Saturday, 17 August 2013

How To Waterproof Your Underground(Sump) / Concrete Water Tank

Waterproofing your concrete water tanks can be done in 2 steps.
. During construction - Integral water proofing
. After Construction - Waterproof barrier cum Hygiene coatings

For Integral Waterproofing  

 Waterproof liquids / additives are available to make concrete dense and less porous, reducing water seepage. These liquids reduce the amount of water required to be added to concrete. Less water means dense concrete and lesser pores. 

Materials Required

. Cement, Jelly, Sand, Water (Concrete Mix)


. Measure water required for the concrete mix according to the waterproof liquid's  manufacturer's data sheets.
 The liquid is added to the measured water in the dosage (per bag of cement) as prescribed by the.manufacturer's data sheets.
. The above mixture is then added to the concrete mix. 
. Pour concrete and allow for curing.

Waterproof concrete is ready... or is it really?

 Waterproof barrier cum Hygiene coating

 The above does make the concrete dense but not 100% water proof. Hence, a waterproof barrier coating is recommended.

Materials Required

. Acrylic polymer bound cementitious waterproof coating material - Forms a waterproof, flexible coating.
. 2 component food-grade Epoxy coating material - Forms a hygiene coat; Prevents fungal formation and improves water-tightness.
. Brush


. Saturate the cured cement surface with water.
. Liquid component of the acrylic polymer bound cementitious waterproof coating material is measured out into a bucket.
. The powder (cementitious) component is added slowly while stirring continuously to the liquid in the required proportion (usually 1 liquid : 2 powder by weight or as prescribed in the manufacturer's datasheet). Stirring is very important to avoid formation of lumps.
. Brush apply the mixture on the substrate. 
. Allow the coating to dry. 
. Cure the coating with water.
. Once cured, saturate the coating with water.
. Stir the contents of the 2 part epoxy first in their individual containers to a uniform consistency and then mix the the 2 components in the required proportion (usually the 2 components are available in pre-measured packs or as prescribed in the manufacturer's datasheet). Addition of water as per the datasheet.
. Apply the first coat of the epoxy system with a brush.
. Allow the coating to air-cure for about 6-8hours.
. Brush apply the second coat in a direction perpendicular to the direction of application of the first coat.
. Allow the coating to air-cure and harden. 

The above process takes about 48 hours and water can be filled in the tank after about another 48 hours.