Concrete slab deterioration, in the Springfield Lakes area, a Southern suburb of Brisbane,

Deterioration to a concrete slab. Identified by Peter Weddell, owner/operator of  Qld Home Buyers Inspection Service.

Rising damp to concrete slab edge of a new house causing deterioration.

Concrete slab with deterioration

With closer observation you will see pitting of the concrete edge.

Problems with rising damp and deterioration:

If rising damp occurs to other slab edges where they are supporting timber walls. This can cause rot to the lower timber wall framing (or rust to steel framing) if water impervious barriers have not been fitted between the slab and framing. Rot may also occur to skirting boards and plaster.

Cause of defect:

This can occur from salts in the soil, rising damp also the plastic membrane not being wrapped around edge of the slab far enough. This is a very common occurrence and unfortunately further deterioration is most likely. The degree of further damage in the future is not possible to determine, only time will tell.

Degree of concern:

Whether it is a major concern or not would be dependent on the degree of deterioration also over what time frame it has occurred.

Rectification:

Drilling into the concrete edge and injecting a chemical barrier may help reduce further deterioration. An expert in rising damp would have to be consulted for advice on rectification and if their method can be guaranteed, also over what time frame.

Important note:

If this problem has occurred to concrete slab edges, it may also occur to mortar and bricks of the house lower external walls. The external walls must be closely monitored periodically. Consult an expert if deterioration occurs, so they can assess the situation and advise if rectification is required.

Some related information that may be of use:

Wikipedia regarding Concrete degradation

For independent Building Inspections Brisbane in all suburbs, Qld Home Buyers Inspection Service. qbis.com.au