Module 7: Building Technology – Damp, Ventilation, Drainage, and Sustainable Bricklaying

1. Understanding Damp and Ventilation in Masonry

Dampness in masonry is a common issue that can compromise structural integrity and indoor air quality. Proper ventilation is essential to prevent moisture accumulation.

• Types of Damp:

  • Rising Damp: Occurs when groundwater moves upward through porous bricks and mortar due to capillary action. A damp-proof course (DPC) is required to prevent this.

  • Penetrating Damp: Caused by water seeping through walls from external sources (e.g., rain, faulty gutters). Proper waterproofing and cavity walls help mitigate this.

  • Condensation Damp: Results from high humidity levels inside buildings, leading to moisture buildup on cold surfaces. Adequate ventilation reduces condensation risks.

• Ventilation Solutions:

  • Air Bricks & Vents: Allow airflow within cavity walls and sub-floor spaces to prevent moisture buildup.

  • Mechanical Ventilation: Extractor fans in high-humidity areas (e.g., kitchens, bathrooms) help expel moist air.

  • Breathable Materials: Using lime mortar instead of cement improves moisture evaporation from walls.

2. Basic Drainage Principles for Brickwork (e.g., Gullies)

Proper drainage is crucial to direct water away from brick structures, preventing erosion and dampness.

• Gullies and Drainage Systems:

  • Gullies: Shallow channels or drains collect surface water and direct it to sewers or soakaways. They prevent water pooling near foundations.

  • Weep Holes: Small openings in brickwork (especially in retaining walls) allow trapped water to escape.

  • Slope and Grading: Ground around buildings should slope away (minimum 1:20 gradient) to ensure water runoff.

• Damp-Proofing Measures:

  • Cavity Wall Construction: Creates a gap between inner and outer brick layers, preventing moisture transfer.

  • French Drains: Perforated pipes surrounded by gravel help divert groundwater away from foundations.

3. Introduction to Sustainable Bricklaying Practices

Sustainable bricklaying minimizes environmental impact while maintaining durability and efficiency.

• Eco-Friendly Materials:

  • Recycled Bricks: Reusing bricks from demolished structures reduces waste and carbon footprint.

  • Low-Carbon Bricks: Innovations like hempcrete or compressed earth blocks offer sustainable alternatives.

  • Lime Mortar: More environmentally friendly than cement, as it absorbs CO₂ over time and allows for easier recycling.

• Energy-Efficient Techniques:

  • Thermal Mass Utilization: Brick’s natural heat retention reduces reliance on artificial heating/cooling.

  • Insulated Cavity Walls: Improves energy efficiency by reducing heat loss.

• Waste Reduction Strategies:

  • Precision Cutting: Minimizes brick wastage during construction.

  • Modular Design: Standardized brick sizes reduce offcuts and excess material use.

By integrating proper damp prevention, effective drainage, and sustainable practices, masonry structures can achieve longevity, energy efficiency, and environmental responsibility.