The number one problem when painting aluminum siding is the chalking of the old paint. If you rub your fingers across the siding you will notice a white chalk on your fingers.The chalking is caused by the oxidation of the paint and will create a major problem if this is not corrected before you began to apply paint to the surface. However, there are a few steps you can take to prevent the paint from peeling with sufficient cleaning of the surface and preparing the surface to paint correctly.
The first step is to pressure wash the surface using a pressure washer. You will need a pressure washer which is powerful enough to remove the chalky paint from the siding. But, before you began to pressure wash you will need to clean the surface using a mild detergent such as T.S.P, which is readily available at most paint or hardware stores. Most pressure washers have a chemical injection hose which will allow you to inject the detergent through the pressure washer which will save you a lot of time and hard work.
After applying the detergent you will then need to pressure wash. Began at the top of the siding and work your way down, keeping the wand of the pressure washer close to the surface of the siding and using a wide pressure tip. If you pressure washing correctly you will notice the white chalk began to come off of the siding as you apply the water to the surface. Before going to the next step you will need to allow you house to fully dry which is usually about twenty four hours.
Applying a primer to the surface before you paint is a critical step in the process of painting aluminum siding. The primer will allow the paint to bond correctly to the surface. A good latex primer applied using an airless sprayer is an excellent choice.
I also recommend using a paint additive called Emulsa-Bond which you can add directly to your paint or primer which will aid in proper bonding of the paint to the surface. This product is inexpensive and can also be purchased at most paint or hardware stores.
When choosing a paint it is important that you purchase a high quality latex paint. Latex paint will bond better and will retain its color better than an oil based paint will. Apply the latex paint using a airless sprayer, just as you did when you applied the primer.
You should check with your paint manufacturer to see if you require one or two finish coats of paint after applying your primer. If you are using a quality latex paint, one coat should be sufficient.
If you have properly cleaned the surface as described in this article and you have primed and painted the surface correctly, you will have a beautiful, long lasting paint job which you will enjoy for many years to come.