Tips for avoiding water damage with basement waterproofing paint


Although the choices of materials for waterproofing one’s basement are numerous, it doesn’t take a scientist to tell you that waterproofing paint is one of the easiest to handle, and when used carefully, cheapest of materials available. However, waterproofing paints come in many forms, ranging from oil or latex based paints to elastomers. Their viscosity, primer requirements, thinning needs and wall preparation procedures are vastly different and it is fallacious to believe that just by knowing the basic painting procedure one can achieve the perfect sealing, even when the overall water-retention capacity of the basement is kept to a minimum by a sump pump that has been installed properly. On the other hand, the products can be handled and used without much hassle if the tips for avoiding water damage with basement waterproofing paint can be followed.

basement waterproofing paint

Tips for Oil and Latex based paints

Dry out the surface thoroughly

Though this is one of the basic truths known to any painter, many people assume that since the paint is waterproofing by nature, it will be able to settle down on wet walls or those with mold/fungi on them. The truth is that waterproofing paint is capable of repelling water only when it is dry, and to dry out, it needs a dry surface with which to chemically bond.

If the surface is wet, a film of water exists between the surface and the paint and this causes the paint to remain wet because it cannot bond with the surface. As water builds up under the paint over time, the paint and primer are turned to a mushy mixture that is of no use whatsoever.

To dry out the surface and prepare it for the paint:

  • Take a loose wire brush and brush away loose paint, mortar and flakes of old mold and while doing so, ensure that the surface is as flat as possible.
  • Use a dehydrating agent to remove the water from the wall. Note that this part of the tips for avoiding water damage with basement waterproofing paint would be useful only for a couple of hours after the drying has been carried out as water is constantly moving through concrete.
  • Use dehumidifiers to dry out the air present in the basement and one of the best sump pumps to ensure that the substratum of the basement is dry (so water cannot rise up from the floor) .
  • Apply the primer and paint.

Cover any cracks

Cracks less than 1/8th of an inch in thickness can be covered using polyurethane filler foam. As with applying paint, ensure that the surface around the crack is dry. If needed, wear a gas mask to avoid contact with any fumes that may be associated with the foam. Once the foam has settled well, apply another layer if the contours of the crack are still visible. Once you’re satisfied, wait for about an hour before beginning to paint.

Oil is better than Latex

As mentioned in the introduction, there are two major types of waterproofing paint – oil and latex. While latex gives a smooth finish, it has a tendency to become stretched when heavy objects are hung on the walls. Further, it is not very easy to clean and if you use the basement to for working with table saws or plasma cutters, it can become grimy quite easily. Oil takes on grime too but it is easier to clean and when heavy objects are suspended, there is no flaking or stretching of the paint. Further, oil based paints are cheaper and the thinners/primers required are more akin to those used for ordinary wall paint.

Tips for Elastomeric Paints

Viscosity and Thinning

Elastomeric paints work somewhat better than oil or latex based paints and can be thinned with water, but are also somewhat costlier. If you choose elastomeric paints, you should keep in mind that the viscosity of elastomeric paints is far higher than ordinary paints. Further, they are meant to be applied in this viscous form rather than thinned to a fluid form.

In addition, one should note that oftentimes the change in viscosity is not readily apparent (or no change takes place) when thinner is added, but the requisite changes are taking place in the internal composition of the mixture. Hence, if no change is apparent, one should not keep on adding water.

Dry Form Thickness (DFT)

Dry form thickness is the thickness of the coat of paint on a dry surface when the coat itself has become completely dry. This thickness in case of elastomeric paints is in the order of 10-20 mils per coat, with most walls generally requiring two coats. Compare this with the 3-5 mils of a coat of oil based paint and it becomes obvious that elastomeric paints are far thicker. Indeed, they should form a rubbery layer through which the minute details of the wall beneath should not be visible. If the forms are still visible, it is likely that the coat is not thick enough and another coating can be undertaken.

Don’t Avoid Backbrushing and Edges

One of the tips for avoiding water damage with basement waterproofing paint that is often overlooked is the need for backbrushing of viscous paint to ensure uniform application. Without backbrushing, lumps of solids can remain and this creates an uneven surface that may protect against water invasion but will collect dirt more easily and cause maintenance headaches later on.

When painting, furthermore, one of the common suggestions of our tips and blog articles for sump pumps’ sump pits becomes valid – ensure that the edges are not ignored. Ignoring them will provide water narrow spaces through which to pour in and render the waterproofing largely inept.


While providing the above tips for avoiding water damage with basement waterproofing paint, we’ve purposefully avoided creating an article that would be similar to the buying guides for sump pumps. The reason for this is that unlike sump pumps, the best paint has to be chosen by the person on the spot, as these vary in price from region to region and are often shipped from the nearest factories. That said, the rules for applying such paints are more or less uniform, and if the ones we’ve listed above are followed, it is likely that one’s basement would be free from mold, dampness and of course, water leakage for posterity, provided of course that reinforcing coats are applied at regular intervals.



Bill is a DIY plumber, handyman, and homeowner with more than a decade of experience. He has replaced and repaired sump pumps, backup pumps, float switches, check valves, and many other things around his family home. An engineer and tinkerer at heart, he is always looking to see how things work and taking on new home projects that help him grow his skillsets. He is a husband and father of two boys, has a bachelors degree in Computer Engineer and minor in Mathematics and likes to make homebrew beer in his free time.

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