This guide explains how underslab waterproofing membranes protect foundations from hydrostatic pressure, capillary moisture, and vapor transmission in below-grade construction. It compares pre-applied HDPE sheets, bentonite systems, fluid-applied membranes, and composite technologies while outlining key selection factors such as concrete bonding, puncture resistance, soil chemistry, and site conditions. Readers will also learn how drainage, substrate preparation, penetration detailing, dewatering, and pre-pour QA/QC affect long-term performance, helping architects, engineers, and contractors select reliable sub-slab water protection systems for foundations and other below-grade structures.
Below-grade waterproofing systems protect foundations and underslabs from groundwater, hydrostatic pressure, and moisture intrusion. This guide explains how to evaluate site conditions and choose between pre-applied membranes, bentonite systems, polymeric barriers, and integral concrete waterproofing. It also covers drainage design, critical transitions, substrate preparation, penetration detailing, construction protection, quality assurance, and project sequencing. Contractors, engineers, and specifiers can use these practical guidelines to select the right foundation waterproofing solution, reduce installation risks, and create a durable barrier against long-term below-grade water ingress.
This guide explains how concrete foundation waterproofing protects below-grade structures from groundwater, hydrostatic pressure, capillary moisture, and long-term deterioration. It compares dampproofing with true waterproofing, evaluates exterior membranes and interior drainage systems, and explains how drainage boards, sump pumps, sealants, and crack injection technologies work together. The article also covers new construction versus retrofit projects, material compatibility, surface preparation, and common installation risks. Property owners, contractors, and facility managers can use these insights to select a practical waterproofing strategy and improve the long-term durability of concrete foundations.
Aging and failure of the waterproofing layer on the roofs of urban residential buildings is a common problem, especially for flat roofs using bitumen-based waterproofing membranes (such as SBS and APP). After long-term exposure to sun and rain, and thermal expansion and contraction, these roofs are prone to cracking, hollowing, and leakage. To address this issue, Canlon Repair, a subsidiary of Canlon Group, can provide customized system solutions to create a waterproof barrier for your building.
On June 5, 2026, Canlon was granted an invention patent, "A Test Device for a Siphon Drainage System of a Membrane Metal Roofing", patent number ZL202311789137.5. This marks the formal integration of "active drainage" into the core capability of the membrane metal roofing (Fusion® integrated panel) system, in addition to "waterproofing"—the "integrated waterproofing and drainage" concept has moved from a theoretical concept to a testable and verifiable engineering practice.
The National Building Standard Design Atlas 25J950, "Building Waterproofing," is an important guide for professionals in the building waterproofing industry. It provides detailed descriptions of waterproofing projects for metal roof panels and polymer membrane metal composite profiled sheet roofs, offering a unified and scientific technical reference for the Chinese building waterproofing industry. In the compilation of this national standard atlas, Canlon not only contributed its waterproofing expertise as a participating unit, but the technical standards for its representative innovative product—the polymer membrane metal composite profiled sheet system—were also included in Chapter 10. Let's take a look at the relevant content.
In 2021, CCTV's "News Broadcast" featured a special report on a benchmark urban renewal project—the Taizhou Old City Renovation Project in Zhejiang Province. The video showcased the Taizhou Jiaojiang Bridge East Project, constructed by Greentown Leju, as a model, demonstrating how the living environment of residents in the old city area has been improved. This project is one of Canlon's representative works in the "urban renewal" journey. Taizhou's old city area suffers from numerous dilapidated and unsafe buildings, prompting residents to yearn for relocation to new homes. Taizhou City Development Group, Greentown Construction Management, and Fangyuan Construction, the general contractor, all possess high-quality resources from front-end planning and design to back-end property management. Supported by robust product and management standards, they have accumulated extensive resources covering the entire industry chain.
The roof is the part of the building envelope most directly affected by the external environment. The design of its waterproofing and insulation system directly determines the building's durability and energy efficiency. Based on the relative positions of the waterproofing layer and the insulation layer, flat roof projects can be divided into three basic types: upright, inverted, and sandwich. Understanding the principles and applicable conditions of these three structural systems is fundamental to roof project design.
Recently, Typhoon "White Dolphin," the 11th typhoon of the year, made landfall twice along the coast of Zhejiang Province, bringing torrential rains and gale-force winds as it moved northward. Its impact extended across Zhejiang, Shanghai, Jiangsu, Anhui, Hubei, Henan, Hebei, and beyond. Meteorological forecasts indicate that after its remnant system combines with cold air, the Beijing-Tianjin-Hebei region and Liaoning will also experience significant rainfall. Typhoons test not only a city's drainage infrastructure but also push building roofing systems to their limits. Intense rainfall combined with instantaneous gale-force winds subjects roofs to immense water pressure and powerful wind uplift forces equivalent to a Category 17 super typhoon—any weak link can lead to leakage or even structural failure. In this extreme weather challenge, Canlon's polymer waterproofing systems delivered a performance that stands up to scrutiny.