Siting, Design and Selection of Materials for Residential Buildings in Hilly Areas - Guidelines
2000 Edition

For load-bearing walls in mountainous residential construction, clay-based earth materials such as mud lumps, rammed earth within wooden molds, and adobe blocks measuring approximately 300 to 350 mm thick and tapering upward are advised. These should be combined with fibrous additives like straw, hay, or animal and human hair to enhance cohesion. Additionally, wooden elements or split bamboo can be inserted at corners and T-junctions between layers for increased stability. Concrete blocks, hollow blocks, stone blocks, and stabilized soil blocks are recommended only for infill purposes and not for load-bearing applications. When alternative materials are used structurally, mild steel reinforcements should be incorporated horizontally every third layer and vertically adjacent to openings to strengthen the wall system. New materials can be adopted after thorough field testing and evaluation by qualified engineers to ensure disaster resistance and structural integrity.

The code emphasizes several strategies to enhance resistance against earthquakes and strong winds. For wind resistance, roofs must be firmly anchored to walls and foundations to prevent uplift, and all structural components—including walls, beams, rafters, and roof sheets—should be securely connected. Diagonal bracing is essential in roofs and walls to resist lateral forces and prevent deformation. Building plans should avoid square shapes, favoring chamfered corners to reduce wind pressure, and natural windbreaks such as trees or terrain features are encouraged. Regarding earthquake resistance, walls and trusses require bracing to withstand lateral seismic forces, and a continuous load path must be maintained through proper connections among structural elements. Measures enhancing wind resistance often concurrently improve seismic performance, ensuring a comprehensive approach to structural safety.

To minimize disaster risks, site selection should avoid hazardous terrain features like narrow ridges, steep slopes, narrow valleys, cliffs, and gullies within a 150-meter radius. Preferred sites have hard bedrock close to the surface and stable soil conditions, while sites with poor load-bearing soils or unconsolidated sands should be avoided. Areas exhibiting signs of active faulting—such as displaced rock layers, aligned ponds or swamps, and deep ground fissures—are unsuitable. Landslide-prone zones should be excluded, favoring locations where such occurrences are rare or unknown. Additionally, sites should be easily developable with gentle slopes, ideally less than 15 degrees, be close to workplaces, and have good exposure to sunlight and ventilation. Comprehensive geotechnical evaluations are essential to confirm suitability.

For regions with significant snowfall and rainfall, roofs should have steep slopes exceeding 50 degrees to facilitate snow shedding and prevent accumulation that can lead to avalanches. Pitched roofs, particularly hip roofs with four slopes, are preferred for their effective drainage. Suitable materials include slate tiles, corrugated galvanized iron sheets, and ceramic or clay tiles supported on wooden frameworks, offering durability and resistance to water ingress. Earth-supported roofs on timber frames are discouraged; however, flat roofs made from reinforced concrete or ferrocement may be used when appropriate. Gable walls should be reinforced with diagonal bracing to resist lateral loads from snow and wind. Structural design must account for snow loads as specified in the relevant load code (IS 875 Part 4) to ensure safety and longevity.

Integrating traditional construction methods with modern disaster-resilient techniques involves utilizing local materials and craftsmanship while applying engineering principles for safety and durability. This approach requires professional oversight in the planning, design, and supervision phases to ensure structural reinforcements are appropriately incorporated. New materials may be introduced after rigorous field testing and evaluation to confirm compatibility with traditional practices and regional conditions. Designs should address multiple hazards—such as earthquakes, wind, and floods—by implementing continuous load paths, secure connections, flexible yet strong materials, and reinforced foundations and walls. This strategy preserves cultural relevance and sustainability while significantly enhancing the resilience of buildings against disasters.