Detailed Classification of Waterproofing Engineering! Understand at a Glance!

Publish Date: 2024-03-25 2Views

Detailed classification of waterproofing engineering

Classification of Waterproofing Engineering

Categorized by Material Form

1.Rigid Waterproof MaterialsWorkmanship

The workmanship of rigid waterproof materials mainly refers to the construction of waterproof mortar or waterproof concrete.

Rigid waterproof materials refer to materials made from cement, sand, and gravel as raw materials, or with added small amounts of additives, high-molecular polymers, etc. By reasonably adjusting the mix ratio of cement mortar or concrete, they reduce or suppress porosity, improve pore structure characteristics, enhance the tightness between material interfaces, and are formulated into waterproof materials such as cement mortar and concrete with certain anti-permeability performance.

2. Flexible Waterproof Materials Workmanship

Waterproof coatings (also known as flexible waterproof materials) are a type of fluid or semi-fluid substance. Applied to the base surface, they cure through solvent evaporation, water dispersion, or chemical reactions between components, forming an elastic film that isolates the surface from water, serving waterproofing and anti-corrosion functions.

China's research and application of waterproof coatings began in the 1960s, initially mainly based on asphalt-based waterproof coatings. In recent decades, it has evolved from traditional asphalt-based coatings to high-polymer modified asphalt coatings and polymer-based waterproof coatings.High-polymer Modified Asphalt Coatingsand polymer-based waterproof coatings, producing low-, medium-, and high-grade product series. With abundant production volume and variety, these advancements have significantly promoted the development of building waterproofing projects.

Flexible waterproof coating construction is divided into two types based on coating thickness: thin-coating and thick-coating methods. Thin coatings typically use spraying or brushing techniques, while thick coatings commonly use troweling or rolling methods. Due to differences in coating properties, the tools and techniques used vary accordingly. Depending on project needs, waterproof coatings can be applied as pure films or combined with reinforcing materials.Reinforcement MaterialsCoatings (with glass fiber mesh or fiber, polyamide fiber felt) are used to create single-layer, double-layer, triple-layer, or multi-layer coatings.

3. Waterproof Membrane Workmanship

Waterproof membranes are a major category of building waterproofing materials. They are generally classified into three types: asphalt-based waterproof membranes using asphalt as the main raw material, high-polymer modified asphalt waterproof membranes using modified asphalt as the main raw material, and polymer-based waterproof membranes using polymer materials as the main raw material.Polymer-Based MaterialsThe first type is traditional waterproof membranes, but their substrate materials have seen new developments and applications. They are still widely used in China’s waterproofing projects. The latter two types represent the future direction of membrane development due to their superior performance and are currently being actively developed and applied in China.

Common construction methods for membrane waterproofing include hot-melt method, cold-adhesive method, hot-air welding, self-adhesive method, mechanical fastening, and other installation techniques.

4. Metal Sheet (Plate) Waterproofing Workmanship

Metal sheet (plate) waterproofing is primarily used to construct roofing systems by combining structural layers and waterproof layers into one unit using metal sheets as the primary material. Metal sheets come in various types, including copper sheets, brass-copper sheets, aluminum alloy sheets, bronze-aluminum alloy sheets, nickel-aluminum alloy sheets, stainless steel sheets, and non-ferrous metal sheets. Thickness typically ranges from 0.4 to 1.5 mm, and the surface is usually treated with coating. Due to variations in material composition and coating quality, service life varies—some can last over 50 years. Sheet shapes differ widely, including composite sheets (where insulation layers are sandwiched between two metal sheets) and single sheets. Installation methods also vary: some are prefabricated in factories and assembled on-site, others are processed directly on-site based on roof requirements. Insulation layers can be pre-composite in factories or fabricated on-site. Therefore, metal sheet roofing systems offer diverse design options suitable for large public buildings, factories, warehouses, residential homes, and more.

5. Sealant Material Waterproofing Workmanship

Sealant materials used in construction refer to substances applied at joints, gaps, door/window frames, glass edges, pipe connections, or other structural interfaces to prevent water and air leakage.

Common sealants fall into two main categories: modified asphalt sealants and polymer-based sealants. Their properties differ significantly, requiring different construction methods. Common techniques include cold-application and hot-application methods.

