Cement Plastering Works Procedures in Qatar requires adherence to specific procedures to ensure high-quality finishes suitable for the local climate and conditions. Here’s a detailed step-by-step guide to the procedure for cement plastering works in Qatar:
1. Preparation
a. Material Selection
- Cement: Use Ordinary Portland Cement (OPC) or sulfate-resistant cement for areas exposed to sulfates.
- Sand: Clean, well-graded, and free from impurities.
- Water: Clean, potable water free from salts and organic matter.
- Admixtures: Use as per the project requirements (e.g., waterproofing agents, plasticizers).
b. Surface Preparation
- Cleaning: Remove dust, loose materials, and contaminants from the surface.
- Repair: Patch cracks, holes, and imperfections.
- Dampening: Moisten the surface to prevent water from being absorbed too quickly from the plaster.
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2. Mixing
a. Proportions
- Common ratio: 1:4 (cement to sand) for general plaster.
- For undercoat: 1:3 or as specified.
- For finish coat: 1:5 or as specified.
b. Mixing Method
- Use mechanical mixers for consistency.
- Mix dry components first, then add water slowly until the desired consistency is achieved.
3. Application
a. Undercoat
- Scratch Coat:
- Apply a rough first coat to improve the bond.
- Thickness: 10-15 mm.
- Allow to cure for 24 hours before applying the brown coat.
- Brown Coat:
- Apply over the scratch coat to level the surface.
- Thickness: 6-10 mm.
- Ensure an even and uniform surface.
b. Finish Coat
- Apply a thin, smooth coat (2-3 mm) after the undercoat has cured.
- Use a steel trowel to achieve the desired texture and smoothness.
- For decorative finishes, use appropriate tools or patterns.
4. Curing
- Water Curing: Keep the plaster moist for at least 7 days to achieve optimal strength.
- Curing Compounds: Use if water curing is not feasible.
5. Quality Control
- Check Surface Regularity: Ensure no cracks, voids, or bulges.
- Thickness Verification: Use gauges or rulers to ensure consistent thickness.
- Adhesion Test: Ensure the plaster adheres properly to the substrate.
- Finish Inspection: Verify the smoothness and appearance of the finished surface.
6. Health and Safety
- Personal Protective Equipment (PPE): Workers should wear gloves, masks, and goggles.
- Ventilation: Ensure good ventilation in enclosed areas to avoid dust accumulation.
- Handling Materials: Follow safety guidelines for handling cement and other materials.
7. Environmental Considerations
- Waste Management: Dispose of plaster waste and debris according to local regulations.
- Dust Control: Minimize dust generation by using wet cutting methods and proper containment.
8. Compliance with Standards
- Local Standards: Follow Qatar Construction Specifications (QCS) for plastering works.
- International Standards: Adhere to relevant ISO and ASTM standards for materials and methods.
Tools and Equipment Needed
- Tools: Trowels, hawks, floats, straight edges, plumb bobs, spirit levels.
- Equipment: Mechanical mixers, scaffolding, water hoses, curing blankets.
Notes:
- Temperature and Humidity: Be mindful of Qatar’s high temperatures and humidity levels. Avoid plastering in extreme heat or direct sunlight; protect the plastered surfaces from rapid drying and excessive moisture.
- Plaster Type: Consider the use of specialized plasters for exterior applications or areas exposed to harsh environmental conditions.
Following these detailed steps will ensure that cement plastering works are carried out effectively and to a high standard, suitable for the specific requirements of Qatar’s construction environment.