Constructing a water tank involves a series of steps to ensure it is durable, waterproof, and suitable for long-term use. Below are the typical steps involved in constructing a water tank, focusing primarily on reinforced cement concrete (RCC) tanks as an example:
1. Planning and Design
- Site Selection: Choose a site that is stable, accessible, and appropriate for the tank’s size and purpose.
- Design Considerations: Consider the type of tank (underground, overhead, or ground-level), storage capacity, water pressure, and safety requirements.
- Blueprint and Approval: Create a detailed design plan, including the tank’s dimensions, reinforcements, inlet/outlet positions, and safety features. Obtain necessary approvals from local authorities if required.
2. Excavation (for Underground Tanks)
- Marking: Mark the area according to the tank’s dimensions.
- Excavating: Excavate the ground to the required depth. Ensure the sides and bottom of the excavation are stable and level.
3. Foundation Preparation
- Base Compaction: Compact the soil at the base of the excavation to prevent settlement or uneven subsidence.
- Gravel Layer (Optional): Lay a layer of gravel or sand at the base to enhance drainage and prevent water seepage from below.
- Waterproofing Layer: Add a waterproofing layer (such as a plastic sheet or bituminous membrane) to prevent seepage.
4. Formwork Installation
- Install Formwork: Set up wooden or metal formwork to shape the concrete base and walls of the tank. Ensure the formwork is secure and can hold the wet concrete in place during pouring.
5. Steel Reinforcement
- Base Reinforcement: Place steel reinforcement bars (rebar) on the tank base according to the design specifications. The rebar helps in reinforcing the tank to withstand water pressure.
- Wall Reinforcement: Position the rebar along the walls of the tank to provide additional strength. Ensure proper spacing and placement as per the structural design.
6. Concrete Pouring
- Base Concrete Pouring: Pour the concrete for the base of the tank. Use a vibrator to remove air pockets and ensure uniform compaction.
- Wall Concrete Pouring: After the base is set, pour concrete for the walls. Use vertical sections to avoid cold joints. Continue vibrating to ensure there are no gaps or weak spots.
- Curing: Allow the concrete to cure properly, usually by keeping it moist for at least 7 days. This ensures maximum strength and prevents cracks.
7. Waterproofing the Interior
- Waterproof Coating: Apply a waterproofing coating (such as epoxy or cement-based waterproofing compounds) to the inside walls and floor to prevent water leakage.
- Seal Joints: Ensure that all joints, particularly where the walls meet the floor, are sealed with appropriate waterproofing materials or expansion joint sealants.
8. Formwork Removal
- Remove Formwork: After the concrete has set and cured properly, carefully remove the formwork without damaging the tank structure.
- Surface Smoothing: Smooth the tank’s inner surface, removing any sharp edges or projections that could damage the waterproofing layer or the tank itself.
9. Plumbing and Fittings
- Inlet/Outlet Installation: Install the inlet and outlet pipes, along with overflow and drainage pipes. Ensure proper sealing around pipe penetrations to prevent leaks.
- Valves and Vents: Install valves for water control and vents to release any trapped air.
10. Lid or Roof Construction (for Overhead Tanks)
- Roof Formwork and Reinforcement: For overhead tanks, create a roof or lid using formwork and reinforcing steel.
- Concrete Pouring for Roof: Pour concrete to form the roof, ensuring proper curing.
- Roof Waterproofing: Apply waterproofing material to prevent leaks from the top.
11. Exterior Finishing
- Plastering: Apply a cement plaster finish to the exterior of the tank for additional protection and to give a smooth finish.
- Painting: Paint the exterior with weatherproof paint to protect the concrete from environmental factors (for overhead or exposed tanks).
- Waterproofing: Consider applying an exterior waterproof coating, especially for underground tanks.
12. Final Inspection and Testing
- Water Filling Test: Fill the tank with water and monitor for any leaks. Leave the tank filled for at least 24-48 hours to observe any seepage or structural weaknesses.
- Rectify Issues: If any leaks or cracks are found, repair them using appropriate waterproofing methods or structural fixes.
13. Tank Cleaning and Commissioning
- Clean the Tank: Before use, clean the inside of the tank to remove any debris, dust, or contaminants.
- Commissioning: Once the tank is ready and tested, it can be connected to the water supply system and used.
Following these steps ensures that the water tank is constructed safely, securely, and in a way that will serve its purpose for years with minimal maintenance.
