Helpful Tips for Repainting Vinyl and Aluminum Siding
Now that you've decided to repaint, what can you do to make it as painless a process as possible? After all, the solace you take in having had to paint your siding only once in 30 years will quickly be replaced with irritation when your new coat of paint starts flaking and peeling just a few months later.
The good news is that potential problems such as these can be avoided through careful prep work. Just like building a house, repainting your vinyl or aluminum siding takes careful planning and a solid foundation. In this case, that means proper cleaning, attentive surface prep, and smart choices in both paint and application.
Cleaning Exterior Siding
Just like Monet or Matisse, you'll want to start with a clean canvas. In your case, that boils down to scrub, rinse, repeat.
The first thing you should do is take a visual survey. Keep an eye out for corroded spots, deep scratches, and any location where the bare metal is already visible. In these locations, take a non-metallic scouring pad (such as sandpaper) and scrub. Don't use steel wool or any other metallic substance, as tiny fragments left behind will cause further corrosion, keep paint from properly adhering, and cause pinholes all the things you're trying to avoid.
Rent yourself a power washer with at least 3000 psi. It should be strong enough to remove the chalking (oxidation) from your aluminum siding, or the grimy buildup on your vinyl siding, but not strip the paint or dent or otherwise damage the siding.
Start at the top and work your way down. Be cautious near soffits, windows, corners, and doorways, where water could be forced behind and cause even bigger problems down the road (such as mildew or mold).
Unlike what you might do in a regular rinse situation, keep the pressure wand fairly close to the siding to remove the chalk or crusted-on dirt. In some places bare metal may be revealed as loose paint is washed away; this is okay in spots, but if it's happening often and everywhere, step back a bit (which will reduce the pressure).
If you notice any mold or mildew, you can treat the location with a 3:1 mixture of bleach and water, or a vinegar and water mix. Let the mixture stay on the trouble spots for about 20 minutes, adding more as it dries. Alternatively, you can add TSP or other cleaning solutions directly into the power washer's reservoir and blast these danger spots that way. Either way, be sure to rinse these treated areas with regular water once the treatment is complete.
Next, let the siding dry for a couple of days, preferably in dry, sunny weather. When it's dry, assess the situation. Are any chalky areas still remaining? If so, it means just one thing wash the house again. Let it dry again. Typically two rinses should do the trick, but every house is different. Repeat as long as there are areas with moderate to heavy chalking.
Once all the dirt, chalk, and mildew is gone and the house is dry, you're almost ready to repaint. Before you do, however, you'll probably need to make one more additional step, depending on your siding type.
If you have aluminum siding, you'll need to take care of any bare metal that may have been exposed during the previous process. Prime these locations with a corrosion inhibitive latex primer. In areas where there was heavy chalking, and possibly still some minor chalking, use an exterior alkyd primer.
If you have vinyl siding or vinyl-coated aluminum siding, using a surface de-glosser would be appropriate. This acts like a solvent and will remove the shine from your siding's surface. Taking the shine off will help the first coat of paint adhere better.
You can find all of these products at your local hardware or paint supply store.
The best tool for this job is a sprayer, as it will result in the most even, uniform look for your siding. This is especially true if you opt for a satin finish (although a flat finish is recommended).
For even better results, a commercial grade airless sprayer is the ideal choice, and is often available for rent at tool rental or paint supply stores. This type of airless sprayer will draw paint directly from 5-gallon paint pails, making the whole process much more efficient. It is also especially useful for high-quality latex paints, which are thicker than regular latex paint and therefore require more power.
Paints and Additives
A high-quality, 100% acrylic latex paint in light to medium colors is the best choice for your repainting job. Dark colors and non-acrylic paints will have more trouble adhering and will expand (and thus crack) more and should be avoided. A high-quality paint is going to be more expensive, but as long as all the prep work has been done well, it'll also last a lot longer (meaning you won't have to do this again for many, many years).
You may be tempted to use a satin gloss finish, because the resulting shine would make your newly painted siding look like newly installed siding. A satin gloss, however, will also reveal every minor dent or ding your siding has acquired over the years, so the illusion of new siding would be short-lived. Choose a flat finish instead.
Many contractors recommend that the first coat of latex paint should include an exterior latex paint additive such as E-B® Emulsa-Bond®. This is a special stir-in additive that won't affect the paint color, but will help the paint bond to surfaces that are hard to coat, such as porous, dusty, or chalky surfaces. E-B® Emulsa-Bond® should only be used for the first coat. If there are any areas of your siding with even a thin film of chalk left, you should definitely use the additive.
Using an additive like E-B® Emulsa-Bond® typically eliminates the need for a costly binding primer, but you should check with your paint supplier just in case. The rule of thumb is usually, 'if in doubt, use a primer.' If you do end up using a primer, just add the E-B® Emulsa-Bond® to the primer.
Other bonding agents are available for different types of paint, such as solvent- or oil-based paints. For instance, Penetrol® is used with oil- or alkyd-based paints. However, those paint types do not perform as well on siding, and if you want the best value for your investment and more importantly, if you don't want to be repeating this project soon you should choose a 100% acrylic latex paint.
All of these paint additives can be found at a painting contractor supply store.
Once your primer or first coat has been applied and has had time to dry, it's time to repeat the process with your top coat (without the bonding agent). You might need two top coats, depending on the paint you chose. Consult with the paint manufacturer to be sure. Follow their instructions. Many people assume that a second coat is recommended to boost paint sales, but in reality it will help your new paint job perform better and last longer. Extending the life of your paint means limiting the frequency of painting, so definitely listen to what your paint manufacturer has to say.
Cleaning and Prepping Make All the Difference
In the end, repainting siding is a time- and labor-intensive task that homeowners have every right to dread. If all the right steps are followed, however, the end result is that your home will look shiny and new for years and years to come.
Choosing the appropriate high-quality paint is important, of course, but preparing the surface is key to a job well done. Cleaning, sanding, treating for mildew and mold, and spot-priming are all critical steps that can't be skipped if you expect long-lasting performance. Bonding agents and de-glossers are also very helpful.
Done right, with special attention paid to cleaning and surface preparation, your new paint job can last as long sometimes even longer as your original factory finish.