Factors for selecting construction materials

The selection of a construction material is a decision that balances performance, cost and availability so that the structure is safe, durable and economical.

1. Strength and stability: the material must carry the expected loads (compression, tension, bending, shear) with a proper factor of safety.
2. Durability: it should resist weathering, moisture, chemical attack, insects and fire for the design life.
3. Cost and economy: both initial cost (purchase, transport, labour) and life-cycle cost (maintenance, repair) should be low.
4. Availability: locally available materials reduce transport cost and construction time. In Nepal, for example, locally available river sand, bricks and stone are usually preferred.
5. Workability: the material should be easy to cut, shape, place and finish with the available tools and skills.
6. Appearance and finish: important for exposed surfaces such as facing stone, tiles and paint.
7. Thermal and acoustic properties: insulation, thermal conductivity, sound absorption and fire resistance affect comfort and safety.
8. Weight: lighter materials reduce dead load and foundation cost.
9. Maintenance: materials needing little upkeep are preferred.
10. Environment and standards: the material should comply with the relevant standards (Nepal Standards, IS, ASTM), be eco-friendly, and suit the local seismic and climatic conditions as per NBC.