Piled Raft Foundation Contractors
The best solution for unstable soil. We design and build piled raft foundations in Essex, Cambridge and London
- 20 Years Experience
- Family Run Business
- Specialists in Piling
- Complete Client Satisfaction
Prime Piling is a specialist piled raft foundation contractor serving Essex, London, Hertfordshire and Cambridgeshire. With over 20 years of experience installing piled raft foundations, we design and install complete foundation solutions for projects where ground conditions require the combined strength of deep piling and a raft foundation slab.
As experienced raft foundation contractors, we provide complete design, installation and Building Regulations approval support for domestic and commercial projects. Our piled raft foundation services include site investigation, structural engineer design, pile installation, raft construction, and Building Control liaison throughout Essex, London, Cambridge and surrounding areas.
Mini Piled Underpinning
What is it piled raft foundation?
A piled raft foundation is a clever combination of both pile foundation and raft foundation. Let’s break it down:
Piles: These are vertical structural elements driven into the ground. They can transfer loads from the superstructure to deeper, more stable soil or rock layers. Piles are often used when the upper layers of soil are weak or compressible.
Raft: A raft foundation (also known as a mat foundation) is a large, flat slab that spreads the load from the building over a wider area. It rests directly on the soil or rock beneath it.
Piled Raft: Now, imagine constructing piles first. These piles penetrate the ground, providing additional support. Next, a raft (the flat foundation slab) is placed, incorporating all the piles. The key factor in designing a piled raft foundation is the interaction between the piles, soil, and raft.
- Pile-Soil Interaction: How the piles interact with the surrounding soil.
- Pile-Pile Interaction: Consideration of the interaction between adjacent piles.
- Raft-Soil Interaction: Understanding how the raft interacts with the soil.
- Pile-Raft Interaction: Ensuring effective load transfer between the piles and the raft.
Advantages of Piled Raft Foundations
- Reduced Settlement: The addition of piles minimizes overall settlement and differential settlement.
- Improved Lateral Load Resistance: Piled rafts enhance the structure’s ability to resist horizontal forces.
- High Axial Load Applications: They’re commonly used in high-rise buildings with substantial axial loads.
- When Rock Socketing Isn’t Feasible: In cases where piles can’t be socketed into rock due to its absence, piled rafts provide an alternative solution.
Piled Raft Foundation Design Considerations
Designing a piled raft foundation requires careful analysis to ensure optimal performance. Our structural engineers assess:
Ultimate Load Capacity
Piled raft foundations must support vertical loads, lateral forces, and moment loading. We calculate the optimal number and depth of piles to achieve required load capacity.
Settlement Control
A key advantage of piled raft foundations is settlement control. We design pile spacing and raft reinforcement to limit both total and differential settlement.
Raft Moment and Shears
Ensuring structural integrity through proper reinforcement design and load distribution analysis.
Pile Loads and Moments
Designing piles effectively to transfer building loads to stable ground while optimizing foundation costs.
Our Services
Mini Piling
Prime Piling has built up to become one of the best Mini Piled Underpinning service providers.
SCD Piling
SCD (Steel Cased Driven) Piling is a bottom-driven piling using a vibrating mole or a drop hammer piling rig
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Our Recent Piled Raft Foundation Work
Our Piled Raft Foundation Services in Essex, London & Hertfordshire
Prime Piling has successfully installed piled raft foundations across Essex, London, Hertfordshire and Cambridge for over 20 years. Our experience covers domestic extensions, new builds, and commercial developments on challenging ground conditions.
Complete Piled Raft Foundation Package
We provide everything you need for your piled raft foundation project:
- Site Investigation: Ground assessment, soil testing, and bearing capacity analysis to determine foundation requirements
- Structural Engineer Design: Professional design and calculations for Building Regulations approval
- Pile Installation: Mini piling, SCD piling, or SFA piling depending on site conditions and access
- Raft Construction: Reinforced concrete raft slab incorporating all pile heads
- Building Control Liaison: Complete coordination and inspection support
Areas We Serve for Piled Raft Foundation Installation
Essex: Chelmsford, Colchester, Brentwood, Basildon, Bishops Stortford, and surrounding areas
London: All London boroughs from our Enfield office, with expertise in restricted access sites
Hertfordshire: St Albans, Hatfield, Welwyn Garden City, Hemel Hempstead, Stevenage, and surrounding towns
Cambridge & Cambridgeshire: Cambridge city, Ely, Huntingdon, and surrounding villages from our Cambridge office
As professional raft foundation contractors, we understand local ground conditions including Essex London Clay, Cambridge high water tables, and London restricted access challenges. Contact us for expert piled raft foundation advice for your project.
