Anyone with older aluminum siding is well aware of the paint
chalking problem. Just rub your hand along the old siding and
the chalky old paint will be all over your palm. Trying to get
paint to stick to this could be a real problem. This is due to
oxidation of the paint. Siding manufacturers originally referred
to this problem as a “benefit”. They called it, “self cleaning”,
as the paint literally washed off the house.
Older vinyl siding is also a problem. UV light fades vinyl
siding over time and the siding becomes very unsightly.
Many unfortunate homeowners and contractors have experienced the
dismay, when they repainted their homes, only to find the new
paint peeling off a few months later. Both problems with older
aluminum and vinyl siding can be overcome with proper cleaning,
surface preparation and re-painting.
Cleaning
You will need to rent a powerful pressure washer with at least
3000 psi. You will want a pressure washer powerful enough to
remove most of the old chalky paint off the aluminum siding or,
to remove any dirt buildup on the old vinyl siding.
Start at the top course of siding and work your way down. You
will need to keep the pressure wand fairly close to the siding
surface to effectively remove the old paint. In some areas, you
may find that the paint comes off to the bare metal. Be careful
near windows, corners, soffits and doorways. The water under
pressure, can be forced behind these areas causing damage. You
can add TSP or other cleaning solutions to the reservoir for
mildew, algae or other grime built up. If you do use a cleaning
solution, be sure to completely rinse it off with your pressure
washer. You should allow your home to dry for several days in
dry, sunny weather before proceeding to the painting process.
If you are repainting vinyl siding or vinyl coated aluminum
siding, you may need a surface de-glosser. This is a solvent
type product used to remove any shine on the surface and to help
your first coat to adhere better. You will have no trouble
finding a good de-glosser at your local paint supply store.
Application
I like a commercial type airless sprayer. It will draw the
paint directly out of your 5 gallon paint pails, through the
hose and into your spray gun. These are available to rent at
many tool rental locations and even some paint supply stores
that supply contractors. If your paint is real high quality
latex, it will be thicker than regular latex paint and will
require a more powerful airless sprayer.
Priming
This step is equally as critical as the step above. Actually,
the cleaning and surface preparation phases will make or break
the results of your project.
I like a latex paint additive called emulsa-bond for the first
coat. Emulsa-bond is a bonding agent you will add to the first
coat of paint or primer, to help it to bond to the old siding.
I buy the best grade exterior latex paint, rather than oil or
other solvent based paint. Latex paint seems to keep up with the
expansion and contraction of the siding very well. The high
quality latex paint I buy needs no primer. I add the bonding
agent directly into the first color coat. Check with your paint
supplier whether or not to use a primer. The rule of thumb is,
when in doubt, use a primer. If you use a primer, add the
bonding agent into it before applying. There are also bonding
agents available for oil or other solvent based paints. One type
is called penetrol. These are usually available at a painting
contractor supply store.
Many contractors will spot prime areas, especially where bare
metal is exposed. I don’t like spot priming because it can lead
to an uneven looking top coat. When I put a primer coat on, I
prime the entire home. This gives a uniform surface finish later
on.
Finish Coat
Your top coat will be color only. You should check with your
paint manufacturer to see if you need one or two top coats after
the base coat. Like I mentioned above, buy the highest quality
exterior paint.
In Conclusion
Proper cleaning and surface preparation are the two main
ingredients to a successful painting job. A bonding agent in the
first coat is also very critical to avoid paint peeling off
later on. Using these techniques, I’ve re-painted homes that
have lasted far longer than the original factory applied finish.
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