Foundation design in Swansea demands a thorough understanding of the region's complex geology, which ranges from glacial till and alluvial deposits in the coastal plains to the Coal Measures sandstone, mudstone, and shale that dominate the hinterland. A successful project, whether a residential extension or a major commercial development, begins with a robust ground investigation to characterise these variable ground conditions. This critical phase must also address localised risks such as shallow mine workings, a legacy of Swansea's industrial past, and the potential for sulphate attack on buried concrete from certain Mercia Mudstone Group strata, all in strict accordance with the recommendations of BRE Special Digest 1.
Our methodology is deeply rooted in the Eurocode 7 framework, specifically BS EN 1997-2, which we use to derive characteristic ground properties for both ultimate limit state (ULS) and serviceability limit state (SLS) designs. We move beyond basic borehole logging by employing advanced in-situ techniques like the Cone Penetration Test (CPT) to provide a continuous profile of soil behaviour, which is exceptionally effective for profiling the soft estuarine clays found along the Tawe corridor. For granular fill and sand layers, precise field density testing using the sand cone method is essential for validating compaction to the standards required by the Specification for Highway Works, ensuring any engineered fill platform can safely support the intended foundation loads.
Typical projects in Swansea reflect its varied landscape, from lightweight residential schemes on improved ground to heavy industrial structures. In the coastal SA1 development area, we frequently design piled foundations to transfer loads through compressible alluvium and underlying dense glacial deposits, a solution we validate with comprehensive in-situ and laboratory testing. For domestic projects on the swelling clays found to the north of the city, our designs often specify trench-fill foundations at a depth that mitigates the effects of seasonal moisture variation, with the specific depth informed by our precise Atterberg limits testing to determine the soil's plasticity index.
Our process delivers a fully integrated design package, from the initial desk study and interpretive report to detailed foundation drawings and construction specifications. We provide clear, actionable recommendations for shallow pad and strip footings, trench-fill, or deep piled solutions, with all calculations and deliverables fully compliant with the NHBC Standards and local building control requirements. By combining a forensic understanding of Swansea's geology with pragmatic, code-compliant engineering, we de-risk the most critical phase of your project, ensuring your foundation system is safe, optimised, and durable for its intended design life.