Home Extension
Step into your new home in virtual reality before we lay a single brick. We deliver a complete, end-to-end service for stunning, high-value home extensions.
Imagine walking through your new, spacious kitchen, stepping into a sun-drenched living area, and assessing every detail with complete clarity… all months before construction begins. At Reltic BIM, this isn’t a future gimmick; it’s our standard. We are a premier Design & Build company in London, where an advanced BIM (Building Information Modelling) design process is fully integrated with our own in-house, certified construction teams.
We specialise in bespoke house extensions across London, offering a single, seamless, and fully managed process. With us, you don’t just see plans; you experience your future home, ensuring the final result is an intelligent, high-value investment that perfectly enhances your property and lifestyle.
Intelligent Home Extension Design
Whether you’re looking for an all-new house extension in North London, a two-storey rear extension in South London, a side return in West London, a standard extension in East London,Reltic BIM is here to guide you at every step of the way, utilising the very latest technology.
Our foundation is Building Information Modelling (BIM). Instead of traditional plans, we create the precise, intelligent 3D models that make these benefits possible. We ensure every project is fully compliant with building regulations and local council planning requirements.
Throughout the project, your dedicated project manager will be on hand to answer any questions you may have. Furthermore, our fixed prices and timescales mean you know exactly what you will pay and for how long our experts will be on site. Regular meetings and access to the digital model ensure you have peace of mind, always staying up-to-date with the progress of your project.
Our intelligent BIM process delivers complete clarity and control over your project:
- See your finished space in virtual 3D.
- Prevent costly errors before we build.
- Optimise costs and reduce material waste.
- Certainty on your final price and time.
Why a Home Extension is London's Smartest Property Investment
Navigating the London property ladder is a costly and stressful endeavour. Instead of facing the market, unlock the hidden potential of the home you already love. A professionally managed extension is an intelligent financial decision that allows you to:
Before you spend tens of thousands of pounds on Stamp Duty and legal fees just to move, consider this: the same funds can be invested directly into your current home. This isn't a sunk cost – it's an investment that builds the value of your asset.
Modern life demands more from our homes. We create the open-plan living spaces ideal for family life, quiet, dedicated home offices for productivity, and additional bedrooms with en-suites to enhance comfort for everyone.
In London’s competitive market, well-designed space is the ultimate premium. A high-quality extension is one of the most reliable ways to increase your home's market value, often by more than the cost of the project itself.
Often, the problem isn't just a lack of space, but a poor layout and a lack of natural light. An extension is the perfect opportunity to reconfigure your home’s floor plan, brighten dark interiors, and create a seamless indoor-outdoor connection to your garden.
Designed for London homes - built around you.
We design and build five core types of home extensions to suit every layout, lifestyle and budget – whether you’re looking to open up your ground floor, add an extra level, or completely transform your space.
Rear
Extensions
Perfect for opening up your living space and connecting your home to the garden. Ideal for kitchen extensions or open-plan family rooms with added light and flow.
Side Return Extensions
Use alleyways or side space to expand your ground floor. Great for terraced and semi-detached homes adding space without losing garden area.
Wraparound Extensions
Combine rear and side extensions to dramatically increase your home’s footprint. Adds space, flexibility, and design freedom for open-plan living.
Double Storey Extensions
Expand your living area both up and out. A great option when you need extra bedrooms, a home office, or bathrooms while maintaining garden space.
Full Width
Extensions
Stretch across the entire back of your property. Maximise internal layout, boost natural light, and create a sleek, modern space for everyday family living.
Find Out How Much Value You Could Add to Your Home.
Your Guarantee of Value, Safety, and Security
Our advanced BIM technology is your insurance policy against the most common construction problems. It is a tool for optimisation, not for adding cost.
Our immersive 3D tours empower you to make key design decisions with absolute confidence, eliminating the risk of expensive changes during the construction phase.
Our detailed BIM process allows us to provide a fixed-price quote after the design is finalised. This ensures complete financial clarity and protects you from hidden costs.
As your sole point of contact, we take full responsibility for every single stage, ensuring a smooth, blame-free, and efficient project.
The precision of our 3D models allows us to detect potential clashes before they happen and order materials with near-perfect accuracy. This means less waste and ensures every pound of your investment is maximised.
The Integrated Design & Build Process: From Concept to Completion
We have refined our entire workflow into six clear, client-focused stages where technology and craftsmanship work in perfect harmony.
Step 1
Consultation & Feasibility Study
We start with a conversation to understand your vision, needs, and budget. We assess your property and local council’s planning policies to advise on the most effective route to permission.
