A house builder should be very careful when choosing the material. It must be kept in mind that the costliest material may not always be the best. Here’s a look at some essential properties of materials required during the construction of a house:
Cement: Many types of cement is produced these days but for house builders, only PPC cement is available. Always go for a reputed brand of cement and see that the bags are IS 1489 (Part I) marked. Choose a cement lot as fresh as possible. Cement bags carry the week and year of manufacturing on them. See that cement lots supplied are fully dry, each bag weighs 50 kg and is not more than a month old.
Steel: Choose deformed steel bars instead of plain bars. See that these are IS 1786 marked. It’s also called Tor steel. Choose Tata or SAIL steel. Choose a fresh lot. Ensure it is free from rust and in straight length, instead of coils. Look for D factor i.e. prefer Fe 500D grade over Fe 500 steel. Ask supplier for copy of test certificate of steel to check its correct weight, diameter and date of manufacture.
Bricks: Always choose good quality bricks, red in colour, 9”x4 3/8”x 2 11/16” in size, having sharp corners and free from distortions. Immerse few bricks in water and see that after 24 hours, these don’t gain more than 20 per cent of weight. A brick broken into two halves shouldn’t show lumps of lime on broken faces. Strike two bricks together and see that these produce sharp, ringing sound.
Sand: Choose only coarse sand for construction. Never use fine sand. Coarse sand when gripped in fist will feel like cutting into skin while fine sand will just slip away. See that the sand doesn’t contain more than 3 per cent clay or silt in it. This can be checked by adding sand in a glass of water and by measuring the thickness of clay layer settled at the bottom.
Crushed stone: Coarse aggregate used in construction should be free from flaky material. Commonly, it’s called crusher. See that it’s free from dust, clay or earth. Use 20 mm down aggregate for RCC work. Requisition it directly from a good source like Pathankot through local dealers or unions.
Electric wires: Choose wires in copper, not aluminium and with multiple strands. Choose IS 694 (Part I) marked wires not IS 694 (Part II) marked ones. Choose 99.97 per cent electrolytic grade. Check wire insulation as three layered that is water-resistant, heat-resistant and fire-retardant with HRFR mark. Choose the right size of wires.
Switches and plates: Go for modular switches only. Choose fine quality polycarbonates of FR grade. Prefer white colour as these don’t go out of fashion. Check their operation as noise proof, having ergonomic design and have spark shields.
Conduits & bends: Choose PVC conduits instead of MS conduits. Look for heavy duty conduits with 2 mm thickness. Heavy duty conduits carry green markings while light duty conduits carry red markings.
Water supply: Choose IS1239 marked, medium duty GI pipes having blue bands at ends. Reject pipes with yellow bands. If choosing PVC pipes, look for IS4985 marked pipes as these are suitable for drinking purpose. In PVC pipes, choose a reputed brand and minimum 2.7 mm thickness.
Sanitary pipes: Choose un-plasticised PVC SWR pipes, instead of CI pipes. Look for IS13592 mark on pipes. The pipe fittings should carry IS 14735 mark on them.
— The writer is former HoD and engineer-in-chief, Civil Engineering
Department in a Punjab PSU