Aluminum siding was widely introduced after World War Two and many houses are still clad with aluminum. We’ll show you how to properly prepare and paint aluminum siding so that it will look great and last for years to come.
Painting aluminum siding requires thorough cleaning with an abrasive sponge and an etching cleaner like TSP E to provide a surface that the paint will adhere to the slick aluminum. Prime paint exposed metal with a purpose aluminum siding primer and topcoat with a blend of EB Emulsa and Sherwin Williams Duration paint. Always paint in a light color to avoid warping from heat retention.
|Two step ladders and plank||Paint sprayer (optional)||Paint trim guard|
|Scaffolding||Paint roller tray||Paint stirrer|
|Drop sheets||Roller||Angle paintbrush|
|Painters tape||Roller cover with 1” – 1 ½ “ nap||Small foam roller|
|Wire brush||Spatula||Paint extension handle|
|Nylon brush||Putty knife||Paint mixing bucket|
|Dry cloths||Cleaning rags||Goggles|
|Face mask||Steel Wool||Gloves|
How To Prepare Aluminum Siding for Painting
The original Aluminum siding color was baked on during manufacture. The baked-on color oxidizes as it ages creating a chalky residue. This residue has to be removed along with dirt and cobwebs prior to painting. You have to clean deeper before painting than you might just to freshen up.
If the coating you’re painting over is not the original coating scrape any loose or peeling areas. Start with 80 grit sandpaper (no rougher or you will damage the siding) then feather the edges with 220 grit sandpaper.
Wash the siding with a pressure cleaner or by hand using an abrasive sponge pad and soapy water. Apply a mixture of TSP E* (Trisodium Phosphate E for Environmentally friendly) and water with a scrub brush, abrasive sponge pad or steel wool. TSP E will both clean the siding and prepare the surface to bond with the new paint
*TSP is safe for humans and animals but the phosphate component causes algae blooms in waterways. TSP E has zero phosphates and is environmentally safe.
Wear goggles, gloves and a mask when using TSP E. The mixture instructions are on the bottle.
Water any plants around your house before using TSP E because wet plants will soak up less spill.
Choose a pressure cleaner that allows you to mix soap or TSP E with the water. They often come with an attachment that allows you to apply a soap or TSP E mixture from a second bucket.
Apply the soap or TSP E mixture on a low pressure setting then wash off with water on a high-pressure setting. Set the pressure washer to 2500 to 3500 psi using a wide-angle tip. (Do not use a zero degree tip because you will dent the aluminum). Gas-powered washers generate more pressure than electric washers and get better results. Dial-up the pressure on the machine as required.
Aim the pressure cleaner downwards at an angle of 15% so that you don’t get water behind the siding or run the risk of blasting the siding off the house. Stand 2 feet from the wall and move in and out as required to remove ingrained dirt and stains.
Mildew has to be removed because mildew can grow underneath new paint. Use water and chlorine bleach* to clean off mildew. If you find mildew on caulking then use something like Goo Gone adhesive remover then clean off the Goo Gone with soap and water.
*Bleach is a corrosive chemical irritant that can damage surfaces like skin and fabric. Never mix bleach and ammonia for any reason, the results can be fatal. Do not mix bleach with other household cleaners that may contain ammonia or to mix bleach with vinegar. Vinegar and bleach will create a chlorine gas that is an extremely toxic health risk.
The TSP E will separate the bond between the aluminum and the oxidation and create a white milky runoff in the water. Rinse as you go: don’t leave the TSP E on too long; just a few minutes and less if it’s a hot day. Hose off all residue, soap and chemicals with a garden hose if you’re not using a water pressure cleaner.
Allow to dry thoroughly over two or three days.
Check for residual chalk by wiping your hand along the surface.
How To Repair Aluminum Siding
- Repair dents by screwing a self-tapping screw into the deepest part of the dent then pull out with pliers. Take off all the surrounding paint with sandpaper.
- Clean with a dry rag.
- Mix and apply a two-part epoxy compound or auto filler.
- Allow to thoroughly dry then sand down with 120 grit sandpaper.
How To Prime and Paint Aluminum Siding
Always refer to the Technical Data Sheet (TDS) related to each paint product, not the Material Safety Data Sheet. The TDS will tell you exactly how you should apply their paint product.
IMPORTANT: Do an adhesion test before proceeding with painting, either the scratch method or the X method. The purpose is to determine whether or not the paint you’ve chosen will adhere to your vinyl siding
- Scratch: Find a small section that won’t be seen or an offcut of siding. Paint that section, allow to cure for at least twenty-four hours then try and scratch it off with your fingernail. If the paint comes off either you haven’t washed it properly, you have the wrong paint or you will have to apply water-based primer paint.
- The X test should be done at the same time as the scratch test: Apply the paint as before then create a series of hatch marks over the paint twenty-four hours later with a standard razor. Now put blue tape over the cross-hatched area. Burnish it with your fingers to ensure good adhesion then pull it off.
If the paint passes both tests go ahead and paint.
The only time you will need a primer paint is if the original factory coating has failed completely and exposed raw aluminum. For small areas use a spray can of self-etching primer from an auto parts store and follow the directions.
