By Gert Schmidt
By deploying state-of-the-art techniques, reputable waterproofing contractors significantly prolong structural asset lifecycles.
Although concrete is water-resistant, variations in ingredients of concrete mixes, influence its porosity. A vast network of pores and capillaries exist in concrete that allow the ingress of water containing potentially harmful substances. Exposed concrete structures, such as public and industrial infrastructure, are especially at risk. Contaminants, such as chloride-ions, reach the passive oxide layer on reinforcing steel and damage it. This initiates active corrosion which compromises the durability of the structure.
Chloride diffusion can take many years to reach reinforcing steel. Obviously, prolonging this period will raise the lifecycle of concrete structures. Waterproofing contractors refer to this as “time-to-corrosion initiation”. Engineers can model the time it takes for chlorides to travel through the concrete and initiate reinforcing steel corrosion. This is done mathematically with software that incorporates Fick’s laws of diffusion [https://www.sciencedirect.com/topics/engineering/ficks-law]. Chloride diffusion is a function of many factors. They include the thickness of the concrete cover over the reinforcement; quality of the concrete; and the environment. An example of software used by engineers to calculate chloride diffusion rates is https://www.life-365.org/download/Life-365_v2.2.3_Users_Manual.pdf.
Meanwhile, the time period from corrosion initiation to first signs of damage is referred to as “active corrosion time”. This timeframe can also be modelled with equations that calculate the time until concrete cracks. However, the priority is to prolong the time that chloride-ions take to reach the reinforcement.
Other moisture-related problems include cracking and efflorescence, which is the formation of white, powdery deposits on concrete surfaces.
Waterproofing contractors ensure successful waterproofing
Waterproofing contractors apply best practices to ensure successful concrete waterproofing.
Proper installation and application of waterproofing materials are important. This entails training in the correct use of waterproofing materials deployed. Hindle Mason Projects is an approved applicator of quality concrete repair and waterproofing materials. This agreement entails also undergoing regular training in the correct application of these products by the manufacturers. Furthermore, we receive valuable technical support from these companies in our supply chain. Therefore, our workmanship can be guaranteed to the maximum available term.
An important consideration is to ensure that the substrate is adequately prepared, and cracks repaired before applying the waterproofing system. This will create a reliable and watertight barrier.
The correct application of the waterproofing system is a critical phase. It entails the even and uniform application of the selected waterproofing system on the prepared surface. Techniques deployed include brushing, spraying, rolling or trowelling, depending on the choice of waterproofing material. It is vital to ensure complete coverage and thickness of the waterproofing layer. In this way, a seamless and watertight barrier is created that effectively prevents moisture infiltration.
After application, the system needs to set and adhere correctly to the concrete substrate. The curing period may vary depending on the type of waterproofing material and environmental conditions. During this timeframe, the waterproofing material undergoes chemical reactions and bonds with the concrete. This ensures a durable and long-lasting seal. Throughout the curing period, regular inspections are undertaken to verify that the waterproofing material is achieving these parameters. Any defects are promptly addressed to maintain the integrity of the waterproofing system.
These steps will help to achieve a long-lasting, effective and watertight solution.
Waterproofing contractors bring skills and experience
Waterproofing contractors bring specialist skills and experience to your projects, including a sound understanding of conditions and constraints. For example, temperature, humidity and weather conditions can influence application and curing of waterproofing materials. Therefore, careful planning and scheduling are necessary to ensure that waterproofing is undertaken during favourable environmental conditions.
Waterproofing contractors also know which system is suitable for specific applications. For example, traditional bituminous sheet membranes may not be well-suited for structures with complex geometries or irregular surfaces. This is considering the complexity involved in their installation in these instances. Similarly, crystalline waterproofing systems may not be the ideal choice for concrete structures exposed to aggressive chemical environments. This is considering that they do not provide sufficient resistance against chemical infiltration.
The selection of the most suitable waterproofing system is based on many factors. These include the type of concrete; location of the structure; or intended use.
Techniques deployed by waterproofing contractors
Therefore, the techniques and materials deployed by waterproofing contractors vary. No two projects are ever alike. In most instances, waterproofing contractors will have to tailor a waterproofing solution for their clients. This while working closely with engineering teams who undertake structural inspections and the repair designs.
Interventions may include the application of specialised liquid or semi-liquid materials directly onto concrete surfaces. They form a seamless, waterproof membrane that prevents water penetration. These coatings are available in various formulations, including acrylic, epoxy and polyurethane. Each offer unique advantages, such as chemical resistance, flexibility and durability.
Crystalline waterproofing is another unique technique deployed by Hindle Mason Projects. Chemicals or compounds that crystalise when in contact with water penetrate the concrete matrix. They then fill micro-cracks and capillaries that block water pathways. Over time, these crystals continue to grow and self-seal any potential water-entry points. This technique is particularly effective for addressing minor cracks and can provide long-term protection.
We are also at the cutting-edge of post-initial set applied colloidal silica technology. These nano particles penetrate concrete deeply to fill capillary and pore space with more concrete after a single spray-applied application. Refer to https://www.spraylockafrica.co.za/colloidal-silica-raises-concrete-durability/.
Then there are concrete sealers that create a protective barrier on the exterior of concrete structures. These form a thin film or penetrate the concrete surface to reduce water absorption and prevent moisture infiltration. There are various types, namely acrylic, silane, siloxane and epoxy based. Each offer specific benefits such as UV resistance and breathability.
Cementitious waterproofing systems involve the use of cement-based materials to shield concrete. They are mixed with polymers or additives to create an impermeable waterproof barrier. These materials are applied as a slurry or mortar directly to the concrete surface. Cementitious waterproofing is often used for below-grade applications, such as basements and foundations.
Waterproofing contractors are concrete specialists
Waterproofing contractors are also concrete repair specialists. Therefore, they are also tasked with rebuilding compromised sections of structures. In these instances, Hindle Mason Projects uses waterproofing admixtures to alter concrete properties. This makes it inherently resistant to water penetration. Reducing the capillary pore size to improve its impermeability, these are a proactive and longer-lasting approach to waterproofing.
Hindle Mason Projects’ robust supply chain consists of the following manufacturers of high-quality waterproofing solutions:
- Waterproofing Products & Systems (sika.com)
- All Waterproofing Products | a.b.e.® Saint-Gobain (abe.co.za)
- Waterproofing Products | Mapei
- WATERPROOFING – Cementitious waterproofing, protection & repair products. (euclidchemical.co.za)
- PENETRON | Crystalline Waterproofing | PENETRON Total Concrete Protection
- Products – Spraylock Africa
Learn more about Hindle Mason Projects. www.hindlemason.co.za
Schmidt is a Director of Hindle Mason Projects