4 + 1 cases where concrete structures need MasterSeal waterproofing solutions

Posted by Albert Berenguel , Vanja Landeck - 28 January, 2021

"Keeping concrete dry minimizes freezing-and-thawing damage, alkali-aggregate reaction, most types of sulphate attack, de-icer salt scaling, and carbonation.

For new concrete construction of good quality, addressing cracks; providing treatment with penetrating sealers, coatings, or membranes; and other proactive maintenance over the life of a structure can postpone repair needs almost indefinitely.”


International Concrete Repair Institute ("ICRI") Committee 160: “Sustainability for repairing and maintaining concrete and masonry buildings”


Knowing that one of the factors that significantly influences the durability of concrete is keeping water out of the structure, the question we must ask is: Can concrete be watertight?

The watertightness of concrete is largely dependent on the water/cement ratio and the degree of compaction. The use of superplasticizing admixtures and supplementary mineral materials combined with specific waterproofing admixtures enable concrete mix designs with adequate mechanical strength and structural density, whilst maintaining workability and excellent compaction.

Further information about how you to manufacture watertight concrete and keep structures dry and safe using Master Builders Solutions can be found here: https://blog.master-builders-solutions.com/en/looking-for-dry-and-safe-structures-waterproof-your-concrete

Nevertheless, there are at least, 5 cases where concrete structures still require surface membranes or other waterproofing systems.

Let us review them:

1. When concrete is not properly installed:

In practice the instalment of concrete is not always as easy and straightforward as it seems. Even with the best concrete mix, mistakes during the preparation, placement and curing processes can lead to some undesired results: cold joints between concrete batches, lack of sufficient compaction, premature removal of formwork, extreme weather or worse.

Cracks, honeycombs or other surface defects will affect the ability of the concrete to repel water and will eventually require the use of MasterEmaco repair mortars and the application of MasterSeal waterproofing membranes such as MasterSeal 6100 FX to restore the uniformity and continuity of the surface to repel water and prevent damage from carbonation.

2. In chemically aggressive environments:

Concrete and cement-based mortars have limited chemical resistance. Regardless of the composition or the admixtures used, the cement and calcareous aggregate in hydraulic cement concrete cannot withstand the dissolving effects of acidic substances with a pH of 3 or lower.

In such extreme environments in industrial or waste water treatment plants, the use of waterproofing membranes with high chemical resistance properties such as MasterSeal 7000 CR will isolate and protect the concrete surface from these aggressive substances. 



3. On concrete roof slabs:

Concrete roof slabs are used in structures designed to have special use of the roof such as car park decks. The roof protects not only the structure itself but also the goods and equipment installed below.

Therefore, a good waterproofing system will improve the durability and service life of the building and whilst protecting the investment and assets below.

MasterSeal Roof systems provide secure waterproofing for all types of roof and MasterSeal Traffic systems offer additional mechanical wear and abrasion resistance against traffic in car parks.

4. For cracks in structures with movement:

Opposite to the reinforcing steel, concrete has quite a limited deformation capacity. Meaning that every potential movement or force applied to the structure must be carefully analysed and predicted because when deformations exceed the elastic capacity of the concrete, cracks will appear. Gain a deeper insight into this phenomenon from our post “Why does concrete crack? Part 1 – The main reasons”


In these cases, the application of highly elastic waterproofing membranes such as MasterSeal M 689 will form a dynamic crack-bridging membrane that will also permanently prevent water ingress into the concrete structure.


But even in the best-case scenario, when everything runs according to plan and there are no cracks, no surface damage and the concrete is not exposed to aggressive substances, concrete structures need expansion joints at regular intervals between concrete elements.

+1 Concrete elements are finite:

The size of concrete elements is limited, either by production restrictions (eg. precast elemnts) or to compensate for the coefficient of thermal expansion caused by temperature changes.

Concrete expansion joints are thin gaps between two elements which accommodate the naturally occurring expansion and contraction movement of concrete from temperature changes, the curing process or foundation settlement.

These joints, interrupting the continuity of the protective surface are also penetration “highways” for water and need to be treated using elastic joint sealants such as MasterSeal NP 474 or MasterSeal 930 elastic tapes.

To summarize…

Water is one of the most aggressive agents and is the most common cause of damage to concrete structures. We have included a summary of cases where the application of MasterSeal waterproofing membranes and sealants extends the service life of the concrete structures even when the concrete mix has been carefully designed:


Watertightness risks


For more information

Concrete not properly compacted

Cold joints, cracks, honeycombs…

All kind of exposed concrete elements

MasterSeal 6100 FX

Chemically aggressive environments

Degradation of concrete

Waste water treatment plants; Industrial plants

MasterSeal 7000 CR

Concrete roof slabs

Penetration and asset damages


Parking decks

MasterSeal Roof systems

MasterSeal Traffic systems

Structures with movements

Limited tensile strength of concrete

Water reservoirs;

MasterSeal M 689

Concrete elements are finite

Expansion joints


channels, dams, tanks …

MasterSeal NP 474

MasterSeal 930


Want to know more about waterproofing? Here are some recommended readings:

Waterproofing concrete - the simple way to reduce the environmental impact of concrete structures

Sustainable benefits with MasterSeal 6100 FX cementitious waterproofing membrane


Topics: Concrete structures, Waterproofing, MasterSeal 7000 CR

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