Double Storey Extensions Across London

For over 22 years, Foundation and Finishing has been delivering Double Storey Extensions across Greater London. We add space on two levels at once, creating larger ground-floor areas and extra bedrooms or bathrooms above.

London's Most Trusted Construction Partner

20+ Years Delivering Excellence

100+ London Projects Completed

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Based on 56 Reviews
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Based on 82 Reviews
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Based on 108 Reviews

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Our Services

Professional Building Services in Double Storey Extensions

For over 22 years, Foundation and Finishing has been delivering exceptional Double Storey Extensions services across Greater London. Whether you're adding space with a side return, creating an open-plan kitchen-diner, or building a double-storey addition, we handle every detail from planning permission to final completion.

Double storey extensions are an efficient way to significantly increase the size of your home without moving. By building over two floors, you can combine a larger kitchen or living area downstairs with new bedrooms, en-suite bathrooms, or home offices upstairs. This approach spreads the cost of foundations and roofing across more space, often providing better value per square metre than building in two separate phases.

These projects generally require full planning permission due to their scale and impact on neighbouring properties. We prepare and submit all necessary drawings and documentation, considering sightlines, privacy, and roof design to maximise planning success. Our team manages substantial structural work, including new foundations, load-bearing walls, and steelwork, always prioritising safety and compliance. The end result is a substantial, permanent increase in space and flexibility, tailored precisely to your family’s needs.

Two-Level Expansion

Adds significant space on both ground and first floors in a single project.

Perfect for Growing Families

Ideal for households that need extra bedrooms, living areas, or play space.

Extra Upstairs Rooms

Can include en-suites, dressing rooms, or home offices on the upper level.

Better Value per m²

Often works out better value per square metre than doing separate single-storey and loft projects.

Designed to Suit Your Home

Tailored to complement the proportions, roofline, and style of your existing property.

Long-Term Flexibility

Provides long-term options for how you use and adapt your home over time.

Why Families Choose Us

20+ Years, Results
That Speak for
Themselves

Over 100 London families trusted us with their biggest investment. The kind of work that makes homeowners call us back for their next property.

You Decide Everything, We Handle Everything

Over 100 London families trusted us with their biggest investment. The kind of work that makes homeowners call us back for their next property.

Group 2661 Foundation and Finishing in Greater London

Work That Actually Gets Done On Time

Over 100 London families trusted us with their biggest investment. The kind of work that makes homeowners call us back for their next property.

Same Team From Quote to Completion

We work with the same qualified tradespeople on every job. Gas engineers, electricians, builders, finishers. They know our standards and they deliver. One point of contact for you, zero coordination headaches.

Honest Communication

We give you realistic timelines and pricing up front. If we discover something unexpected during the work, you know immediately. No hiding problems until it's too late.

Group 2661 Foundation and Finishing in Greater London

20+ Years, Results
That Speak for
Themselves

Over 100 London families trusted us with their biggest investment. The kind of work that makes homeowners call us back for their next property.

You Decide Everything, We Handle Everything

Over 100 London families trusted us with their biggest investment. The kind of work that makes homeowners call us back for their next property.

Same Team From Quote to Completion

We work with the same qualified tradespeople on every job. Gas engineers, electricians, builders, finishers. They know our standards and they deliver. One point of contact for you, zero coordination headaches.

Honest Communication

We give you realistic timelines and pricing up front. If we discover something unexpected during the work, you know immediately. No hiding problems until it's too late.

Work That Actually Gets Done On Time

Over 100 London families trusted us with their biggest investment. The kind of work that makes homeowners call us back for their next property.

icon Trusted Construction Services
icon Quality Craftsmanship & Reliability
icon Strong Foundations, Lasting Results
icon Professional & Committed Team
icon Trusted Construction Services
icon Quality Craftsmanship & Reliability
icon Strong Foundations, Lasting Results
icon Professional & Committed Team

Our Process

Simple. Straightforward. No Surprises.

Here’s exactly how we handle every project, from start to finish.

Get In Touch

Here's exactly how we handle every project, from start to finish.

We Listen & Advise

We measure everything, talk through your vision, and tell you what will actually work in your space.

Clear Quote

Fixed price. Fixed timeline. No surprises halfway through your project.

We Build It

Same team from day one to completion. Weekly progress photos. Direct line to Fares whenever you need answers.

Frequently Asked Questions

In almost all cases, yes. We handle the full planning process for you, including design justifications and any neighbour consultations.
Good design is key. We consider proportions, rooflines, and materials so the new structure feels in keeping with your existing house and street.
Yes, en-suites are a very common part of double storey extensions. We design plumbing, drainage, and ventilation to suit.
Timelines vary, but a typical project may take 14–18 weeks on site. We provide a clear programme and keep you updated throughout.
Many clients do, though there will be disruption. We discuss realistic expectations, safety measures, and phasing to make it manageable.

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