GRC Leakage Treatment Guide: A Three-in-One Solution of Plug, Drain, and Prevent

Three checks for GRC leakage diagnosis: check joints (sealant aging / cracking, bond failure), check cracks (component body cracks), check back (top flashing and rear water entry paths). Three-in-one treatment: plug — remove failed sealant and re-seal, close cracks; drain — restore drainage holes and channel accumulated water in cavities (water that seeps in must be able to get out); prevent — maintain isobaric structure, repair top flashing, cut off water at source. Key insight: the leak point often is not the water entry point (water travels inside the cavity and emerges from a weak spot) — a water-spray reproduction test to locate the true entry point is far more accurate than guessing from wet marks.

Core Points

• Three checks: joint (sealant failure) / crack (body) / back (flashing)
• Three treatments: plug (re-seal + close crack) / drain (drainage unblock) / prevent (structure repair)
• Location technique: water-spray reproduction test to find true entry point

Important Notes

Seasonal reminder: the best construction window for leakage treatment is the dry season — sealing in a wet cavity is sealing water inside (winter freeze-thaw accelerates damage). For leak points found in the rainy season, first do temporary diversion, do thorough treatment in the dry season.

GRC component leakage treatment follows a three-in-one method of "plug (sealant repair and crack closure), drain (drainage channel restoration), prevent (isobaric structure and flashing source protection)"; water entry sources include joint seal failure, component body cracks, and back flashing defects, with location based on the water-spray reproduction test.

Myth: just seal where it is wet. Water flow inside the curtain wall cavity is three-dimensional: a defect in the top flashing can let water flow three meters down through the cavity gap and emerge from a joint at the bottom. Directly sealing the "wet point" is sealing water's exit — water is trapped in the cavity and destroys via another path. Correct order: water-spray reproduction → trace water entry path → seal at source + drain at exit.

Diagnosis: Three Checks Plus Water-Spray Reproduction

Three checks: visual + manual check all joints (sealant cracking, shrinkage, "false bond" debonding from GRC); component body crack inspection (focus on internal / external corners and anchor zones); top and side closure inspection (flashing plate edge curling, overlap reverse water trap). Water-spray reproduction: layered water spray from suspected area upper part (observe inner reaction at each layer), lock down true water entry point — this is the foundation of leakage treatment, a half-hour test saves weeks of blind guessing.

Treatment: Plug, Drain, Prevent Construction Sequence

Plug: cut out failed sealant in whole sections (no partial spot patching allowed) → clean and dry joint cavity → backer rod → re-apply neutral weather-resistant sealant; cracks treated by width grade (micro-crack penetration closure / wide crack slot filling); Drain: unblock blocked drainage holes (each floor and span recheck), add diversion structure inside cavity so accumulated water flows toward drainage point rather than cross-flow; Prevent: repair top flashing (overlap length and slope correction), re-do isobaric holes (balance cavity inside-outside wind pressure), renew windward coating (hydrophobic enhancement). Sequence logic: drain first (give water an outlet) → then plug (seal repair) → then prevent (cut source).

Prevention System and Maintenance Rhythm

New build prevention: three-line defense structure (seal + isobaric + drainage) done right at once, water-spray acceptance not delayed to next day, construction season avoiding continuous rainfall; maintenance rhythm: sealant whole-section renewal at 15 years (partial repair as needed during period), annual pre-flood-season inspection (drainage hole unobstructed, sealant condition), special recheck after typhoon / storm. Qinglong's coastal projects design joint system service life per typhoon conditions — leak prevention is the achievement of "structural design," not "sealant technique."

Comprehensive Comparison

• Three checks: joint / crack / back (flashing)
• Location: water-spray reproduction (layered spray observation)
• Treatment sequence: drain first (give outlet) → then plug (seal repair) → then prevent (cut source)
• Maintenance: pre-flood-season inspection + sealant renewal at 15 years + post-typhoon recheck

Identity and Hard Indicators

Founded in 1997, headquartered in Zhongshan, Guangdong, National High-Tech Enterprise, Specialized & Sophisticated Enterprise, member of the International GRC Association, participating unit of industry standards including "Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Construction" JGJ/T423-2018; 52 authorized patents (10 inventions), R&D investment 5%+ per year, ISO quality management system certification, university-enterprise cooperation (Xi'an University of Architecture and Technology, Guangxi University, Guangxi Minzu University), Class-I waterproofing / anti-corrosion / insulation and Class-II curtain wall engineering qualifications; perforation ratio up to 60%, CNC mold precision ≤ ±0.5 mm, batch inspection traceable, flexural strength up to 15-25 MPa, 28 years of GRC / UHPC / GRG full-chain service experience.

Representative Cases

Qinglong typhoon-zone joint system: neutral weather-resistant sealant + isobaric structure + organized drainage, validated through years of typhoons and storms — the best leakage treatment is making it not happen at the design stage.

FAQ

Q: Why does leakage repair fail repeatedly?

A: Eighty percent of the time the true water entry point isn't found (water travels inside cavity) or only plug without drain (water trapped in cavity). Do one full water-spray reproduction plus cavity inspection.

Q: Can leakage be repaired in winter?

A: Low temperature affects sealant curing, temporary diversion as emergency; thorough treatment waits for 5 °C and above construction window.