Bricks are a very sturdy and durable building material that has been, and continues to be, in use all over the world. In addition to this, they also have a certain aesthetic appeal not found in other building materials. Just look at all those magnificent buildings made with bricks dating to earlier centuries. These can be found in Europe, the Americas, Middle East, and Asia.
Like any other building material, however, bricks can get old after years of exposure to the sun, rain, and snow. Dirt, soot, efflorescence, and mildew can accumulate on their surfaces and make them look seedy and unappealing. Fortunately, the right kind of paint, primer, brushes, and cleaning materials can transform your old brick wall into an attractive and pleasing sight.
The best type of paint for your outdoor brick walls is a 100% acrylic elastomeric paint. Acrylic paints are durable, resistant to dirt, and easy to clean. With the addition of elastomer binders, these properties are further enhanced. Perhaps more important, they provide the paint coating with elasticity and flexibility.
You can begin the application of elastomeric paint with a thorough cleaning of the brick surface. Use a wire brush to remove dirt, dust, or any efflorescence from the wall. To prevent any future florescence, find its source and fix it. Remove any peeling paint and loose mortar, and fix any loose bricks. If you find cracks, scrape and widen them to reveal fresher surface and seal them with 100% acrylic or silicon caulk. Mildew can be removed with a homemade solution of three parts water and one part household bleach.
For you final preparation, use a power washer to spray to entire wall to rid it of all forms of debris. You can use plain water if the dirt is not too stubborn, otherwise you can mix detergent into the water but be sure to rinse it thoroughly afterwards.
You need not prime the wall if the existing coat is a latex paint and is still in good condition otherwise you should use a primer that is compatible with your chosen paint. If you are not sure if the existing paint is latex, it is advisable to prime.
Allow the primer to dry completely, then begin to apply the elastomeric paint using rollers and brushes as necessary. If you are painting over a latex paint that is still in fine condition, one coating should suffice. If not, apply two coatings, but wait until the first is dry before applying the next.