Casting Over-Site or German Floor Concrete

Over site concrete or German floor as is often referred to by the laymen is the mass concrete that is

poured to cover the entire length and breadth of a building on the ground floor. It serves as a source of additional support to the structural stability of building especially storied buildings. It is the mass concrete which is cast after the damp proof course (DPC) level has been established.

When casting an over-site or German concrete the following steps must strictly observed for a sound and good over-site concrete to be achieved:

• The soil underneath should be laterite and not any other kinds of soil especially loose and peat soil. The filling requires sand that can be compacted to have a good sustainability and the ability to carry the compressive load of concrete coming on top of it. A loose soil in this case will not allow the soil to be easily rammed to compaction hence won’t be good for the task.

• Apply wire mesh or BRC. The wire mesh forms a ring that helps the concrete to be able to carry its weight. Due to the tensile strength of this wire mesh the concrete is most unlikely to cave in when the soil underneath it is getting more compacted from the weight of the concrete as you pour it. So make sure you spread it round the building as specified.

• Use a membrane or polythene-like material that can be able to block water from rising from the soil to the ground floor or slab. This is especially where the ground is waterlogged.

• Follow the recommended mixture ratio of the concrete for you to have strong concrete cast.

• Prior to casting make sure all the materials, equipment and the needed personnel are in place and adequate otherwise some part of the cast might not be completed and this will definitely cause lack of a cohesive single bonded foundation.

• Ensure that proper level all-round the building is established by use of plumb, spirit level and trace ropes.  This will ensure that you avoid the likelihood of having a poorly skewed house. Foundation is the root of the beauty of any house just as it applies to every facet of life.

• After done with casting, take at least two or so days before removing the sides that were used to prevent the concrete from running off the edge. This will help to avoid cracks around the edges when the sides are removed especially when the concrete mixture ratio is weak.

NOTE

The columns/pillars coming from the base of the foundation should be properly aligned and protrude out of the cast concrete slab by at least 450mm.