Foundations and Substructure

• Understand that the substructure of a building is the portion beneath the ground level, providing the base for the superstructure.
• Recognise the critical role the substructure plays in transferring the weight of the building to the ground and stabilising the structure.
• Know that there are two main types of foundation used in the substructure: shallow and deep foundations.
• Shallow foundations are typically used when the load-bearing surfaces are near to the surface, with types including strip, pad and raft foundations.
• Deep foundations, such as pile and pier foundations, are used when the load-bearing surface is deep below the ground level or the upper soil layers are not suitable for construction.
• Understand the factors affecting the choice of foundation including the nature and condition of the ground, the water table level, the type and weight of the building, and the load-bearing capacity of the soil.

Groundworks

• Appreciate that groundworks are the preliminary works that prepare the site for the substructure, involving soil testing, marking out, excavation, and concreting.
• Soil tests are crucial in ascertaining the load-bearing capacity of the soil, water table level, and the presence of contaminants.
• After marking out the building, excavation is carried out to create trenches for the foundations, with depths depending on the type of foundation and ground conditions.
• Concreting is the pouring of concrete into the trenches to create a solid base before the remedial brickwork begins.

Damp Proofing and Insulation

• Remember that damp proofing is essential in the substructure to prevent the penetration of moisture into the building.
• This can be achieved through the use of damp-proof membranes laid beneath the slab or by inserting a damp-proof course into the brickwork.
• Thermal insulation can also be installed to ensure the building maintains consistent temperatures and reduces energy consumption.
• Materials commonly used for insulation include polystyrene sheets, mineral wool, or multi-foil products.

Drainage and Services

• Understand the importance of suitable drainage systems in the substructure to prevent water build-up which may lead to dampness or damage to the foundations.
• Services such as gas, water, and electricity should also be considered at this stage, with routes for service pipes and ducts created before the superstructure is built.
• For example, sewage pipes are usually laid beneath the ground floor and connected to the public sewer system, while electricity and gas mains are commonly run through service ducts in the foundations.