Step 2
Measured Survey & 3D BIM Setup
Our team conducts a precise digital survey of your home, using the data to build an accurate 3D model in Autodesk Revit. This becomes the single source of truth for the entire project.
Step 3
3D Concept Walkthrough
Our team conducts a precise digital survey of your home, using the data to build an accurate 3D model in Autodesk Revit. This becomes the single source of truth for the entire project.
Step 4
Planning & Technical Drawings
We prepare and manage the planning application. In parallel, our in-house architects and engineers create the detailed technical drawings for Building Control approval.
Step 5
Final Plan & Fixed Quote
With all permissions fully secured, you receive a full, fixed-price quote and contract for the entire build. This provides absolute transparency and is your guarantee against budget creep.
Step 6
Turnkey Construction
Our certified in-house team manages the entire build, from procurement to final finishes. Track progress 24/7 on your Autodesk Construction Cloud portal for complete, stress-free oversight.
FAQs About Home Extensions
Have questions about how a home extension project works from start to finish? We believe in providing clear, straightforward answers. Find our responses to the most common queries below.
Why is the Design & Build model better for my extension?
Because it is a more efficient, accountable, and less stressful way to build. With one company responsible for both design and construction, you have a single point of contact and a unified team working towards the same goal. This eliminates the classic conflicts between architect and builder, saving you time, money, and hassle.
How much does a house extension cost in London?
We understand that budget uncertainty is a major concern. Our entire process is designed to eliminate it. While construction costs vary based on size and specification, our process is built to provide you with maximum value and control. After the design is complete, we provide a detailed, fixed-price quote. This protects you from unforeseen expenses and allows you to proceed with your project with complete financial confidence.
What’s the difference between Planning Permission and Building Regulations?
They are two separate legal requirements. In simple terms: Planning Permission deals with IF you can build. It assesses the appearance, size, and impact of your project on the surrounding area and your neighbours. Building Regulations deal with HOW you must build. They set the minimum technical and safety standards for structural stability, thermal insulation, fire safety, ventilation, and more. Almost every extension project requires Building Regulations approval, even if it doesn’t need Planning Permission. Our Design & Build service manages both processes comprehensively for you.
Can I live in the house during the construction work?
In most cases, yes. We meticulously plan our work to minimise disruption to your daily life. The key is to isolate the construction zone from the rest of your home using temporary, dust-proof partitions and protective coverings. If we are working on your kitchen, we often set up temporary kitchen facilities in another room. Naturally, a degree of noise and disruption is unavoidable, but our teams make every effort to respect your privacy and comfort throughout the build.
How long does the entire process take, from the first conversation to completion?
Every project is unique, but a typical timeline for a standard home extension in London is as follows:
- Design & Planning Phase: On average, this takes 3-5 months. This includes our initial consultations, the survey, the design process, and then waiting for the council’s decision (typically 8-10 weeks for a Planning Permission application).
- Construction Phase: On average, this takes 4-6 months for a standard single-storey extension. The entire end-to-end process usually takes between 7 and 12 months, depending on the project’s scale, complexity, and the local council’s processing times.
My house is in a Conservation Area. Is that a problem?
It is absolutely not a problem, but it does require specialist expertise. Properties in Conservation Areas are subject to much stricter planning controls, and Permitted Development Rights are heavily restricted or removed entirely. This means a Full Planning Application is always necessary, where it’s crucial to demonstrate that the design respects and enhances the historical character of the area. We have extensive experience designing for these sensitive locations and know how to use appropriate materials and architectural forms to achieve planning consent.
Do I need to hire my own Structural Engineer?
No, you don’t. As part of our fully managed Design & Build service, we coordinate and manage all necessary consultants on your behalf. This includes certified structural engineers, Building Control inspectors, and any other specialists required for your project. This is a core part of our promise to deliver a seamless, hassle-free experience for our clients.
What guarantees and insurance do you provide?
The security of your investment is paramount. During the construction phase, your project is protected by our comprehensive Public Liability Insurance and Contractor’s All-Risk Insurance. Upon completion, we provide our own workmanship guarantee, which is clearly defined in our building contract. This gives you peace of mind both during and long after the project is finished.
What happens if unforeseen issues arise during the build?
Transparency is key. While our detailed BIM design process minimises the risk of surprises, should something unexpected be discovered on-site (e.g., hidden pipework or foundation issues), we communicate with you immediately. Using our online platform (Autodesk Construction Cloud), we present the issue, our proposed solutions, and any potential cost or time implications. No additional work is ever undertaken without your full knowledge and formal approval.
