Anyone with older aluminum siding will be well aware of the paint chalking problem. Just rub your hand along the old siding and the chalky older paint will likely be all over your palm. Attempting to get paint to stick to this tends to be a real problem. This is often due to oxidation of the paint. Siding manufacturers originally referred to this problem as being a "benefit". They called it, "self cleaning", on the grounds that the paint literally washes from the house.
Older vinyl siding can also be a problem. UV light fades vinyl siding over time and the siding becomes very unsightly. Many unlucky homeowners and contractors have experienced this disappointment when they repainted their homes, only to discover the new paint falling off one or two months later. Both problems with older aluminum and vinyl siding is usually overcome with proper cleaning, surface preparation and re-painting.
Cleaning
You will have to rent a strong pressure washer with at least 3000 psi. You will need a pressure washer powerful enough to get rid of most of the old chalky paint from the aluminum siding and, to get rid of any dirt buildup. Start at the top course of siding and work your way downward. You will need to hold the pressure wand fairly near the siding surface to effectively remove the old paint. In some areas, you might find that the paint comes off to the bare metal. Be careful near windows, corners, soffits and doorways. The water under pressure, might be forced behind these areas creating a lot of damage. You can add TSP or other cleansing solutions into your reservoir for mildew, algae or other grime built up. You must allow your home to dry for several days in dry, sunny weather before proceeding with 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 stick better.
Application
I like to use a commercial type airless sprayer. It will draw the paint directly from your 5 gallon paint pails, through the hose and into your spray gun. These are available to hire at many tool rental locations and even some paint supply stores that supply contractors.
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 to use latex paint additive called emulsa-bond for the very first coat. Emulsa-bond is a bonding agent that you add to the first coat of paint or primer to assist it to bond to the old siding. Buy the very best grade exterior latex paint that you can afford, instead of oil or other solvent based paint. Latex paint would seem to keep up with the expansion and contraction on the siding extremely well. The high quality latex paint I buy needs no primer. I add the bonding agent directly into the very first color coat. Check with your paint supplier whether or not to use a primer. The rule of thumb is, when unsure, use a primer. If you use a primer, add the bonding agent into it before using. There are also bonding agents available for oil or other solvent based paints. One type is named penetrol. These are usually available at a painting contractor supply store. Where bare metal is exposed. I don't like spot priming as it can lead to an uneven looking top coat. When I put a primer coat on, I prime the entire area. This provides a consistent surface finish later on.
Finish Coat
Your top coat should be colour only. You should check with the paint manufacturer to determine if you need one or two top coats after the bottom coat. Like I discussed above, buy the best quality exterior paint that you can afford.
Author Resource:
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