Underpinning in London – Secure, Correct and Engineer-Led

At KHB Piling LTD we help property owners, contractors and developers deal with one of the most serious issues in construction – loss of foundation stability. Our underpinning service is designed for London conditions: older housing stock, mixed ground, extensions added over time, nearby excavations and subsidence caused by clay movement.

We deliver underpinning, local excavation, basement preparation and associated foundation works for both residential and commercial buildings. Every project is assessed by our technical team first, so the method we propose is the one that actually solves the problem – not just hides the symptoms.

If you have cracking walls, dropping floors, doors that no longer close, or you are planning to load the existing structure with a new storey or basement – underpinning is the correct first step.

What Is Underpinning and When Do You Need It?

Underpinning is the controlled process of strengthening an existing foundation so it can safely carry more load or recover from movement. In London it is most often needed when:

• the original foundation was too shallow for current use,
• ground conditions have changed (tree roots, drying clay, leaking drains),
• neighbouring works or basement digging have affected your structure,
• you want to add a rear/side extension or a basement under an existing house,
• you can see progressive cracking in walls or at window/door heads.

Without corrective underpinning, settlement usually continues and repairs become more expensive over time. Our approach is always: diagnose → stop movement → strengthen → record.

Underpinning Methods We Use

Different buildings and different soils need different solutions. That’s why we don’t offer one single method – we match the technique to the building.

• Mass Concrete Underpinning – the traditional, proven way. We excavate short controlled bays under the existing footing and fill them with reinforced concrete, one by one. Good for low to medium depth foundations and period houses.
• Beam-and-Base Underpinning – we form concrete bases under the wall and link them with a reinforced beam that picks up and redistributes the load. Ideal when the existing foundation is uneven or we need to span services.
• Mini-Piled Underpinning – used where the good bearing strata is deeper or access is restricted. Small diameter piles transfer the load down to competent ground. Very useful in London basements and tight sites.
• Raft / Slab Solutions – for buildings on very poor or variable soils we can form a new reinforced concrete raft that spreads the load over a wider area, reducing differential settlement.

Before we choose a method we review drawings, the condition of the existing footings, nearby structures and any available site investigation.

Why KHB Piling LTD?

• Engineer-led service: we don’t guess underpinning depth – we calculate it.
• London experience: we work every week on Victorian/Edwardian houses, party-wall conditions and sites with limited access.
• Measured, safe excavation: we only open as much of the foundation as can be supported that day.
• Documentation for Building Control: we issue records, concrete tickets and method statements.
• Co-operation with your architect/SE: we can work to your designer’s details or provide our own.

Typical Problems Underpinning Solves

Underpinning is not just for “old” buildings – it’s for buildings that are being asked to do more than they were designed for. Common triggers:

• cracks wider than 3 mm appearing or reopening,
• sloping or bouncing floors,
• visible movement at bay windows or rear extensions,
• manhole / drain failures causing local washout,
• planned basement excavation next to or under the house.

In each of these cases, stabilising the foundation first protects the rest of the structure and avoids repeat repairs.

Additional Foundation Services

Because we are a piling and groundworks company, we can deliver the whole package – not just the underpinning itself:

• site and ground investigation (to understand the cause of movement),
• mini piling and micro piling where deeper support is needed,
• basement excavation and forming retaining walls,
• load testing and as-built reporting,
• drain and service protection during works.

This means you deal with one contractor instead of coordinating several trades in a confined area.

How to Start

If you suspect foundation movement or you are planning an extension on an older property, speak to us first. We can attend site, review the structure and advise on the most cost-effective underpinning method.

Contact KHB Piling LTD to arrange a visit or send us your drawings.
Tel: +44 7821 836407 · Email: info@khb-piling.co.uk