Both for esthetic and property value reasons painting a brick wall is the very last thing that you ever want to consider. When you apply paint to a brick surface it is almost always impossible to remove without destroying the face of the brick that protects it from water damage. However there are times when you really have no other choice but to paint your brick wall to provide protection and extend its life.
Preparing the Wall for Paint
First clean the wall with a detergent based soap. If you find there is any mold or moss growing you should use a bleach solution to remove it.
A pressure washer can be used but should not be set at such a high setting as it may cause damage.
Inspect the brick and mortar joints for any broken or missing material. If you find the mortar between your brick has deteriorated then you will need to point your brick before you paint it. Do not expect the paint to hold your wall together.
After the brick has been repaired and allowed to dry you will need to seal it with a commercial grade paintable water sealer. You want to use a paint based not wax or oil based sealer. There are many basement concrete paints that will provide good results.
Masonry Sealers will penetrate the brick while a latex paint will sit on the top. If you have a problem with flaking of old paint this is probably the reason.
Some masonry paints can be color matched. You may find a commercial garage floor paint that is available for tinting or in standard factory colors.
If you would like to change the color by applying a top coat then a latex paint with a primer is probably your best bet.
If you need to protect a wall that may be prone to graffiti there are anti graffiti paints formulated to allow quick cleaning without the need to repaint.
Care for your painted wall.
Now that you have painted your exterior wall you should expect to repaint it every 3 to 5 years or as needed. Painted surfaced do need more care then brick or even siding products.
Keep a watch for cracks that can allow water to penetrate the brick or gutter problems that can cause water to flow behind the brick. Water is a main reason that painted masonry surfaces chip and flake.