At Double Storey Extensions, we create large-scale home additions that expand both ground and first-floor living space for homeowners across the UK.

Whether you’re adding extra bedrooms, extending your kitchen, or creating multi-level open-plan layouts, we handle everything from design and planning through to construction and finishing. Our double storey extensions are designed for strength, efficiency, and seamless integration with your existing home architecture.

How Much Does a Double Storey Extension Cost?

The cost of a double storey extension ranges from £2,400 to £3,200 per square metre, depending on design complexity, materials, and specification.

Pricing is influenced by the size of the extension, the structural work required, finishes, glazing, and the inclusion of features such as en-suite bathrooms or balconies. Adding extra storeys generally increases overall value while maintaining cost efficiency compared to separate builds.

Contact Double Storey Extensions to get customised prices for your two-storey home extension.

Which Double Storey Extension Designs Are Most Common?

Homeowners can choose from several popular double storey extension layouts, including:

• Rear double storey extensions – Expanding at the back of the house to add downstairs living space and upstairs bedrooms.
• Side double storey extensions – Utilising unused side land on detached or semi-detached homes for significant internal gain.
• Wraparound double storey extensions – Combining side and rear extensions to create full-width, two-level expansions.
• Over-garage extensions – Building above existing garages to add an extra bedroom, bathroom, or study.
• Front-facing extensions – Extending toward the front façade for additional entrance space or bay-style rooms, where permitted.

Is Planning Permission Required for a Double Storey Extension?

Planning permission for double storey extensions is often required, especially when the structure extends beyond permitted development limits.

We handle all planning submissions, including site drawings, elevations, and design statements, ensuring your extension complies with local authority regulations and neighbour consultation rules. Properties in conservation areas or near boundaries may need additional assessments, which we manage as part of our full-service process.

What Materials and Finishes Are Ideal for Double Storey Extensions?

The choice of materials plays a key role in achieving a cohesive and durable finish, including:

• Brickwork or stone – Matching existing materials for visual continuity and strength.
• Rendered exteriors – Smooth finishes that complement both modern and traditional homes.
• Composite cladding – Weather-resistant materials offering a sleek, contemporary aesthetic.
• Aluminium or timber glazing systems – Used for large openings, sliding doors, or Juliet balconies.
• Roofing materials – Tiles, slates, or flat roofing membranes to align with the original property.
• Internal finishes – High-quality flooring, lighting, and plasterwork to unify both levels of the extension.

How Long Does It Take to Complete a Double Storey Extension?

The average timeframe for designing and building a double storey extension ranges between 20 and 32 weeks.

This includes 3–5 weeks for design and approvals, up to 8–10 weeks for planning decisions, and approximately 12–16 weeks for construction. Timelines can vary based on weather, materials, and any required structural modifications, but we maintain clear project scheduling throughout.

How Can a Double Storey Extension Transform Your Home?

A double storey extension can redefine your home’s layout, adding both functional and aesthetic value.

By extending across two floors, you can create larger living areas downstairs and increase bedroom or bathroom capacity upstairs, achieving a balanced and efficient space without relocating.

Do Builders Provide Full Design-and-Build Solutions for Double Storey Extensions?

Many local contractors offer partial construction services, but our double storey extensions team provides full design-and-build packages.

We manage every stage—from architectural drawings and planning applications to engineering coordination and build delivery—ensuring efficiency, transparency, and quality control throughout the project.

Contact Double Storey Extensions for a consultation on designing and building your next multi-level home addition.

Are Double Storey Extensions a Good Investment for Homeowners?

A well-designed double storey extension can increase property value by 20–25%, providing strong returns for growing families and long-term homeowners.

We focus on smart space planning, structural integrity, and architectural harmony to ensure your investment delivers both financial and lifestyle benefits.

Find More Info

Make sure you contact us today for a number of great double storey extensions services.

For more information on Double Storey Extensions, fill in the contact form below to receive a free quote today.