Building Methods & Construction Technology

Solid Ground Floors

Ground FloorsThere are two main types of ground floors:

• Solid floors. • Hollow floors.

Concrete ground floors consist of the following components, in order:

• Hardcore • Blinding• DP membrane • Site concrete• Insulation • A floor finish

Section Through a Solid Ground Floor.

Ground levelFloor finish Insulation

Site concrete

Blinding

DP membraneHardcore

Components and Sequence of Building a Solid Ground Floor

Hardcore and blindingHardcore is used to provide a firm and

solid base on which to place the concrete slab.

Blinding is usually building sand spread on top of the hardcore to provide an even bed and to prevent any puncturing of the DPC membrane by sharp pieces of hardcore.

The damp-proof membrane sheeting should be laid on top of the blinding and should lapped onto the horizontal DPC of the brickwork to form a continuous membrane.

Ground level DP Membrane laid onto blinding and lapped into the internal brickwork

Blinding sand

Hardcore

Compaction of hardcoreHardcore should be laid in 100mm layers maximum, and each layer should be well compacted and consolidated. This should prevent any unacceptable settlement beneath the finished solid floor. The main item of small plant which is used to compact hardcore is a Plate Compactor.

Insulation

Insulation should always be laid above the DPM membrane preferably under the floor slab, or alternatively under the floor finish. If it is not it could cause the insulation to become damp which will impair its performance.

The Building Regulations require ground floors to be insulated to prevent heat loss. There are several types of insulation available such as expanded polystyrene and rigid foam insulation.

Insulation positioned below

the floor finish

Insulation positioned below

the floor slab

Ground level

Ground level

Floor finish

Floor finish Insulation

Insulation

Site concrete

Site concrete

DPM

DPM

Blinding

BlindingHardcore

Hardcore

Oversite concreteThe concrete placed in between the ground floor walls is known as ‘oversite concrete’. The brickwork or blockwork on the internal walls acts as shuttering for the concrete. Oversite concrete should be at least 100mm thick.