Civil Engineering: Plastering Techniques

Module 3-b: Plastering

• This module covers plastering techniques in civil engineering.
• Students will learn to prepare wall surfaces for plastering, establish correct alignment, determine plaster thickness, and observe proper plastering procedures.
• The module includes a pre-test with questions about wall plastering procedures and the advantages of wetting surfaces before applying mortar.
• Important references are provided including Simplified Building Construction Estimates by Max B. Fajardo Jr. and Estimating Bill of Materials by Tagayun and Associates.

How to Plaster a Concrete Wall

• Plastering is the process of applying mortar to a concrete surface for a smooth finish.
• It acts as a damp-proof layer for brick masonry.
• Critical steps include needing proper materials, tools, and knowledge for plastering a wall.
• Plastering enhances the building's appearance, protects the surface from the atmosphere, covers defective masonry work, and provides a surface for painting.
• Mortar is a mixture of cement and screened sand used for plastering.
• Different types of plaster include lime plaster, cement plaster, stucco plaster, and mud plaster, each with varying properties, such as hardening speed and durability.

Preparing the Wall Surface for Plastering

• Clean wall surfaces, removing oil, grease, etc., with a wire brush.
• Fill cavities or holes in the surface.
• Rake out mortar joints (if necessary), to a depth of at least 12 mm, to improve bonding.
• Wash and keep the mortar joints and entire wall surfaces wet for a minimum of 6 hours before applying cement plaster.
• Remove any projections larger than 12mm to create an even thickness.
• Ensure that the wall's verticality is checked. Use plumb-bobs as needed for correct verticality.

Applying Under-Coat (Base Coat)

• For brick masonry, the base coat is usually 12mm thick.
• For concrete masonry, it can vary from 9 to 15mm.
• A ratio of cement to sand for the first coat of plaster is generally between 1:3 and 1:6.

Applying Finishing Coat

• Second coat (finishing coat) thickness is typically between 2-3 mm.
• The ratio of cement to sand for second coat plaster varies, usually between 1:2 to 1:4.
• Properly damp the first coat before applying the second coat.
• Use appropriate tools like floats and trowels for a smooth, even surface.

Curing of Plastering

• Keeping the plaster wet for 7 days after completion is vital for proper strength and hardness (sprinkling water).
• Gunny bags and other materials can be used for maintaining moisture in plaster in external works.
• Improper curing can lead to cracks and efflorescence (white powdery deposits) in plaster work.
• Curing should start 24 hours after the plaster is laid.

Additional Information

• Video presentations are provided about concrete wall plastering.

Learn plastering techniques for civil engineering, including preparing surfaces, alignment, and thickness determination. Understand how plastering enhances building appearance and protects surfaces. This module references key texts for construction and material estimation.