1
Project Overview
The first phase of a Guizhou winery project is located in Huichuan District, Zunyi City. The project occupies an additional 350 mu (233,000 m2) of land and will include a winemaking workshop, a large and small koji making workshop, a wine cellar, a tank warehouse, a blending workshop, a packaging center (including a bottle warehouse, a packaging material warehouse, and a finished product warehouse), a power distribution and maintenance room, a boiler room, a high-level water tank, a sewage treatment plant, and roads. Upon completion, the project will add 15,000 tons/year of production capacity. Due to the region's annual rainfall exceeding 1,100 mm and the large amount of winemaking equipment and raw materials within the factory, the area is highly susceptible to roof leakage. In accordance with the relevant provisions of the "General Code for Waterproofing of Buildings and Municipal Engineering" (GB 55030-2023), the project's waterproofing environment category is Class II, the project's waterproofing category is Class A, and the roof waterproofing protection level requirement is Class I.
2
Waterproofing Design and Material Selection
2.1
Waterproofing Design
The roof structure of this project, from top to bottom, is as follows: 40 mm thick fine aggregate concrete protective layer → 10 mm thick low-grade mortar isolation layer → 1.6 mm thick butyl self-adhesive polymer waterproofing membrane (TPO) → 1.5 mm thick polymer cement waterproofing coating → 30 mm thick fine aggregate concrete leveling layer → 50 mm thick extruded polystyrene insulation board → 1.5 mm thick non-asphalt-based strong cross-membrane self-adhesive waterproofing membrane → reinforced concrete roof slab (structurally graded, smoothed and calendered). See Figure
1.
Figure 1 Roof structure layers
2.2
Waterproofing Design Discussion
The roof waterproofing approach for this project was determined based on the "General Specification for Waterproofing of Buildings and Municipal Engineering" (GB 55030-2022) and other factors, including the on-site construction environment.
According to the General Specification for Waterproofing, flat roofing projects must have at least three waterproof layers at the first level. Waterproofing layers can be made of waterproof membranes or waterproof coatings, and at least one waterproof membrane layer should be used.
The project site is humid with year-round rainfall, and the roof is susceptible to deformation and cracking due to temperature fluctuations. To ensure the quality of the waterproofing and meet the construction schedule, a design was adopted in which the waterproof layers were located above and below the insulation layer. This design combines the advantages of both upright and inverted roofing:
1) A non-asphalt-based, strong, cross-membrane self-adhesive waterproofing membrane was applied to the roof structure, providing full adhesion and water-proofing. This not only reduces the risk of leakage during construction interruptions, but also effectively prevents rainwater from seeping in after the upper waterproofing layer fails, potentially impacting the building structure and normal use. In addition, it also acts as a vapor barrier. This project primarily involves winemaking workshops, where significant amounts of water vapor are generated during each production process. This waterproof membrane effectively prevents indoor water vapor from rising through the roof panels and entering the insulation layer.
2) Designing and constructing two waterproof layers on the insulation layer: a polymer cement waterproof coating and a butyl self-adhesive polymer waterproof membrane (TPO). Combining the respective characteristics of the waterproof coating and the waterproof membrane, and leveraging their strengths, this can better prevent rainwater from entering the insulation layer and causing adverse effects, thereby improving project quality.
2.3
Material Selection and Advantages Analysis
When selecting waterproofing materials, it's important to consider not only the building type and intended use, but also the local climate and environmental factors. Selecting materials suitable for the waterproofing requirements of the roof area ensures effective waterproofing. This project primarily utilizes polymer waterproof membranes and water-based waterproof coatings, which offer excellent environmental performance, strong environmental adaptability, and a highly compatible waterproof layer. 2.3.1 Non-Asphalt-Based Strong Cross-Laminated Self-Adhesive Waterproofing Membrane
Non-Asphalt-Based Strong Cross-Laminated Self-Adhesive Waterproofing Membrane is a self-adhesive waterproofing membrane composed primarily of a non-asphalt self-adhesive polymer resin (C9 resin) and ultra-high molecular weight rubber, combined with a two-color strong cross-laminated membrane. This product uses no asphalt and offers stable and reliable performance. It emits no irritating odor during production and application, and features outstanding adhesion, water resistance, and excellent aging resistance. This membrane can be applied using either dry or wet layup techniques, depending on the substrate and environment. The wet layup technique requires a lower substrate moisture content, making installation convenient and quick.
