Your Double-Storey Extension
A double-storey extension adds meaningful space upstairs and downstairs. Whether you need more bedrooms, a spacious open-plan kitchen, this type of extension gives you long-term flexibility without the cost and stress of moving.
Twice the Space. Twice the Value. More Possibilities.
Double-storey extensions typically provide the highest return on value per square metre and can add 20–30% to your home’s value
Because the second storey sits on the same foundations and roof structure as the ground floor, a double-storey extension gives you twice the space for a fraction more cost compared to a single-storey build.
Why a Double-Storey Extension?
A double-storey extension extends both your ground floor and first floor, giving you extra space where it matters most. It’s ideal for homeowners who love their location but need their home to grow with them.
Perfect for:
Open-plan kitchen and dining spaces
Additional bedrooms or a master suite
Extra bathrooms or an ensuite
Dedicated office space, guest room or playroom
Looking for something bespoke? Tell us what you need and we can help you design it!
Bespoke or tailored solutions to your needs
Every home is different and so is every extension we design.
We take time to understand your layout, budget and priorities before presenting ideas that suit your lifestyle.
Whether you want:
A sleek, contemporary glass extension
A warm brick-built extension that blends with tradition
A light-filled kitchen extension with sliding doors
A practical side return extension
We balance design, functionality and cost at every stage.
Planning Permission & Regulations
Most double-storey extensions require planning permission, but we make the process simple.
We handle:
Feasibility checks
All architectural drawings
Planning submissions
Council communication
Revisions if needed
If your home qualifies for Permitted Development Rights, We’ll guide you through that route too.
Single-Storey vs Double-Storey Extensions
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Single-Storey
A single-storey extension is ideal if you’re looking to expand your kitchen, create a brighter dining space or open up your ground floor to connect more naturally with your garden. It’s a cost-effective way to improve everyday living, bringing in more light and giving you the flexibility to redesign the space your family uses most.
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Double-Storey
A double-storey extension goes a step further, adding valuable space upstairs as well as downstairs. It’s the right choice when you need extra bedrooms, a master suite, additional bathrooms or room for a growing family. Because the upper level builds on the same foundations, you gain twice the space for only a fraction more cost than a single-storey build.
Our Architectural & Build Process
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1. Consultation
We start with a relaxed conversation to understand your goals, budget, and how you want to live in your home.
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2. Site Survey & Existing Drawings
Accurate measurements and existing plans ensure every decision is informed and technically sound.
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3. Design & Proposed Plans
We explore layouts, ideas, and design options, refining everything with you before finalising drawings.
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4. Planning & Approvals
If required, we manage planning applications and liaise with your local authority
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5. Building Regulations & Technical Drawings
We prepare the detailed drawings needed to ensure your project is safe, compliant, and ready to build.
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6. Construction
Your plans are brought to life with care, clear communication, and attention to detail throughout.
Are We the Right Fit for Your Renovation?
We work best with homeowners who want a thoughtful, well-managed renovation. Do you value clear communication, quality design, and a personal, family-run approach that puts you and your ideas and the centre of every decision?
If you're looking for a complete home transformation and want a team who listens closely and guides you through every stage with transparency, we’re a great fit.
Let’s create a double-storey extension that gives your family more room, comfort and long-term value.
Ready to transform your home?
FAQ’s
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You can build a double-storey extension under permitted development rights only if it’s a rear extension and meets strict size limits:
Location: Rear of the house only; not side or front.
Depth: Maximum 3m for terraced/semi-detached, up to 4m for detached.
Height: Cannot exceed the height of the original house's eaves or roof ridge.
Boundary Rule: If within 2m of a boundary, eaves height must be no more than 3m.
Proportions: Width must be less than 50% of the original house's width; total extension area <50% of land around the original house.
Restrictions: No balconies, terraces, verandas, or roof alterations (like chimneys).
The above does not apply if you are in a conservation area, AONB or the property is a new build from prior approval!
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As a rough guide follow the £/sq foot in your area times the square footage you want to add, plus maybe a premium (5-25%) if your house ends up being unique on the street!
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This all very much depends on size, location and complexity of the project! Generally this can be anywhere between 14-20+ weeks or more for construction, plus any time for design and planning approval.
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Surprisingly, the answer is often yes! It all depends on the scale of work, but some of our clients have remained at the property even during large scale extensions. That’s not to say that life doesn’t get a whole lot messier, busier and noisier!