Aluminum chalks for a different reason than vinyl does, and the decision at the end is different too. How to test what you have, what a restoration wash actually achieves, and when paint is the honest answer.
Aluminum siding is metal with a baked enamel finish on it. That finish is doing all of the work: the colour, the weather resistance, the look. Ultraviolet light gradually breaks down the resin binding the pigment, and the pigment that is no longer bound sits loose on the surface as a fine powder. Run your hand along a sunny wall and it comes away coloured.
This is not the same as what happens to vinyl, even though the symptom looks identical. Vinyl is pigmented plastic, so what chalks is the material itself degrading. Aluminum is a coating failing on a substrate that is completely fine underneath. That distinction is the whole reason the decision at the end of this page is different.
Most aluminum siding in the Triangle and Johnston County went up between the 1960s and the early 1980s, which means the finish on a lot of it is forty to sixty years old. It was never expected to last that long. Around older parts of Smithfield, Selma, and the established streets in Clayton, chalked aluminum is extremely common and almost always well past the point where the coating was doing anything.
| Test | Aluminum | Vinyl |
|---|---|---|
| Tap it | A metallic ring, thin and hard | A dull plastic sound |
| Look at a cut edge or a corner | A visible metal edge, often dented rather than cracked | Thicker, uniform colour through the material |
| Check for dents | Dents from hail and ladders. Aluminum dents | Vinyl cracks or holes instead. It does not dent |
| Magnet | Does not stick. Aluminum is not magnetic, but steel siding is, and steel exists too | Does not stick |
| What the chalk looks like | The colour of the siding, because it is pigment | Chalky white regardless of the siding colour |
If you are not sure, take a photo of a cut end, an outside corner, and a wall in sunlight, and send them. We can identify it from that and it changes what we would recommend.
A soft wash removes what is sitting on the siding: algae, mildew, dirt, pollen. Chalk is also sitting on the siding, so a wash removes the loose layer of it, and the wall genuinely looks better.
What it does not do is stop the process. Under the chalk you removed is more degraded finish, which becomes the next chalk. On a heavily chalked wall, a plain wash can also make things look worse for a while, because it takes the powder off unevenly and leaves the shaded sections looking darker than the sunny ones.
That is why oxidation removal is a separate job from house washing rather than a stronger version of it.
Algae and dirt come off before anything else, because you cannot judge chalk through a layer of growth. The shaded walls usually need this more than the chalked sunny ones do.
An oxidation remover is applied and worked panel by panel. This is hand and brush work; pressure is not the active ingredient and never has been.
The goal is an even surface across the whole elevation, which matters more than any individual patch. A wall that is partly restored looks worse than one that is uniformly faded.
Loose pigment has to leave rather than dry back onto the wall.
A protectant or wax-type product slows the return. It is an add-on, it is not permanent, and a company that describes it as permanent is overselling.
The honest expectation: on siding that is chalked but not destroyed, this is a substantial improvement that people are genuinely pleased with, and the chalking starts again over the following year or two. It buys you time and appearance. It does not replace the finish, because nothing short of paint does.
This is the actual question, and unlike with vinyl there is a good middle answer.
Right when the chalk is moderate, the colour is still broadly even, the panels are sound, and you are not ready to spend on paint. Cheapest option, repeatable, and it buys several years.
Right when the finish is thoroughly gone, the colour is blotchy, or you want a different colour. Aluminum takes paint very well with proper prep, and prep means exactly the dechalking described above. A wash is not enough and a painter who skips it will be back.
Right when panels are badly dented, seams are failing, there is corrosion at the fixings, or you are insulating and residing anyway. Replacing structurally sound aluminum purely because it is chalky is usually spending siding money on a paint problem.
The sequence matters if you are painting. Clean, dechalk, then paint. Paint applied over chalk is bonding to loose powder, and it will peel in sheets within a few years no matter how good the paint was. This is the most common cause of failed siding paint jobs and it is entirely a prep failure.
Aluminum is rarely alone. Gutters, downspouts, fascia wrap, soffit, window wraps, garage doors, and metal awnings all chalk on the same schedule and all respond to the same treatment. Doing the siding and leaving chalked white gutters above it is a common and very visible half-job, so it is worth pricing the gutters in at the same time.
Tiger striping on gutters, which is the vertical dark streaking on the face, is a related but different problem: it is a film of oxidised finish holding dirt, and it needs its own product rather than the general wash.
We will tell you which of the three it is. If the siding is far enough gone that a restoration would be a waste of your money, we say so, because the alternative is taking payment for a result we already know will disappoint you. If it is a good candidate, we will show you a test panel before committing to the whole elevation, so you are deciding on the actual result rather than on a description of it.
Send a photo of a sunny wall and a shaded one, or call (919) 698-3669 and we will come and look. Oxidation removal is one of the things we do most around here, and it is one of the few jobs where the answer is sometimes do not bother.
“They brought the color back on our vinyl siding after another company left it chalky. Night and day.”
“They transformed the outside of our house. The siding looks brand new and they were careful around all my flower beds.”
“Same-day service and the whole property looks better. Will use them every year.”
What a multifamily property actually needs cleaned, how often, and why the surfaces that generate complaints are almost never the ones in the budget.
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Read the guide →We fly the roofline and show you the footage on the spot. You see your own gutters, joints, and downspouts on the screen instead of taking our word for it. It costs nothing and you are not committing to the cleaning.
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