2.3.2 Polymer Cement Waterproofing Coating + Butyl Self-Adhesive Polymer Waterproofing Membrane (TPO)
The coating waterproofing layer exhibits excellent integrity, fully adhering to the substrate and forming a continuous, seamless waterproof layer. Compared to waterproofing membranes, it is more convenient and easier to identify, measure, and maintain leaks. The waterproofing membrane has a uniform thickness, making its construction less susceptible to environmental influences. It exhibits excellent tensile strength, weather resistance, heat resistance, and low-temperature flexibility. However, the reliability of the overlapped edges and the sealing of the finished edges are highly dependent on the quality of on-site construction.
The project utilizes a polymer cement waterproofing coating combined with a butyl self-adhesive polymer waterproofing membrane (TPO) over the insulation and leveling layers. The thick-coat polymer cement waterproofing coating exhibits superior crack resistance compared to conventional polymer cement waterproofing coatings. During application, the number of application passes can be reduced for the same design thickness, effectively saving labor and time. It also reduces cracking problems caused by excessive coating buildup during detailed construction. Polymer cement waterproofing coating is a water-based coating that produces no harmful gases during mixing and application. It is environmentally friendly and has low substrate requirements. It can be applied even on damp but dry surfaces. It also exhibits excellent compatibility with various self-adhesive membranes and provides excellent adhesion, forming a reliable and effective waterproofing layer.
The butyl self-adhesive polymer waterproofing membrane (TPO) used in this project is primarily constructed from 1.2 mm thick thermoplastic polyolefin sheets, with a butyl self-adhesive adhesive thickness of 0.4 mm. Compared to asphalt membranes, this membrane is more environmentally friendly and offers superior physical properties. The plastic reinforcement provides enhanced corrosion resistance and physical root barrier properties, resolving the issue of peeling after brief exposure, sun exposure, or soaking in water. It achieves a skin-like, full bond to the substrate, preventing water leakage. The overlapped edges are welded, ensuring stable and reliable performance, effectively reducing the risk of peeling and warping.
3
Construction Process
Non-asphalt-based strong cross-membrane self-adhesive waterproofing membrane construction process: Cleaning the base layer → Strengthening detailed joints → Laying the non-asphalt-based strong cross-membrane self-adhesive waterproofing membrane → Overlapping membrane joints → Fixing and pressing edges → Self-inspection, repair, and acceptance.
Polymer cement waterproofing coating + butyl self-adhesive polymer waterproofing membrane (TPO) composite waterproofing layer construction process: Cleaning the base layer → Preparing the polymer cement waterproofing coating → Strengthening detailed joints → Applying waterproofing coating to the main surface → Self-inspection, repair, and acceptance → Pre-laying the membrane → Laying the butyl self-adhesive polymer waterproofing membrane (TPO) → Overlapping membrane joints → Fixing and pressing edges → Self-inspection, repair, and acceptance. 3.1
Substrate Preparation
Remove any debris, oil, sand, protruding stones, or mortar lumps from the substrate surface. Repair any cracks with waterproof mortar. Round the intersections of horizontal and vertical surfaces, as well as corners, to ensure a solid substrate free of hollows, sand, cracks, looseness, or unevenness. Avoid any visible water.
3.2
Detailed Joint Treatment
Both non-asphalt-based strong cross-membrane self-adhesive waterproofing membranes and roll-applied composite waterproofing layers require an additional waterproofing layer. Non-asphalt-based strong cross-membrane self-adhesive waterproofing membranes use a homogeneous membrane as the additional waterproofing layer, while roll-applied composite waterproofing layers use a thick-coat polymer cement waterproofing coating as the additional waterproofing layer.
1) Treatment of Corners and Pipe Root Joints
An additional layer of paint should be applied to corners, pipe roots, and other special areas (first apply a single coat of paint, then apply a 40 g/m² non-woven fabric as reinforcement. Finally, apply two coats of paint to completely saturate the non-woven fabric. No exposed non-woven fabric should be exposed, and no wrinkles should occur). The additional layer should be 250 mm wide on both horizontal and vertical surfaces.
2) Treatment of Parapet Joints
Each waterproofing layer should be applied first, with a 500 mm wide additional waterproofing layer (250 mm wide on both horizontal and vertical surfaces), before the large-surface waterproofing layer is applied. Since all parapets on site are high, the large-surface waterproofing layer should be extended no less than 250 mm above the finished roof surface. It should be secured with a sealing strip and reinforced with sealing material (Figure 2).
