Foundations in Greater London (181)

Foundations are a critical part of any construction project, providing the structural base to support your building over the long term.

People typically look for foundation builders when planning a new build, extension, or structural work that requires stable ground support.

A foundation builder will assess ground conditions, select the appropriate foundation type, and construct foundations that meet building regulations. For a commitment to quality and a job done right, search for foundations in London with Checkatrade.

What are building foundations?

Building foundations are the structural base of a property, designed to support its weight and transfer loads safely into the ground.

They prevent movement, reduce the risk of subsidence, and provide long-term stability for the structure above.

Signs you might need new foundations

• Planning a new build or extension
• Structural work that increases load
• Poor or variable ground conditions
• Building control requiring upgraded foundations
• Replacing or rebuilding an existing structure

Types of building foundations

The right foundation type depends on soil conditions, load requirements, and building design.

Shallow foundations

Used where ground conditions are stable and loads are relatively light.

• Strip foundations – Common for load-bearing walls and extensions
• Trench fill foundations – Trenches filled almost entirely with concrete to create a strong base, often used where soil conditions are less stable or trees are nearby
• Raft foundations – A single reinforced slab supporting the entire structure
• Pad foundations – Support localised loads, such as columns

Deep foundations

Used where surface soil cannot support the building load.

• Pile foundations – Steel or concrete piles driven deep into stable ground
• Caissons – Drilled shafts filled with reinforced concrete

How much do foundations cost?

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Foundation costs are influenced by:

• Foundation type – shallow vs deep foundations
• Ground conditions – soil stability and excavation needs
• Size and depth – larger structures require more materials
• Reinforcement requirements – steel and concrete specifications
• Site access – restricted access can increase labour time

New foundations vs foundation repairs

New foundations

• Installed for new builds or extensions
• Designed to meet current regulations
• Planned as part of construction

Foundation repairs

• Address existing structural movement
• Often more complex and disruptive
• May require specialist assessment

Choosing the correct option depends on whether the structure already exists.

How long does it take to construct foundations?

Foundation construction usually takes 1–3 weeks, depending on depth, ground conditions, and weather.

This includes excavation, reinforcement, pouring, and curing time.

How long do foundations last?

Well-constructed foundations are designed to last the lifetime of the building, provided ground conditions remain stable and drainage is maintained.

Maintenance considerations for foundations

• Ensure surface water drains away from the building
• Avoid planting trees close to foundations
• Monitor for cracks or movement
• Address drainage issues promptly
• Follow building control guidance for ongoing works

What should be included in your quote for foundations?

When comparing quotes for foundations in London, ensure you receive:

• Foundation type and depth specification
• Excavation and ground preparation details
• Concrete and reinforcement specifications
• Waste removal and soil disposal
• Building control or inspection stages
• Timescales for completion

Common mistakes to avoid with building foundations

• Choosing foundation types without soil assessment
• Underestimating excavation depth
• Ignoring drainage requirements
• Proceeding without building control approval
• Comparing quotes without matching specifications

Tips for hiring a foundation builder in your area

Before hiring a foundation builder near you:

• Read reviews on Checkatrade
• Check which foundation types they construct
• Compare several quotes
• Confirm experience with similar projects
• Ask how inspections and approvals are handled

For tradespeople committed to quality and a job done right, search for foundations in London with Checkatrade.