By its very nature, a basement is below ground level and so is automatically susceptible to the problems of damp, subsequently using any old emulsion as a basement foundation paint will simply not be suitable. Instead you need to choose a basement foundation paint that is either marketed as a water sealant/barrier or at least as a water-resistant paint.
Bearing in mind that you’re after basement foundation paint, the color of it doesn’t have to be the final color you want for the finished basement walls. If you’re using a water-proof paint as the foundation then chances are it will be a colorless sealant, over which you can then paint a colored foundation as a primer for the top coats. If it is colored, so long as the basement foundation paint isn’t a severely dark color – you will be able to paint over it.
White is always a good color to use as a foundation in a basement. Not having any natural light, or at best restricted natural light, you’ll want to make the basement wall colors as bright as possible and white basement walls are ideal – but they do really require a while basement foundation paint. Otherwise grey basement foundation paints are OK, as they can be over-painted with light colors and dark ones.
Before Painting the Walls
Just because it’s the basement and not many people will see it is no excuse for not making a good job of painting the basement walls. And that good job begins with painting a great foundation for the basement paint. So, exactly the same as painting walls in the main living space you need to prepare the walls.
The first thing to do is to make sure there’s no obvious ingress of water into the basement and especially trickling down the walls of the basement. If there are, you must find where the water is coming from and stop it.
The next job is to patch up any missing mortar or holes in the wall surface. You’re not necessarily after a perfectly flat sheet-rock finish here, but a smooth looking wall will make the overall appearance of the job look a lot better.
Finally, with the walls dry, remove any old wall paper coverings, old flaking paint and dust – and you are then ready to start painting the walls.
After all that preparation, especially removing any obvious sources of water and moisture, you might well wonder why you should go to the expense of buying a special sealant or water-resistant basement foundation paint. Well, the fact is that no matter how water proof you try to make your basement it will attract moisture. If you’ve got a dirt or gravel basement floor – moisture will almost certainly rise up through it.
Even if you’ve got a sealed concrete floor and have scrupulously checked for any water ingress to the basement, go down into the basement when the heating is on and you’ll almost certainly feel moisture on the surfaces of the basement walls.
The reason for this is that heat from the heating pipes, let alone a boiler, in the basement creates moisture when in contact with cooler air down there. Subsequently a non-water resistant paint on the walls would soon start to deteriorate.