Which paint is good long term to avoid wall leakage?

Water leaking should be avoided by taking care during the slab casting and wall constrcution. Preventing it by a paint is not correct. A paint may stop seeping out and you may not see it inside your house. Seeping in can't be stopped. To avoid water leakage from the walls can bearrested by applying a water proof painting on the top of the slab and repeating it as and when requried. It will cost money. Prevention is better than cure. See that cement, sand.rubble are mixed in correct proportion and laying it uniformely by making a uniform distributionwhile slab casting. Without leaving it to others personal supervison and taking the help of a knowledable man for that particular day to oversee the operation is the best way to have correct slab casted and that will ensure no leakage of water.
There are paints which are waterproof. Generally ceramic materials and latex will be present in the formulation of the paint which will make the paint water proof. These materails will stop the othermaterials in the paint to absorb water. These paints can be easily washed with soaps so that the durability will be improved. There are many paints which are manufactured by the well known paint manufcaturers and they will be used. Asiant Paints and Neorlac are the best manufacturers of these paints and you can visit any of their show rooms and select the colour you want.
If already the slab is casted and there is water lekage problems, there are some paints which can be applied on the slab top and you can get that paints in almost all the paint manufacturers of repute.

Exterior painting can at the maximum be just a temporary solution of mild seepage in rainy season. It will not solve the real problem of leaking .
Leaking occurs in old buildings.That can be expected and then extensive re plastering is one solution.
In new buildings leaking occurs due to in sufficient curing, using low grade materials,and using wrong proportion of mixing plastering and concreting materials. Here the solution for leakage on side walls i can be installing canopies,overhead covering sheets,covering he exposed walls by water proof sheets.

If affordable, tiling the exterior walls can be done. That will not only solve the leaking but will also save recurring cost of painting and give a neat and beautiful look also.

But for very minor seepage or wetness without leaking,and if the wall area is less, then we can use waterproof emulsions specially made for exterior walls. But proper put work also to be don in the suspected areas before painting.

Now a days some good quality paints are available which are successful in avoiding leakage in the walls. Some of these formulations are -

1. Acrylic Polymer Modified Paints - These are white cement based waterproof coating paints modified by addition of certain acrylic polymers. They have good bonding property and provide water insoluble micro crystalline structures which block the leakage effectively.

2. Hi-Performance Polymer Modified Paints - These paints contain flexible re-dispersible polymers. They form strong waterproof coating over the surface to be protected.

3. Protective Elastomeric Layer Paints - These are excellent in waterproofing solutions and are used for external as well as internal use as well as specialised uses in swimming pools etc. They form an excellent protective elastomeric layer over the surface and thus prevents water infiltration through it.

4. Two Component Polymer Modified Paint - It is a special paint preparation by adding liquid polymer to a cement based mixture incorporating graded aggregates and additives. This can be applied over the concrete slabs and on curing it gives excellent protection from water leakage. It is good for roofs and side walls to avoid water seepage.

Applying paints on the affected part of the wall would be a temporary solution and due to the binding property of the paint due t presence of emulsion and resins, it would work in plugging the holes though it may not appear visible with the eyes. However there are other means to arrest the leakage a few such tips are noted below -
1) An iron brush is to be used to remove the dirt and loose materials lying around the cracks. In case, the plaster has been removed, plaster the patches using mortar with the cement. Fill up the cracks with the Asian - paint Smart care Crack Seal by following the instructions appearing on the container.
2) Polyurethane Foam can seal the concrete leakage and may be conveniently employed in the larger areas. Initially, it appears as a liquid form but on contact with the surface the surface will be harder due to its close cell membrane.
3) Very small cracks can be sealed by sealed by Sealant
4) Glues - Epoxies Glues are the plastic resins and has the capability of sealing the pores effectively if the same is uniformly applied on the affected part.
Of course, Asian Paints and Neorlac have devised paints which can readily seal the pores due to presence of rubber and resins added in their composition..