Figure 2 Parapet node processing
3) Expansion Joint Treatment
First, prepare the base surface surrounding the expansion joint. The base surface should be clean, flat, and solid, and the inside corners should be smoothed to rounded shapes. Clean the expansion joint gaps to ensure they are free of debris or other debris. Fill the gaps with insulation and sealing material. Apply a non-asphalt-based, strong, cross-membrane, self-adhesive waterproofing membrane and fold it up to the top of the expansion joint. Cover the top with a hollow layer of membrane for reinforcement, and place foam rods in the middle. After the large-surface insulation and leveling layer are completed, apply a composite waterproofing layer, folding it up to cover the expansion joint. Finally, apply a protective layer on top of the expansion joint, followed by a cement mortar protective layer and a concrete cover plate (Figure 3).
Figure 3 Deformation joint node processing
4) Downspout Node Treatment
First, prepare the base surface surrounding the downspout. Then, apply a non-asphalt-based, strong, cross-membrane, self-adhesive waterproofing membrane to the edge of the downspout and reinforce it with sealing material. After the main surface is completed, apply a composite waterproofing layer over the insulation leveling layer. The waterproofing layer must be sealed within the rain gutter and reinforced with sealing material in the rain gutter and surrounding areas (Figure 4).
Figure 4 Drainage outlet node processing
3.3
Large Surface Waterproofing Construction
1) Large Surface Waterproofing with Non-Asphalt-Based Strong Cross-Membrane Self-Adhesive Waterproofing Membrane: During large-surface application, the barrier film can be removed to ensure full adhesion of the membrane. During the installation process, pressure and air should be released as the membrane is laid. The short-side overlap should be staggered by at least 500 mm. The long-side overlaps of the membrane are designed with an anti-contamination barrier film to prevent contamination during large-surface application. The barrier film can be removed after the large-surface application is completed, ensuring the membrane's overlap is intact.
2) Large Surface Waterproofing with Polymer Cement Waterproofing Coating + Butyl Self-Adhesive Polymer Waterproofing Membrane (TPO) Composite Waterproofing Coating: The composite waterproofing layer should be applied first, followed by the membrane. For polymer cement waterproofing coating, thoroughly mix the powder and liquid materials according to the proper ratio. Apply the coating in multiple thin coats to the desired thickness. The second coat should be applied after the first coat has dried, with the two coats perpendicular to each other. The coating should be used before it sets. Wait until the paint is completely dry before laying the membrane. Before laying the membrane, use a line marker to mark the position and pre-lay the membrane to release the prestress of the membrane when it is rewound. The waterproof membrane and paint can be directly bonded, without the need for a base treatment agent. First, secure the end of the membrane, gently cut open the large-surface membrane isolation film with a paper cutter, and then lay the self-adhesive membrane. While one worker lays the membrane, another worker uses a pressure roller to roll the membrane vertically from one side of the long side to the other to release air, so that the membrane and the base layer are firmly bonded until one membrane is laid. When laying the second membrane, pre-lay the membrane and align it with the overlap guide line of the first membrane, ensuring that the overlap width is no less than 80 mm. The laying method is the same as for the first membrane, and ensure that the overlap seams of the short sides of the two adjacent membranes are staggered by no less than 500 mm. The overlapping edges are welded using hot air welding, with an 80 mm overlap width for both long and short sides. Long overlaps are welded using an automatic welding machine, while short overlaps are welded using a dedicated 160 mm wide butt welding strip and a handheld welding torch.
3.4
Self-Inspection, Repair, and Acceptance
After each waterproofing layer is completed, a self-inspection is conducted. Any damaged areas are repaired promptly, and then a unified acceptance inspection is conducted. Only after passing the acceptance inspection can the next step be carried out.
4
Conclusion
The "General Specification for Waterproofing of Buildings and Municipal Engineering" stipulates that the design service life of roofing waterproofing projects must be no less than 20 years. The selection and combination of materials for the first-level three waterproofing layers are crucial to ensuring the waterproofing effectiveness and durability of the project. The roof waterproofing of this project is based on the requirements of the specifications and the application scenarios. The three waterproof layers are set as a sandwich structure. The first waterproof layer plays the role of waterproofing and vapor isolation. The last two waterproof layers fully demonstrate the advantages of the roll-coated composite waterproof layer. Combined with the excellent physical and chemical properties of the polymer roll material itself and the excellent adaptability and environmental protection of water-based coatings, it provides a reliable solution for roof waterproofing projects and also provides a reference for the design and construction of similar projects.
