Basement Construction in London – Expert Builders for Reliable Foundation Work

Building a basement in London is one of the smartest ways to expand usable space without altering the footprint of your property. At KHB Piling Ltd, we specialise in complete basement construction and underpinning solutions for both residential and commercial clients across Greater London.

For more than a decade, our engineers and site teams have helped homeowners, architects and developers transform underused ground areas into functional living, storage or leisure spaces. From small basement extensions under terraced homes to complex multi-level basements in high-value areas like Kensington or Hampstead – we bring technical precision, clear communication and reliable project delivery.

Every basement requires a balance of engineering, safety and design. That’s why we combine deep knowledge of London’s soil conditions with advanced piling and underpinning techniques. The result: solid foundations and dry, usable basements built to last for generations.

Why Basement Construction in London Is a Smart Investment

London is famous for its limited space and high property values. Instead of moving, more property owners are choosing to build downwards. A well-designed basement can add between 20% and 30% to a property’s market value while creating flexible new space for modern living.

Our clients use their new basements for:

• Home offices and creative studios
• Fitness rooms, spas, and saunas
• Private cinemas or entertainment areas
• Wine cellars and secure storage
• Self-contained guest suites or rental spaces

Beyond lifestyle benefits, basement extensions improve structural integrity by reinforcing existing foundations and helping with better energy insulation.

Our Basement Construction Services in London

At KHB Piling Ltd, we handle every aspect of the basement construction process — from initial surveys to full project completion. Our services include:

• Feasibility Studies & Structural Design – Full site investigation, soil testing and load-bearing analysis to determine the best construction method.
• Underpinning & Piled Foundations – Traditional underpinning for smaller properties and mini-piled systems for deep or challenging sites.
• Excavation & Ground Retention – Careful excavation and retaining wall construction with minimal disruption to neighbours.
• Concrete & Waterproofing Systems – Structural slabs, tanking membranes and cavity drain systems to ensure watertight integrity.
• Drainage & Services Integration – Proper planning for water, power, and waste connections to keep your new basement functional.
• Finishing Works – Flooring, insulation, and surface preparation ready for your chosen interior design.

We tailor every project individually — no copy-paste solutions. Whether it’s a retrofit beneath a Victorian terrace or a new-build basement under a modern property, we plan every phase around your structural needs and local planning requirements.

The KHB Basement Construction Process

Building a basement in London is complex, but with the right process, it’s entirely manageable. Our approach ensures safety, transparency and efficiency at every stage:

1. Initial Consultation & Site Survey

We begin with a detailed conversation and on-site assessment. This helps us understand your goals and identify any planning or structural constraints early.

2. Structural & Engineering Design

Our qualified design engineers create structural drawings, load calculations and construction sequences — all approved in line with Building Control and BS standards.

3. Excavation & Temporary Support

Using modern excavation methods, we stabilise surrounding soil and structures with steel props or piles to prevent settlement or lateral movement.

4. Waterproofing & Retaining Walls

We use multi-layered waterproofing solutions including cavity drain membranes, waterproof concrete and internal tanking systems.

5. Structural Works & Concrete Slab

Our team pours reinforced slabs and retaining walls to form the core shell of your basement. Once cured, we install service conduits and drainage.

6. Finishing & Quality Assurance

Final inspections are conducted by our in-house engineer and third-party inspector where required. You receive full documentation for handover.

Why Choose KHB Piling Ltd?

There are many basement companies in London, but KHB Piling stands out for three reasons — expertise, reliability, and trust.

• Experienced Engineers: Decades of collective experience in basement design, piling, and underpinning.
• Local Knowledge: Deep understanding of London’s soil conditions and building regulations.
• Transparent Pricing: No hidden costs – every quotation is detailed and itemised.
• Health & Safety Focused: Strict site management, risk assessments, and compliance with CDM regulations.
• Fully Insured & Certified: £10M public liability cover and all operatives CSCS qualified.

Our philosophy is simple: build it once, build it right. We don’t take shortcuts, and we don’t outsource responsibility. Every site is managed directly by our own project supervisors.

Common Questions About Basement Construction in London

How long does it take to build a basement?

A standard single-level basement typically takes between 5 and 8 months to complete, depending on site conditions and permissions. Complex multi-level basements can extend to 12–15 months.

Do I need planning permission?

Many basements fall under permitted development, but properties in conservation areas or with structural complexities may require planning consent. We handle all applications and liaise with local authorities on your behalf.

Is it safe to build a basement under an existing house?

Yes — with proper underpinning and engineering control. Our team specialises in stabilising existing foundations safely, with minimal impact on neighbouring properties.

How much does basement construction cost?

Costs vary depending on depth, access and finish level. On average, expect £2,500–£3,500 per m² for complete structural works. Contact us for a tailored quotation.

Areas We Cover

We offer basement construction services across all London boroughs, including:
Chelsea, Kensington, Hampstead, Fulham, Richmond, Wimbledon, Camden, Islington, Clapham, and beyond.

We also undertake structural underpinning and piling projects in surrounding counties such as Surrey, Essex, Hertfordshire, and Kent.

Contact KHB Piling Ltd

If you’re planning a basement conversion, extension or new-build foundation in London, get in touch with KHB Piling Ltd today.

We offer free initial consultations and transparent, detailed quotations.
Our experienced project managers are ready to guide you through every stage — from feasibility study to final completion.

Call us today or fill out the online form to start planning your basement with confidence.