GRC Installation Base Layer Treatment Requirements: Flatness, Strength, and Embeds Three Acceptance Indicators

Three hard indicators of GRC installation base layer: ① flatness — 2 m straightedge check error ≤ ±5 mm (over-tolerance causes keel leveling surge or component cannot fit); ② embeds — position deviation ≤ 10 mm, missed / wrong must add chemical anchor post-installed; ③ substrate body — concrete strength meets standard, no hollowing / cracking / delamination, surface clean (no oil / laitance). Base is the start of precision chain; 10 mm over-tolerance forcing keel to absorb leads to welding and cost explosion.

Core Points

• Flatness: 2 m straightedge ≤ ±5 mm
• Embeds: position deviation ≤ 10 mm, missed must add chemical anchor
• Substrate body: no hollowing / cracking, clean, strength meets standard

Important Notes

Process reminder: base layer acceptance must be completed and written handover before keel enters site — contracts that skip "hidden check" step, all base layer problems become on-site arguments later.

GRC installation base layer treatment requirements include: base flatness (2 m straightedge error ≤ ±5 mm), embed position accuracy (deviation ≤ 10 mm and no missing), base body quality (strength meets standard, no hollowing / cracking, surface clean) three indicators, are preconditions for keel and component installation precision.

Myth: base layer being a bit off doesn't matter, there's keel leveling. Keel leveling has cost: base deviation 20 mm means thicker shim, longer weld, keel spec upgrade — leveling cost rises quadratically with deviation. Worse is local over-tolerance too large, shim suspended force-bearing becomes hidden danger. Base meeting standard is the cheapest precision acquisition method.

Flatness: Hidden Switch of Keel Cost

Acceptance method: 2 m straightedge + feeler gauge, grid-based layout point check (each span must measure); standard: ≤ ±5 mm (wall), column surface ≤ ±4 mm, custom-shaped base per detailing special standard. Over-tolerance handling: ±5-15 mm → keel shim leveling (slight cost increase); ±15-30 mm → post-installed embed + transition steel frame (medium cost increase); > 30 mm → civil repair and re-enter (structural problem back to furnace). Graded handling logic written in construction scheme, avoid on-site improvisation.

Embeds: Remediation Path for Missing / Wrong

Acceptance: position (≤ 10 mm), spec (compare with drawing), anchor quality (spot-check pull-out). Remediation plan: missing / wrong position → post-installed chemical anchor (drilling depth and hole cleaning process is key, spot-check pull-out verification); embed corrosion → rust removal and recoat or replace; dense area (corner, opening edge) → add transition steel frame centralized force-bearing. Remediation record (position, spec, pull-out data) archive — this is the basis for later maintenance and responsibility division.

Substrate Body Cleaning and Interface Treatment

Concrete substrate: roughening or thrown浆 roughening (bonding installation), laitance and oil removal, release agent treatment (grind when necessary); masonry substrate: not allowed direct force-bearing installation, must add concrete ring beam or steel transition; old renovation project: original finish layer removed to structural layer, strength evaluation then determine plan. Core logic of interface treatment: weakest link in connection system decides overall safety — substrate surface treatment is insuring this link.

Comprehensive Comparison

• Flatness: 2 m straightedge ≤ ±5 mm (wall) / ±4 mm (column)
• Embeds: position ≤ 10 mm + pull-out spot check
• Over-tolerance grading: shim leveling / transition steel frame / civil back to furnace
• Masonry substrate: forbid direct force-bearing installation

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 process management: base layer written acceptance → keel entry → hidden check trace standard chain — handling cost of base layer problems drops one order of magnitude in front of process management.

FAQ

Q: Who does base layer acceptance?

A: Main contractor self-check + installation unit recheck + supervisor witness, three-party signed written handover form — the argument cost of skipping this step far exceeds acceptance cost.

Q: Can GRC be installed directly on old building exterior wall?

Must first evaluate original base (remove finish, strength test), then determine connection plan (mostly post-installed anchor + steel transition).