases, building work can begin within a couple of weeks. In others, the timescale can be up to 4 months, depending on your project’s requirements. 

    Yes, we work with a dedicated team of experienced engineers who take care of all structural calculations and beam specifications. This allows us to manage every technical detail, so you won’t need to outsource this essential service.

    Yes, we employ fully qualified architects within our design team to ensure our plans are created to the highest possible standard. 

    With over 7 years of collaboration with every  council in London, we’ve built a trusted relationship with their planning officers and are well-versed in their guidelines. This expertise ensures a smooth and efficient planning process for your project.

    Yes, we organise all necessary applications on our customer’s behalf. We will submit the required application and act as the agent throughout the process to ensure approval is received as swiftly as possible

    Yes, we create our plans with industry-leading software and are able to create 3D images to allow you to accurately visualise your design. 

    In most cases, we have trusted building contractors that we have worked with in your area, in the past and we would be happy to organise build quotations for you to consider 

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