Choose a self-priming acrylic paint designed for use on aluminum siding: Apply two coats.
Ideally, add E-B Emulsa Bond (1 quart or 1 liter) into a top rate self-priming topcoat like Sherwin Williams Duration Self Priming Acrylic Paint (1 gallon or 4 liters): E-B Emulsa Bond improves adhesion and increases the coverage of most coatings. This combination of paint will also prevent oxidant from leaking onto the foundation or lower storey brickwork.
Sherwin Williams Duration Self Priming Acrylic Paint has zero VOCs (Volatile Organic Compounds).
Alternative paints include:
- Pittsburgh Manor Hall (Pittsburgh Paints)
- Super Paint (Sherwin Williams) with E-B Emulsa Bond
Avoid using a latex primer that contains ammonia because gas bubbles may form and lift the paint.
Aluminum siding expands and contracts with heat and cold. Unpainted siding might be exposed between the joints as the siding fully contracts.
Paint shaded portions of the house. Direct sunlight can cause cracks and bubbles in the paint if it dries too fast. The paint will become thick and hard quickly in direct sunlight on a warm day.
A satin finish will look like the original factory coating and is easier to clean. Flat finish paint is best if you want to hide dents.
Mask doors, windows and anything else in proximity that you don’t want to be painted: Paint from a spray gun drifts further than paint from a roller or brush so cover everything. Make sure there are no cars around.
Minimize overspray by using a smaller spray tip and a lower pressure setting.
Use a handheld masking machine like the 3M handheld masker to quickly and easily protect trim, windows and doors.
Flower beds and grass also need to be protected from overspray.
Choose the right day to paint, not colder than 50 F (10 C) and not raining at all. Rain, moisture and dew will ruin the finish.
Beware of bugs settling on the wet paint and condensation forming in the evenings. Finish painting about two-hours before sundown to allow for drying before evening.
Use two (2) step ladders and a plank so that you can move back and forth and spray evenly; ideally, use scaffolding which is safer and easier.
Stir the E-B Emulsa Bond and Sherwin Williams Duration paint thoroughly with a paint stick.
- Poor the mixed paint into a paint pot that you can hold in your hand if you’re going to use a paintbrush.
- Dip the brush halfway into the paint and tap once on the side of the pot. This will load the brush properly without causing drips. Don’t wipe the brush on the edge of the pot. This just creates a mess.
- Apply the paint using the tip of the brush using just enough pressure to arch the tip[ of the brush. This will allow the paint sored in the bristles to make its way to the surface then onto the wall.
- Use a variety of paint shields for edge and corner work to prevent overspray.
- Spray paint in long even strokes flexing your wrist at the end of each stroke back and forth to keep the nozzle an even distance away from the wall.
- Spray from top to bottom so that drips don’t ruin your work.
The best way to paint aluminum siding is with an airless spray painter*. Rolling and brushing takes too long and the finish on smooth siding won’t be as nice. You will require a fine finish tip.
*The best airless paint spray gun, certainly for DIY, is probably the Graco Magnum 262800 X5 according to the review sites and is expensive at around $350.
- Fully adjustable paint flow
- Paint can be applied without being thinned
- Paint can be sprayed directly from a bucket
- Can be used constantly, up to 125 gallons a year: an opportunity to become popular with your DIY friends.
- Fast and easy clean up connecting to a garden hose
- Switch tip – reverse the tip to clear clogging.
- Can be used indoors and outdoors
The best spray paint tip is the FF LP tip (Graco RAC X Tip with SmartTip Technology)
- Sprays at up to 50% less pressure
- Reduces overspray and waste
- Provides a reliably consistent spray pattern
- Easiest pattern overlap
- Reduces preparation and clean up
- Up to twice the life of regular tips
- Can be used with any paint spray gun
Wear goggles, gloves, mask and plastic coverall.
Choose a lambswool roller with a ½” nap* and a synthetic fiber paintbrush for a smooth finish. Keep your paintbrushes fresh by washing them in water regularly. You will need a roller and a brush to access areas that you can’t finish properly with a sprayer: corners and areas behind downpipes for instance.
*nap: The thickness of the cover of a paint roller.
- Always start at one end of the siding, not the middle.
- Coat your roller
- Roll quickly with even pressure along the panel siding
- Roll backwards in the opposite direction.
- Be careful of timing: Quit two-hours before sundown to avoid bugs and condensation settling on wet paint. Finish a whole wall or other complete section to avoid lasting visible paint lines.
- If you’re seeing lines in your paintwork then you are painting too slowly. Lines are caused by dry paint being overpainted. To avoid lines paint whole panels without pausing.
- If bumps occur after the first coat gently sand the area when dry before applying the second coat.
Should I Hire Professionals? Professionals bring the best equipment, knowledge and experience. Painting Aluminum Siding needs to be done right. It comes down to cost and whether or not you have the confidence to DIY.
Why do you recommend only one type of paint? When I seek advice about anything I go to the best people. I often find that they do the same job the same way using the same materials over and again because that’s what works best, especially when time, money and your reputation are at stake. Just give me the best!