Aluminum siding doesn't rot, so most of its problems are cosmetic: dents, chalky or faded paint, and the occasional loose panel. Isolated dents and damaged panels can be repaired, and chalky, faded siding can be washed and repainted with a good exterior acrylic paint if it is prepped correctly. Replacement makes more sense when damage is widespread, panels can't be matched, or you suspect water problems in the wall behind. Most aluminum siding on houses today was installed between the 1940s and the 1970s, and InterNACHI's life expectancy chart lists aluminum siding at 25 to 40-plus years.
Common aluminum siding problems and fixes
| Problem | What you see | Usual fix |
|---|---|---|
| Dents | Dings from ladders, balls, hail or impacts | Fill small dents; replace badly creased sections |
| Chalking | White or colored powder rubs off on your hand | Wash thoroughly, then repaint |
| Fading | Uneven color, especially on sunny walls | Repaint |
| Scratches | Bare metal showing through the finish | Clean and touch up, or repaint the wall |
| Corrosion | White, powdery spots or pitting, often near the coast or where other metals touch it | Clean and spot-treat; replace panels with deep pitting |
| Loose or rattling panels | Panels that move or have slipped out of their lock | Re-secure; check what is behind first |
| Water stains or soft trim | Streaks below windows, soft sills or trim | Find the leak; may mean opening the wall |
A short history, and why it matters
Aluminum siding was being produced for homes by the 1940s. Alside, one of the early makers, says its founder introduced the first residential baked-enamel aluminum siding in 1947. InterNACHI notes that it went on many affordable homes through the 1970s, and its use declined after the energy crisis, as vinyl took over the market. Alside itself entered the vinyl siding business in 1979.
Two practical consequences follow. First, much aluminum siding is now several decades old, so its factory finish is often chalking or faded. Second, aluminum was often installed over a house's original wood siding to avoid painting. What is underneath can be in any condition, and on houses built before 1978 the original paint underneath may contain lead.
Repairing aluminum siding
Dents
Small, shallow dents are usually filled and sanded smooth with a filler suited to metal, then primed and painted. Deep creases or torn metal are better handled by replacing that section of panel. Insulation board behind the panels, where it exists, helps them resist new dents.
Replacing a damaged section
A damaged length of panel can be cut out and a new piece fitted in, overlapping the neighbors and secured with sealant or adhesive. The hard part is finding a matching profile. Many owners take replacement pieces from a hidden spot, such as behind a shrub or inside a garage wall, and patch the hidden spot with a non-matching piece. Once the whole wall is repainted, small color differences disappear.
Loose panels
Panels that have slipped out of their locks can often be re-engaged and fastened. If many panels are loose, check the wall behind before re-securing them; soft sheathing or framing will not hold fasteners.
Grounding
Metal siding conducts electricity, and InterNACHI notes that some jurisdictions require it to be grounded as a safety measure. If you are doing electrical work on the outside of the house, or wiring has been damaged near the siding, have an electrician check it.
Painting aluminum siding
Painting is the most cost-effective way to refresh sound aluminum siding. The prep matters more than the paint. Sherwin-Williams' published guidance for aluminum siding is a good baseline:
- Wash it. Clean the siding with the correct detergent to remove chalk, oil and other contaminants. On older siding this is the most important step: paint applied over chalk peels.
- Check for chalk. After it dries, rub a hand or dark cloth across the surface. If powder comes off, wash again.
- Deal with mildew and corrosion. Treat mildew on shaded walls, and clean any corrosion spots. Ask your paint supplier whether bare or corroded spots need a metal primer.
- Prime only if needed. Sherwin-Williams notes that unless it has a very slick surface, aluminum siding rarely needs to be primed.
- Apply a quality exterior acrylic latex. Brush, roll or spray. A satin sheen gives the closest look to a factory finish and hides dents better than gloss.
Paint only in dry weather within the temperature range on the paint label. On hot inland walls in Concord, Livermore or San Jose, avoid painting surfaces in direct afternoon sun. InterNACHI estimates aluminum siding may need repainting every five to ten years; sunny walls and coastal exposures fade faster. For more on how paint ages on different walls, read our guide to siding paint fading, and see siding colors if you are changing color.
What drives the cost of each option
We don't publish prices, but the three options scale differently:
- Repairs are priced mostly by labor and the number of spots. A handful of dents is a small job; matching and replacing sections across several walls adds up quickly.
- Painting depends on wall area, stories and access, how much washing and chalk removal the siding needs, and how much trim and window masking is involved. Two-story walls need ladders or scaffolding.
- Replacement adds tear-off, disposal, any sheathing repair, a new weather barrier and flashing, trim, and the new siding. If the original wood siding underneath comes off too, disposal and lead-safe work on pre-1978 homes add to it.
If the panels are sound, painting usually costs far less than re-siding. The gap narrows when you add up repeated repaints over the years, or when the house also needs windows and has water damage that only shows once the wall is open.
When replacement makes more sense
- Dents, creases or corrosion cover large areas, and repaint would only highlight them.
- You can't find matching panels for the repairs you need.
- There are signs of water inside: stains below windows, soft trim, or musty walls.
- You are planning new windows. Re-siding at the same time lets the windows be flashed properly.
- Your lot is in a Fire Hazard Severity Zone, and you want to update the wall, vents and eaves together.
When aluminum comes off, decide whether to remove the original siding underneath too. Removing both layers exposes the sheathing and weather barrier so damage can be found and fixed. On pre-1978 homes, removing painted wood siding requires lead-safe work practices.
Replacement options
- Fiber cement such as James Hardie gives a painted lap look, doesn't dent as easily as thin metal, and is noncombustible when tested to ASTM E136. See our Hardie board siding guide.
- Vinyl is the lowest-cost option and never needs paint. It is combustible and can distort under concentrated heat. Our vinyl siding cost and lifespan guide covers the trade-offs.
- Engineered wood such as LP SmartSide is light, comes in long lengths and has a cedar texture. It is combustible and needs paint maintenance.
Our siding replacement page explains how we estimate. We give a free written estimate after a walkthrough, and we can price repair, repainting and replacement side by side.
Frequently asked questions
Can aluminum siding be repaired?
Yes. Small dents can be filled and painted, damaged sections can be cut out and replaced, and loose panels can be re-secured. Matching old profiles is the main limit, so replacement pieces are often taken from a hidden area of the house.
Can you paint aluminum siding?
Yes. Wash it thoroughly to remove chalk and dirt, let it dry, and apply a quality exterior acrylic latex. Sherwin-Williams notes that aluminum siding rarely needs primer unless the surface is very slick.
How long does paint last on aluminum siding?
InterNACHI estimates aluminum siding may need repainting every five to ten years. Good prep, especially removing chalk, and a quality acrylic paint push it toward the longer end.
What is under aluminum siding?
Often the house's original wood siding, sometimes with insulation board behind the aluminum. Its condition varies, and on pre-1978 homes the old paint may contain lead.
Should I paint or replace aluminum siding?
Paint it if the panels are mostly straight and sound and there are no signs of water damage. Replace it if damage is widespread, panels can't be matched, or you are replacing windows or suspect leaks in the wall.
Sources
The information provided here is intended for general reference and should not be considered professional advice. Before starting any project, consult a licensed contractor. Product features, specifications, and warranties may have been updated since this was published. Any mention of brands or products reflects personal opinion and does not constitute an endorsement or warranty.
