5.1 Handling of identified construction materials

Handling of construction materials is the safe and careful receiving, inspection, loading, offloading, moving, stacking, storing and issuing of materials once they have been identified on site, so that they reach the point of use in good condition and without injury to workers. Poor handling is one of the main causes of waste on Kenyan sites: cement sets in the bag, steel rusts, glass breaks, timber warps and blocks chip, all of which increase cost and delay the work. In practice, each material is checked against the order on delivery, offloaded with suitable equipment, stored according to its properties, protected from weather and theft, and issued in the right order and quantity. Example: on a classroom block for a secondary school in Kitui, the storekeeper received cement into a raised, roofed store, stacked blocks on level ground near the walls being built, and kept reinforcement off the ground on timber bearers, so that wastage stayed below 3% for the whole project.

Tools and Equipment for Handling Materials

Principles of Handling Construction Materials

• Handle as little as possible: Every extra movement increases damage and labour cost, so materials are delivered and stored as close as practical to where they will be used.
• Use the right equipment: Heavy, bulky or fragile items are moved with trolleys, pallet trucks, hoists or suction lifters rather than by hand.
• Protect from weather: Materials affected by moisture or sun, such as cement, timber, plaster boards and paints, are kept dry and shaded.
• Store on firm, level, clean ground: Stacks on uneven or wet ground lean, collapse or become contaminated.
• Keep different materials separate: Sand, ballast and hardcore are kept in separate heaps, and chemicals are kept away from food and water.
• First in, first out: Older stock, especially cement and chemicals with a shelf life, is issued before newer stock.
• Keep records: Deliveries, issues and balances are recorded so that losses, theft and over-ordering are detected early.
• Work safely: Correct lifting techniques, PPE and stable stacks protect workers from injury.

Steps to Receive and Store Materials on Site

1. Prepare the storage area: Before delivery, clear and level the area, provide bearers or pallets, and make sure covered stores are ready for weather-sensitive materials.
2. Check the delivery documents: Compare the delivery note with the purchase order for type, quantity, size and specification.
3. Inspect the materials: Check for damage, wrong grade, expiry dates, KEBS marks and signs of moisture before accepting.
4. Count or measure the quantity: Count bags, blocks, sheets and lengths, and measure volumes of sand and ballast in the lorry.
5. Offload safely: Use suitable equipment and enough workers, keeping people clear of tipping lorries and swinging loads.
6. Stack and store correctly: Place each material in its designated area, on bearers or pallets, in stable stacks of the correct height, and cover where needed.
7. Record the delivery: Sign the delivery note, note any shortages or damage, and enter the quantities in the stores register.
8. Issue materials in order: Issue materials against a signed requisition, oldest stock first, and record each issue.
9. Inspect stored materials regularly: Check stacks for damage, moisture, rust or theft, and correct problems promptly. Example: a storekeeper for a contractor building a hostel at a university in Njoro rejected 40 bags of cement with hard lumps at delivery and recorded the shortage on the delivery note, so the supplier replaced them free of charge.

Handling and Storage of Specific Materials

Calculating Storage Space for Cement

Example: a contractor building offices for a county government in Kakamega expects a delivery of 400 bags of cement, each bag occupying about 0.7 m by 0.4 m on plan, stacked 10 bags high.

Number of stacks = Number of bags ÷ Bags per stack

Number of stacks = 400 ÷ 10

Number of stacks = 40 stacks

Floor area per stack = Length × Width of one bag

Floor area per stack = 0.7 m × 0.4 m

Floor area per stack = 0.28 m²

Floor area for cement = Number of stacks × Floor area per stack

Floor area = 40 × 0.28 m²

Floor area = 11.2 m²

Extra space must be added for aisles, a gap of about 300 mm from the walls, and access for issuing the oldest stock first.

Steps to Lift a Load Manually

1. Assess the load: Check the weight, size and shape of the load and whether help or equipment is needed, avoiding loads over about 25 kg for one person where possible.
2. Plan the route: Clear obstacles from the path and decide where the load will be put down.
3. Position your feet: Stand close to the load with feet apart, one slightly forward, for a stable base.
4. Bend the knees, not the back: Squat down by bending the knees and hips, keeping the back straight.
5. Get a firm grip: Grip the load securely with the palms and fingers, wearing gloves where edges are rough or sharp.
6. Lift with the legs: Straighten the legs smoothly, keeping the load close to the body and the back straight.
7. Move without twisting: Turn by moving the feet rather than twisting the trunk, and keep the head up.
8. Put the load down carefully: Bend the knees to lower the load, then adjust its position once it is down. Example: at a hotel extension in Naivasha, the foreman trained casual workers in this lifting method and provided sack trolleys for cement, and back injury complaints dropped noticeably.

Safety Precautions in Handling Materials

• Wear PPE: Use gloves, safety boots and helmets when handling materials, and goggles and dust masks for cement, lime and chemicals.
• Keep stacks stable and low: Stack materials evenly and limit heights so that stacks do not topple onto workers.
• Use mechanical aids: Use trolleys, pallet trucks, hoists and cranes for heavy items, operated only by trained persons.
• Keep clear of lifting operations: Do not stand under suspended loads or near tipping lorries.
• Keep access routes clear: Do not store materials on walkways, in front of exits or too close to trench edges.
• Handle hazardous materials correctly: Follow label instructions, avoid skin contact with cement and chemicals, and wash after use.
• Report damage and accidents: Report damaged materials, unsafe stacks and any injuries immediately to the supervisor.

Causes of Material Wastage Through Poor Handling

• Exposure to moisture: Cement, lime and plaster set in the bag, and timber and boards swell or rot when left in the rain.
• Rough handling: Dropping or throwing blocks, tiles, glass and sanitary fittings causes chipping and breakage.
• Poor stacking: Overloaded or uneven stacks collapse, damaging materials and endangering workers.
• Contamination: Sand and ballast mixed with soil, leaves or rubbish weaken concrete and mortar.
• Theft and pilferage: Unsecured stores and poor records allow materials to disappear.
• Expiry and deterioration: Cement, paints and adhesives stored too long lose quality and must be discarded.
• Over-ordering and double handling: Ordering too much or moving materials several times increases damage and cost. Example: a SACCO building its offices in Murang'a reduced its cement wastage by about Ksh 60,000 after the contractor began ordering in smaller, scheduled deliveries and storing bags in a raised, locked store.

Chapter Summary

This chapter explored the proper handling of various construction materials, emphasizing techniques that preserve material integrity and ensure efficient use on-site. It detailed the methods for identifying safety requirements specific to different construction materials, highlighting the importance of recognizing hazards associated with their storage, transportation, and manipulation. The discussion extended to the comprehensive safety requirements necessary to protect workers and prevent accidents, including the use of personal protective equipment and adherence to safety protocols. Understanding these safety measures is critical for maintaining a secure work environment and complying with regulatory standards. The chapter also underscored the role of careful material handling in minimizing waste and project delays. Overall, it provided a foundational framework for managing construction materials safely and effectively throughout the construction process.