Roofs & Roof Coverings
In building construction, the roof is a vital structural element that provides protection against environmental conditions such as rain, sun, wind, and temperature variations. The study of Roofs & Roof Coverings is an important part of ITI Draughtsman Civil, as it helps students understand the design, types, and materials used in roofing systems.
1. Definition of Roof
A roof is the topmost covering of a building that protects the structure and its occupants from weather effects. It is supported by walls, beams, or columns and is designed to transfer loads safely to the foundation.
2. Requirements of a Good Roof
- Strength to carry dead load and live load.
- Resistance to weather conditions like rain, heat, and wind.
- Proper drainage system for rainwater.
- Durability and low maintenance.
- Thermal insulation and sound insulation.
- Fire resistance and safety.
3. Types of Roofs
(a) Flat Roof
- Almost horizontal surface with slight slope.
- Commonly used in residential buildings.
- Can be used as terrace or for additional activities.
- Constructed using RCC or reinforced brick.
(b) Pitched Roof
- Inclined or sloping roof.
- Suitable for areas with heavy rainfall or snowfall.
- Constructed using timber or steel trusses.
(c) Curved Roof
- Has a curved shape for aesthetic and functional purposes.
- Used in auditoriums, sheds, and special buildings.
(d) Shell Roof
- Thin RCC structure with curved surface.
- Suitable for large span structures.
4. Roof Coverings
Roof covering is the outermost layer placed over the roof structure to protect it from weather conditions. It also enhances the appearance and durability of the building.
Types of Roof Coverings
(a) Thatch Roofing
- Made from dry grass, straw, or palm leaves.
- Used in rural and temporary structures.
- Low cost but less durable.
(b) Tile Roofing
- Uses clay or concrete tiles.
- Provides good insulation and attractive appearance.
- Common in pitched roofs.
(c) Slate Roofing
- Uses natural stone slabs.
- Durable, waterproof, and fire-resistant.
(d) Metal Sheet Roofing
- Includes GI sheets and aluminium sheets.
- Lightweight and easy to install.
- Used in factories and sheds.
(e) Asbestos Cement Sheets
- Lightweight and economical.
- Resistant to fire and weather.
(f) RCC Roof Covering
- Concrete slab used as roof.
- Very strong and durable.
- Can be finished with waterproofing layers.
5. Factors Affecting Selection of Roof and Covering
- Climate and rainfall conditions.
- Type and use of building.
- Availability of materials.
- Cost and maintenance requirements.
- Structural strength and durability.
6. Importance of Roof and Coverings
- Protects building from weather effects.
- Ensures safety and comfort of occupants.
- Improves durability of the structure.
- Enhances architectural appearance.
Role of Draughtsman Civil
A Draughtsman Civil prepares detailed drawings of roof plans, sections, slopes, and covering materials. Proper representation ensures accurate construction and effective performance of the roof system.
Conclusion
Roofs and roof coverings are essential elements of any building. Different types of roofs and materials are selected based on climate, cost, and structural requirements. Understanding these concepts helps ITI Draughtsman Civil students design safe, durable, and efficient buildings.