6. Grouting Material Waterproofing Workmanship

Grouting waterproofing typically involves injecting a liquid prepared from chemical materials into structural cracks under pressure through grout nozzles. After spreading and solidifying, it achieves waterproofing, crack sealing, reinforcement, and strengthening goals. It is commonly used for repairing deep cracks in concrete structures. Based on injection pressure and speed, grouting methods are categorized as high-pressure rapid grouting and low-pressure slow-speed grouting.

1.3.2 Categorized by Whether Heat Application Is Used During Construction

1.Hot Melt Method

Hot melt method refers to the application technique for high-polymer modified asphalt hot-melt membranes. Hot-melt membranes are produced in factories with a soft layer of high melting point modified asphalt on the bottom. During application, no primer is needed; instead, the membrane is directly bonded to the base after heating with a flame gun. This method has minimal environmental impact and relaxed drying requirements for the base surface, though precise temperature control during heating is essential. For roof projects, full-lap or strip-lap methods are used.

2. Cold Adhesive Method

Cold adhesive application typically uses cold-setting adhesives. No heating is required during construction. High-polymer modified asphalt waterproof membranes, especially polymer-based ones, often adopt cold adhesive methods. Oil-based adhesives may also use cold rolling techniques.RollerCold Trowel Application.

During cold adhesive application, the adhesive material is selected based on the membrane's performance. Additionally, the adhesive used at joint areas differs from that used on the base surface. This is because joint adhesives require higher bonding strength, whereas base adhesives can have slightly lower strength. Thus, care must be taken not to mix or misuse them. Adhesive selection is typically specified in the membrane product manual or provided with the material.

Since cold adhesive methods do not require immediate processing of materials like asphalt, they greatly simplify on-site work, reduce environmental pollution, and improve working conditions—making it a highly practical membrane installation method.

For roof projects, cold adhesive application can use full-lap, strip-lap, spot-lap, or spray-lap techniques.

3.Self-Adhesive Method

Self-adhesive membrane application refers to the installation technique for self-adhesive membranes. These membranes are manufactured in factories with a pressure-sensitive adhesive layer or adhesive coating on the bottom, and a release liner on top. During construction, simply peel off the release liner and apply directly. Self-adhesive membranes commonly include high-polymer modified asphalt self-adhesive membranes and polymer-based self-adhesive membranes. Application typically uses full-lap methods. To enhance bonding strength, the base surface should be coated with a primer before application. The membrane should be installed promptly after drying.

4. Lap Joint Method

Lap joint method is applicable only to PVC (polyvinyl chloride) and PE (polyethylene) waterproof membranes. The lap joint process is similar to general polymer membranes, using heat fusion or solvent bonding. There are two types of lap joint techniques: hot-air fusion (hot wind welding), which uses electric heating to generate hot air from the welder, melting the membrane surface to form a bond; and solvent welding (cold welding), which uses solvents (e.g., tetrahydrofuran) for bonding. Lap joint methods include butt joint and abutting joint. Currently, most projects in China use hot-air welding methods.

Composite metal sheet membranes also use lap joint methods—electric heating melts the solder or strips, uniformly covering the joint surface, then cooling to bond the metal sheets together.

1.3.3 Categorized by Application Method of Waterproofing Materials During Construction

1. Spraying Method

Spray application involves placing small-diameter waterproof coatings in a sealed container, then pressurizing them via a centrifugal pump or air compressor to transfer the coating through hoses to the spray nozzle, evenly spraying it onto the base surface to form a uniform, dense waterproof film.

Spraying offers fast speed and high efficiency, especially suitable for various roof surfaces. After spraying, clean equipment such as the sprayer, hose, and container promptly according to the coating type.

2. Troweling Method

Flexible coatings can be applied manually using trowels, long brushes, or round rollers. Troweling is typically done using a flat trowel method, or edge troweling for corners. Apply vertical surfaces first, then horizontal surfaces. For vertical surfaces, flat troweling is recommended. Ensure even, consistent coverage. When troweling, maintain even pressure and avoid over-applying in one area, as this can cause uneven spreading and result in poor surface finish. Do not allow air bubbles to enter the coating layer; if bubbles appear, remove them immediately. Troweling should follow a predetermined pattern and avoid excessive repetition to save time and effort.3. Rolling Method4. Caulking Method

5. Screeding Method

Thick-coating materials are suitable for screeding using a steel trowel or rubber roller. First, evenly spread the coating material directly onto the base surface. Then, use a roller to level and compact the coating, ensuring even thickness, no exposed base, no air bubbles, and a smooth surface. Allow it to dry. For materials with poor leveling ability, use a steel trowel to compact and smooth the surface once the surface moisture evaporates.

