Water ingress in concrete: causes, damage and effective solutions

Water ingress is one of the main causes of deterioration in concrete structures. Foundations, retaining walls, underground car parks, tanks, tunnels and civil engineering works are constantly exposed to the effects of water, which can penetrate through porosity, micro-cracks, joints or points where services pass through.

If not addressed promptly, water ingress compromises not only the aesthetic appearance of the structure but also its durability. Moisture promotes corrosion of the reinforcement, spalling of the concrete cover, the formation of efflorescence and, in the most serious cases, a progressive decline in the structure’s performance.

For this reason, it is essential to understand the causes of water ingress and to implement appropriate prevention and repair measures right from the design and construction stages.

Although concrete is one of the strongest and most durable building materials, it is not completely waterproof. Its structure is characterised by a network of capillary pores which, under certain conditions, can allow water to pass through.

The risk increases when there are design or construction errors, or when the structure has deteriorated due to ageing. The main causes of water ingress are:

• high porosity of the concrete mix;
• sub-optimal water-to-cement ratio;
• insufficient compaction during casting;
• cracks caused by shrinkage or structural movements;
• incorrectly constructed construction joints;
• inadequately sealed pipe penetrations;
• hydrostatic pressure exerted by the ground;
• deterioration caused by freeze-thaw cycles.

Understanding the source of the water ingress is the first step towards identifying the most effective solution.

Water penetrating concrete can trigger a process of progressive deterioration which, if neglected, requires increasingly complex and costly repair work.

Among the most common consequences are:

• corrosion of the steel reinforcement;
• detachment of the concrete cover;
• accelerated carbonation;
• formation of salt efflorescence;
• persistent dampness in the premises;
• the appearance of mould;
• a reduction in the structure’s service life.

When water contains chlorides or other aggressive substances, the deterioration process can accelerate further.

Water ingress can affect any concrete structure, but some structures are particularly vulnerable. These include:

• foundations;
• retaining walls;
• underground car parks and garages;
• tanks and reservoirs;
• swimming pools;
• tunnels;
• plant rooms;
• manholes and drains;
• prefabricated elements.

In all these applications, it is essential to pay particular attention to joints, pour lines and service penetrations.

Prevention is always the most effective and cost-efficient solution.

Proper design of the concrete mix, good compaction during pouring and adequate curing can significantly reduce the permeability of the structure. At the same time, particular attention must be paid to construction details, which are often responsible for the majority of water ingress. Joints, pipe penetrations, precast elements and construction joints must be designed and sealed using specific systems.

A structure that is inspected regularly retains its performance for longer.

Visual inspections, checks on joints, checks for any cracks and prompt action help to limit deterioration and significantly reduce the costs of major maintenance. Taking action whilst leaks are still localised is generally much less costly than repairing a structure that has already deteriorated.

Concrete protection requires specific products and proven technical expertise.

For over forty years, Proind has been developing solutions for the construction sector, offering products designed to increase the durability of structures and resolve issues relating to water, joints and surface protection. The use of systems such as EXPANDER K1, HYDROSTOP and SIRIOSAN enables targeted intervention in the various situations that may lead to the occurrence of water ingress.

Water ingress into concrete is a problem that must not be underestimated. Identifying the causes quickly and implementing the correct preventive and remedial measures helps to preserve the safety, durability and value of structures.

Careful design, the correct execution of construction details and the use of specific products for sealing and protecting concrete are the key elements in creating reliable and long-lasting structures.