Constructing a Water Storage Tank on Your Terrace

When it comes to ensuring a steady water supply for your daily household needs, constructing an overhead masonry water tank on your terrace is a cost-effective option. In this guide, we’ll delve into the key specifications and steps for building such a tank, providing you with a comprehensive understanding of the process.

Choosing the Right Location

Selecting an appropriate location for your water storage tank is crucial. Consider the following factors:

Proximity to Water Connections:

• Ensure the tank is close to water connections to minimize the length of the delivery pipe.

Visibility:

• Keep the tank inconspicuous from the main road and building compound.

Overflow Considerations:

• Plan for the overflow pipe discharge point to prevent damage in case of tank malfunction.

Bottom Clearance:

• Provide a minimum 30 cm bottom clearance for easy access and maintenance.

Determining the Tank Size

The size of your tank depends on your water storage needs. Refer to Table 1 for suggested tank sizes based on water capacity. Ensure to consult a structural engineer for customized designs.

Net Capacity (Liters)	Internal Size (L x B x H) (cm)
300	70 x 70 x 75
600	90 x 90 x 90
900	105 x 105 x 90
1200	120 x 120 x 100
1400	120 x 120 x 115
1600	120 x 120 x 120
1800	130 x 130 x 125

Step-by-Step Construction Process

1. Construction of Bottom Slab

• Use reinforced cement concrete for the bottom slab with a mild slope towards the scour pipe outlet.
• The thickness of the bottom slab is 10 cm for specified sizes.
• Consult a structural engineer for other sizes or combinations of tanks.

2. Construction of Tank Walls

• Build tank walls using brick masonry in cement mortar.
• Lay the first course immediately after concreting the base slab to ensure a good bond.
• Complete the remaining masonry within a week of laying the slab.

3. Installation of Tank Fittings

• Use galvanized iron (GI) fittings, including scour pipe, delivery pipe, overflow pipe, inlet pipe, mosquito-proof coupling, and ball valve.

Detail A: Scour Pipe
Detail B: Delivery Pipe
Detail C: Inlet Pipe
Detail D: Mosquito-Proof Coupling

4. Plastering of Tank

• Plaster the base slab and sidewalls with 15 mm thick cement mortar.
• Round junctions to reduce water pressure.
• Ensure leak-proof joints for all pipes.
• Apply neat cement punning on the inner surface and top side.

5. Curing of RCC and Brickwork

• Follow general curing specifications.
• Fill the tank gradually to prevent concrete cracks due to shrinkage.

6. Construction of Top Slab

• Use precast reinforced cement concrete for the top slab.
• Ensure a smooth finish and embed the C.I. hinged cover frame during casting.

7. Testing of Tank

• Test water tightness at full supply level.
• Satisfactory results if external faces remain dry for seven days after filling.

By following these steps, you can construct a reliable overhead masonry water tank on your terrace to meet your household water storage needs.