5. Sealing Workmanship Sealing workmanship primarily refers to the application of sealant materials. Sealing operations can be categorized into hot-applied and cold-applied methods. Modified asphalt sealants are typically hot-applied, while polymer-based sealants are commonly cold-applied.

Hot-applied sealing requires on-site heating to achieve fluidity before application. This method suits flat joints. Cold-applied sealing mostly uses manual techniques—applying with a trowel or roller. Advanced methods may use electric or hand-held caulking guns.

1.3.4 Categorized by Waterproofing Project Location

1. Roof Waterproofing Projects

Roof waterproofing aims to prevent rainwater from seeping into the interior. Modern requirements extend beyond basic protection to include comprehensive functionality—for example, in sports arenas, parking lots, rooftop gardens, thermal insulation, green roofs, etc.—demanding higher performance from waterproof layers.

2. Bathroom and Basement Waterproofing Projects

Bathroom and basement waterproofing prevents domestic and industrial water, as well as wastewater, from leaking underground or seeping through walls into adjacent rooms. Bathrooms and many industrial workshops have numerous pipes, equipment, and high water usage, often containing acidic or alkaline liquids. Protection against leaks is critical, especially for chemical plants where acid/alkali resistance is essential.

3. Underground Waterproofing Projects

Underground projects refer to industrial and civil underground structures, protective works, municipal pipelines, mountain tunnels, underwater tunnels, reservoirs, underground railways, etc. Underground waterproofing involves design, construction, and maintenance of waterproof systems. Due to complex structures, special construction methods, exposure to surface water, groundwater, and capillary water infiltration, as well as human-induced changes in surrounding soil conditions, underground waterproofing presents greater challenges and higher demands.

4. Water Storage Tanks and Submerged Structures Waterproofing Projects

Water storage tanks and submerged structures waterproofing aims to prevent water or liquid from leaking out and, for underground tanks, to stop groundwater from infiltrating inward. Besides the inherent waterproofing capacity of the tank structure, waterproof layers are usually placed internally. The materials used must not contaminate water quality or be corroded by stored liquids. Many use inorganic materials such as polymer-modified cementitious coatings and water-based waterproof materials.

5. Bridge and Tunnel Waterproofing Projects

With China’s continuous deepening reform and opening-up, infrastructure development has accelerated nationwide. Over the past two decades, major cities like Beijing, Shanghai, Tianjin, and Guangzhou have successively constructed numerous large-scale bridges, overpasses, interchanges, highways, and first-class roads, with annual increases in length exceeding tens of thousands of kilometers. However, many bridges lack proper waterproofing or use unsuitable materials, leading to water infiltration, corrosion of steel bars, peeling of protective layers, alkali-aggregate reactions, and serious damage such as concrete cracking and spalling. These issues severely compromise bridge durability, service life, driving comfort, and safety. Recently, awareness of the importance of bridge and tunnel waterproofing has grown, prompting increasing adoption of integrated waterproofing systems.

6. Exterior Wall Waterproofing Projects

Exterior wall waterproofing prevents rainwater or cleaning water from seeping into indoor spaces. Historically, exterior wall waterproofing has been overlooked compared to roofs, basements, and bathrooms, as infiltration volumes and impacts are smaller. However, as demand for better production and living environments grows, and as infiltration rates from roofs and basements decrease, the importance of exterior wall waterproofing is becoming increasingly evident. China’s research on exterior wall waterproofing is still in its early stages, with many questions remaining: when to implement waterproofing, how to design construction for different structures and wall materials, and how to develop appropriate waterproof materials—all requiring further study and summarization.

In developed countries such as the U.S., Japan, and Western Europe, all bridges are equipped with dedicated waterproof layers. Detailed regulations cover bridge types, surface materials, waterproof technologies, application methods, performance, and maintenance costs. China currently lacks formal guidelines and standards for bridge waterproofing.

国外发达国家，例如美国、日本、西欧诸国对桥梁均设置专门的防水层。从桥梁结构类型、面层材料、防水技术、防水方法、使用性能、维修费用等方面都作了详细的规定，我国尚未有专门的路桥防水施工规范与验收标准。

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Detailed Classification of Waterproofing Engineering! Understand at a Glance!

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