Painting aluminium joinery, window frames, door frames, and other aluminium fittings, is entirely possible, but it needs a different approach to painting wood. Aluminium is naturally smooth and non-porous, meaning paint doesn’t grip it the same way it grips timber, so proper preparation is the difference between a paint job that lasts for years and one that starts peeling within months.
This guide walks through exactly how to paint aluminium joinery properly, whether you’re doing it yourself or deciding if it’s a job worth hiring a professional for. We’ll also touch on how aluminium differs from wood joinery, since understanding that difference explains why the process looks the way it does.
Why Aluminium Joinery Needs a Different Approach to Wood
Before getting into the steps, it helps to understand why aluminium behaves so differently to timber when it comes to painting. Wood is porous, meaning paint and primer can soak slightly into the surface fibres, creating a strong mechanical bond.
Aluminium is completely non-porous and naturally smooth, which means paint sits purely on the surface rather than gripping into it. On top of that, aluminium often has a factory-applied coating or natural oxide layer that actively resists adhesion, which is exactly why skipping preparation steps leads to paint peeling or flaking far sooner than it would on wood.
Aluminium joinery is also generally more resistant to rot, warping, and moisture damage than wood, which is one of the reasons it’s popular for windows and doors in the first place. But that same smooth, weather resistant surface is precisely what makes proper surface preparation so essential before paint will actually stick to it long term.
It’s worth understanding, too, that this isn’t just a theoretical concern. The vast majority of failed aluminium paint jobs we see or hear about come down to preparation being rushed or skipped entirely, rather than a poor quality paint being used. In other words, the paint itself is rarely the weak link. The surface it’s being asked to grip onto usually is, unless it’s been properly prepared first.
What You’ll Need
Before starting, gather the right materials for the job:
- Mild detergent and water (for cleaning)
- Fine grit sandpaper (around 320 to 400 grit) or an abrasive scouring pad
- A cloth or degreasing wipe (methylated spirits or a proprietary degreaser works well)
- A specialist etch primer designed for metal surfaces
- A high quality exterior metal paint, ideally one designed specifically for aluminium or general metal surfaces
- Painter’s tape for masking off glass, seals, and surrounding areas
- A good quality brush or fine foam roller, depending on the finish you want
Having everything ready before you start matters more than it might seem. Once you begin sanding and degreasing a section, you don’t want to be stopping halfway through to find the right grade of sandpaper or realise the primer you bought isn’t actually designed for metal. Laying everything out in advance also makes it easier to work through each frame methodically, rather than rushing steps because momentum has already been lost.
Step-by-Step: How to Paint Aluminium Joinery
1. Clean the Surface Thoroughly
Start by washing the aluminium down with mild detergent and water to remove dirt, grime, and any general surface residue. Rinse well and allow the surface to dry completely before moving on. Any dirt or grease left behind will sit underneath the paint and cause it to fail early, so this step is worth doing properly rather than rushing through it.
2. Degrease the Surface
Even after washing, aluminium often holds onto invisible traces of grease or oils, particularly around handles, hinges, or areas that get touched frequently. Wipe the surface down with a degreasing solution or methylated spirits on a clean cloth. This step is easy to skip, but it makes a real difference to how well the primer bonds afterwards.
3. Lightly Sand the Surface
Using fine grit sandpaper or an abrasive pad, lightly key the surface all over. You’re not trying to remove material, just create a slightly roughened texture that gives the primer something to physically grip onto, since a perfectly smooth surface gives paint very little to hold on to. Wipe away any dust afterwards with a clean, dry cloth.
4. Mask Off Areas You Don’t Want Painted
Use painter’s tape to carefully mask off glass, rubber seals, hinges, and any hardware you want to protect from paint. Aluminium window and door frames often have seals nearby that shouldn’t be painted over, since this can affect how well they function afterwards.
5. Apply an Etch Primer
This step is the one people skip most often, and it’s usually the reason a paint job on aluminium fails early. A specialist etch primer is designed specifically to bond to smooth, non-porous metal surfaces, effectively giving your topcoat paint something reliable to hold onto. Apply it in thin, even coats following the manufacturer’s instructions, and allow it to fully cure before moving on.
6. Apply Your Topcoat Paint
Once the primer has properly cured, apply your chosen exterior metal paint in thin, even coats, allowing proper drying time between coats as specified by the manufacturer. Two thin coats generally give a more durable, even finish than one thick coat, which can crack or peel more easily over time.
7. Allow Full Curing Time Before Use
Even once the paint feels dry to the touch, it often needs longer to fully cure and reach its proper hardness and durability. Avoid heavy use, cleaning, or exposure to harsh weather during this curing period if possible, since paint is generally more vulnerable to damage before it’s fully hardened.
Patience at this final stage matters more than people expect. It can be tempting to treat a frame as finished the moment it’s dry to the touch, but full curing is a genuinely separate process from surface drying, and the two shouldn’t be confused. Rushing use or cleaning during this window is one of the more common, avoidable reasons a fresh paint job ends up marked or damaged within its first few weeks.
