In today's residential spaces, the underground area is increasingly becoming a part of the living space. Due to the relatively humid underground environment, poor waterproofing can be a real headache. The first step in effective underground waterproofing is choosing the right materials. So, what types of waterproofing materials are used in underground construction? Let Zhaizhong Zhi Zhong introduce you to them.

The basement is often dark, damp, and poorly ventilated, so the waterproofing materials used must meet the following requirements:

1) Excellent moisture resistance and waterproof properties.

2) Strong adhesion to the substrate, excellent durability.

3) Environmental Safety.

Guangzhou's basement waterproofing should adopt a "combining strength and flexibility" composite design, forming a waterproofing layer that achieves "multi-material integration, multiple defense layers, complementary advantages, and long-term effectiveness," thus eliminating future troubles.

1. Cement-based Penetration Crystallization Waterproofing Materials. This type of waterproofing material is rigid and suitable for basements, primarily composed of silicate cement and quartz sand (optional), with active chemicals added to form it. It is categorized into two types based on application methods: cement-based penetration crystallization waterproof coating and cement-based penetration crystallization waterproofing agent. After interacting with water, the active chemicals in the material permeate into the concrete or surrounding areas via a carrier, forming needle-like crystalline bodies that are insoluble in water within the concrete, filling capillary channels, thereby enhancing the density and waterproofing properties of the concrete. The characteristics of cement-based penetration crystallization waterproofing materials include penetration, crystallization, self-healing, and excellent waterproofing performance. The performance of these materials must comply with the mandatory national standard GB 18445-2012 "Cement-based Penetration Crystallization Waterproofing Materials."

Polymer Cement Waterproofing Coating. The polymer cement waterproofing coating, also known as JS waterproofing coating, is a flexible waterproofing material that can also be used in basement waterproofing projects. This coating is primarily made from acrylic, ethylene-vinyl acetate, and other polymer emulsions, along with cement, mixed with fillers and other additives. It solidifies into a film through the evaporation of water and the hydration reaction of cement, forming a two-component water-based waterproofing coating. The liquid component should be a uniform emulsion without impurities or gelling after stirring; the solid component should be a powder without impurities or lumps. JS waterproofing coatings are categorized into Type I, Type II, and Type III, with Type I suitable for substrates with higher movement, and Type II and Type III for those with lower movement. The performance of JS waterproofing coatings should comply with the requirements of GB/T 23445—2009 "Polymer Cement Waterproofing Coating."

Polyurethane Waterproof Coating: Polyurethane waterproof coating is a type of new high polymer waterproofing material that was first developed in Europe, the United States, and Japan in the 1960s. It is a prepolymer containing isocyanate groups, formed by the addition polymerization of isocyanates and polyethers. It is compounded with catalysts, anhydrous additives, anhydrous fillers, solvents, and other ingredients through mixing and other processing steps. It features high strength, excellent elongation, good water resistance, and strong adaptability to substrate deformation, making it suitable for both roof and basement waterproofing.

Polyurethane waterproof coatings are categorized into two-component and one-component types. The two-component polyurethane waterproof coating consists of two components, A and B. Component A is a pre-polymer containing terminal isocyanate groups, made by polymerizing polyether resin and isocyanate, etc., and typically appears as a light yellow, sticky substance; Component B is a paste mixed with hardener, accelerator, toughener, fungicide, filler, and thinner, usually available in red, black, white, yellow, and coffee colors. When using the two-component polyurethane waterproof coating, both components must be weighed and mixed strictly according to the specified ratio, ideally with a mixer. First, mix Component B for 1 to 2 minutes, then pour Component A into the B bucket and mix for 6 to 8 minutes. The mixed material must be used up within 60 minutes. The one-component polyurethane waterproof coating is an amorphous liquid before application and can be used directly without on-site mixing. During application, use the layer-by-layer painting method, typically requiring 2 to 3 layers. After each layer is applied, allow the coating film to cure fully, with an interval of about 12 hours between coats, based on not sticking to the foot. The direction of each coat should be perpendicular to the previous one.

It's important to note that basements are typically dark and damp, with the subfloor taking longer to dry. Therefore, it's advisable to use materials suitable for installation on damp subfloors. Additionally, due to poor ventilation in basements, for environmental protection and safety reasons, it's best to opt for eco-friendly polyurethane waterproof coatings.