Piled Raft Foundation vs. Regular Raft Foundation
A regular raft foundation is a reinforced concrete slab resting directly on the ground, suitable when soil bearing capacity is adequate and loads are moderate.
A piled raft foundation adds deep piles penetrating through weak upper soil to stable ground at depth. The raft incorporates pile heads, creating a combined system that provides:
- Greater load capacity than raft alone
- Reduced settlement and differential movement
- Ability to work on poor ground conditions (soft clay, made ground, high water table)
- Better performance when soil varies across the site
Choose a piled raft foundation when your ground investigation reveals inadequate bearing capacity for a raft-only foundation, or when settlement control is critical for extensions to existing buildings.
Prime Piling provides expert assessment to determine whether a piled raft foundation is the right solution for your Essex, London, or Cambridge project.
Frequently Asked Questions
Piling is the process of inserting structural piles into the ground that will become the base of the building. Piles are required where soil and earth are performing poorly and are used to spread the load of a building and firm the ground. They are a cost-effective approach to combating corrosion and are proven to significantly improve the life expectancy of a structure
For piled raft foundations, excavation depth is typically 600-900mm for the raft slab, significantly less than traditional deep strip foundations. The piles penetrate deeper (typically 4-12 metres) but require minimal surface excavation. This makes piled raft foundations ideal for sites with high water tables or restricted access where deep excavation would be difficult.
Piling is used when ground conditions are poor, such as soft clay, made ground, or high water table. Piled raft foundations are particularly effective when upper soil layers are weak but full piling would be uneconomical. Common applications include house extensions in Essex on London Clay, new builds in Cambridge with high water tables, and London properties with restricted access requiring mini piling solutions.
Piled raft foundation costs for domestic projects typically range from £8,000 to £15,000 depending on pile number, depth, ground conditions, and raft size. A standard single-storey extension with 8-10 piles at 5-7 metres depth costs approximately £10,000-£12,000 including design, installation, and Building Control support. Contact Prime Piling for a detailed quotation based on your specific site conditions.
Piled raft foundations provide superior load capacity, reduced settlement control, and cost-effectiveness compared to full piling. A piled raft foundation is ideal when ground conditions require deep support but full piling would be uneconomical. They offer flexibility for difficult ground conditions including soft clay, made ground, and high water tables common in Essex, London, and Cambridge.
The job of the pile is to distribute the weight of the structure evenly. They are placed into the ground using a pile driver. Holding the piles perfectly vertical, this machine hammers each structure into the ground and also acts as a crane.
A typical domestic piled raft foundation project takes 1-2 weeks from pile installation to completed raft. Timeline includes: pile installation 1-3 days, raft excavation and preparation 1-2 days, raft construction 2-3 days, concrete curing 5-7 days. Total project time from site investigation to Building Control approval is typically 3-4 weeks.
Mini piling uses compact equipment to install piles in restricted access locations. Our mini piling rigs can work in spaces as narrow as 700mm with low headroom (1.85m clearance), making them ideal for piled raft foundations at London terraced houses, Essex properties with narrow side access, or Cambridge city centre sites where standard piling equipment cannot operate.
Yes, all piled raft foundations require Building Regulations Part A approval. Your foundation must be designed by a qualified structural engineer, and Building Control will inspect at key stages: after pile installation, during raft reinforcement, and before concrete pour. Prime Piling coordinates all Building Control liaison as part of our service, ensuring your piled raft foundation achieves full compliance and approval.
We install piled raft foundations throughout Essex, London, Hertfordshire and Cambridge. Our piled raft foundation projects include domestic extensions, new builds, and commercial developments across all areas. With offices in Enfield (London), Bishops Stortford (Essex), and Cambridge, we provide rapid response and local expertise for your piled raft foundation requirements.
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