Common Mistakes That Cause Paint to Fail on Aluminium
| Mistake | Why It Causes Problems |
| Skipping the degreasing step | Grease residue prevents primer from bonding properly |
| Not sanding the surface | Paint has nothing to physically grip on a smooth surface |
| Using a standard wood or wall primer | These aren’t designed to bond with metal and will fail early |
| Applying paint in cold or damp conditions | Poor curing leads to a weaker, less durable finish |
| Rushing coats without proper drying time | Traps moisture and weakens the overall paint layer |
Almost every one of these mistakes comes down to impatience rather than a lack of skill. None of the individual steps involved in painting aluminium are especially difficult on their own; the challenge is resisting the temptation to shortcut them, particularly the ones, like degreasing and priming, that don’t visibly change how the surface looks before you move on to the next stage.
Should You Paint Aluminium Joinery Yourself, or Hire a Professional?
This genuinely depends on the scope of the job and your comfort with the preparation steps involved. Painting a small section, like a single door frame, is a realistic DIY project for most people, provided the preparation steps above are followed carefully.
Larger jobs, like multiple window frames across a whole property, or aluminium joinery in hard to reach or high locations, are often better suited to a professional, both for the quality of the finish and for practical access and safety reasons.
It’s also worth thinking honestly about how much preparation work you’re realistically willing to put in across several frames. A single door frame done carefully is a manageable weekend project.
Multiplying that same level of care across a dozen window frames, some of which might be at height or in awkward positions, is a very different scale of task, and this is usually the point where hiring a professional starts to make more practical sense.
Rough Cost Guide: DIY vs Professional
As a general guide, since costs vary depending on location and the specific products used:
- DIY materials for a single door or window frame, including primer, paint, sandpaper, and basic tools, typically represent the lowest overall cost, though your time and effort are the trade-off
- Hiring a professional for a small job, like one or two frames, costs more than DIY materials alone but adds proper preparation, experience, and a more consistent finish
- Larger professional jobs, covering multiple windows and doors across a property, cost more overall but often work out more cost-effective per frame, and reduce the risk of an uneven finish or early paint failure from inconsistent preparation
Every property is different, so the best way to understand what’s realistic for your own aluminium joinery is to get a proper quote based on the number of frames, their condition, and how accessible they are.
How Aluminium Joinery Compares to Wood Joinery
Since aluminium and wood are quite different materials to work with, it’s worth understanding a few key differences if you’re more familiar with wood joinery:
- Durability against weather. Aluminium naturally resists rot, warping, and moisture damage far better than untreated wood, though wood treated and finished properly can also last for decades.
- Maintenance needs. Aluminium generally needs less regular maintenance than wood, though repainting is still occasionally needed to refresh the finish or change the colour.
- Sealant and weatherproofing. Aluminium frames rely heavily on rubber seals and gaskets to stay weatherproof, which need to be protected during any painting work, whereas wood joinery relies more on the finish and joinery itself to manage moisture.
- Repair approach. Damaged wood joinery can often be repaired or replaced section by section, while damaged aluminium sections are more commonly replaced as a whole unit rather than repaired locally.
This comparison is a useful reminder that neither material is simply “better” than the other. Aluminium tends to demand less ongoing maintenance overall, but when it does need attention, such as a full repaint, the preparation requirements are more exacting than they are for wood, precisely because the surface doesn’t naturally accept paint the way timber does.
Frequently Asked Questions
Can any paint be used on aluminium joinery?
Not reliably. Standard wall or wood paints aren’t designed to bond with metal surfaces and will likely peel or flake relatively quickly. A specialist metal paint, applied over a proper etch primer, gives a far more durable, long lasting result.
Do I need to remove old paint before repainting aluminium?
If the existing paint is sound, well bonded, and not flaking, you can generally clean, degrease, and lightly sand it before repainting. If old paint is peeling or flaking, it’s worth removing the loose sections first so the new paint has a stable surface to bond to.
How long does painted aluminium joinery typically last before needing a repaint?
This varies depending on the paint quality, preparation, and weather exposure, but a properly prepared and painted aluminium surface can often go many years before needing attention again, especially compared to a rushed job without proper primer.
Can aluminium joinery be painted a different colour to match a home renovation?
Yes, this is actually one of the more common reasons people repaint aluminium windows and doors, refreshing the colour to match a new exterior scheme without replacing the frames entirely.
Is it worth painting aluminium joinery myself to save money?
For smaller, accessible jobs, DIY can be a reasonable option if you’re prepared to follow the preparation steps properly. For larger properties or hard to reach frames, a professional finish is often more cost-effective in the long run, since poor preparation can mean redoing the work sooner than expected.
Does weather affect how well paint sets on aluminium?
Yes, significantly. Painting in cold, damp, or very humid conditions can prevent paint and primer from curing properly, leading to a weaker, less durable finish. Dry, mild conditions generally give the best results.
Can I speed up the curing process to use the frames sooner?
It’s best not to try. Curing depends on a chemical process within the paint itself, which happens on its own timescale regardless of surface conditions. Attempting to force it, with heat or by handling the surface too soon, generally weakens the finish rather than speeding up genuine hardness.
If you’re planning a larger repainting project across several aluminium frames, or you’re unsure whether a frame’s existing finish is sound enough to paint over directly, it’s worth getting an assessment before starting, so the preparation work matches what your specific frames actually need.