Overview:

A scratch coat, also known as “Tartasha” in Arabic, is the first rough plastering layer applied to walls and ceilings before the final finishing coat. This layer provides a textured surface to enhance adhesion for subsequent layers, ensuring durability and long-lasting plasterwork. It is commonly used in masonry, concrete, and blockwork applications.


Why You Should Use It:

  • Enhances Adhesion: Creates a rough base for the finishing coat.
  • Prevents Cracks: Reduces shrinkage and structural cracks in plaster.
  • Durable & Strong: Increases the longevity of the plaster system.
  • Weather Resistant: Protects against environmental damage.
  • Improves Load Distribution: Helps evenly distribute stress across walls.

Key Features:

PropertyDescription
Material CompositionCement, sand, and water
Application Thickness5–10 mm
Texture TypeRough and uneven
Drying Time24–48 hours before applying the next coat
Bonding StrengthHigh adhesion for better plaster durability

Uses:

  • Base Layer for Plastering: Prepares the surface for the final smooth coat.
  • Masonry & Concrete Walls: Enhances plaster adhesion to rough surfaces.
  • Ceiling Coating: Ensures plaster sticks properly on ceilings.
  • Exterior Wall Coating: Provides additional protection against moisture.
  • Renovation Projects: Improves adhesion in restoration works.

Density & Composition:

FactorValue
Density1600–1800 kg/m³
Cement Content1:2 or 1:3 (cement to sand ratio)
Water AbsorptionMedium, allowing better bonding

Case Studies:

  1. Residential Buildings: Used in luxury villas for crack-resistant walls.
  2. Commercial Complexes: Applied in high-rise structures for durability.
  3. Historical Renovations: Used to restore and reinforce old buildings.

Application Recommendations:

  • Use Proper Mixing Ratio: 1 part cement to 2 or 3 parts sand for best results.
  • Keep Surface Moist: Dampen the surface before application for better adhesion.
  • Use a Notched Trowel: Creates grooves to improve mechanical bonding.
  • Allow Proper Curing: Keep the scratch coat moist for at least 3 days.

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