Can You Paint Aluminium Window Frames? A Guide for Doncaster Homes
Walk through Doncaster, Doncaster East or Templestowe and look at the windows. On most of the brick veneer and rendered homes built through the 1970s and 80s they are aluminium, and on a large share of those they are the bronze or dark brown anodised frames that were the standard choice at the time. That leaves a lot of Manningham homeowners asking the same question when the exterior comes up for a repaint: can the aluminium be painted too, or do the windows have to be replaced to change the colour?
The short answer is yes, aluminium frames can be painted, and done properly the finish holds up well. The longer answer is that aluminium is one of the least forgiving surfaces a painter works on, and most failures come from treating it like timber.
Why aluminium is different
Aluminium does not absorb anything. Paint on timber gets a grip on the fibres; paint on aluminium sits on a hard, non-porous skin and relies entirely on the preparation underneath it and the primer chosen. Anodised frames add another layer of difficulty, because anodising is a sealed oxide finish that was designed specifically not to let anything stick to it. Powder-coated frames, which are more common on homes built from the 1990s onward and on newer replacement windows, are a baked-on coating that is tough but very smooth.
On top of that, aluminium expands and contracts noticeably with temperature. A north or west-facing frame on a Doncaster ridge-top block can be cold at dawn and too hot to touch by mid-afternoon in summer. A coating that was not bonded properly simply lets go at the edges once that cycle has run through a few seasons.
What proper preparation involves
The first stage is cleaning, and it is more thorough than it sounds. Decades of grime, oxidation and the chalky white bloom that old anodising develops all have to come off, because anything left behind is what the paint ends up bonded to instead of the frame. That means a degreasing wash, a rinse and a full dry.
The second stage is creating a key. The surface is abraded by hand or with a fine abrasive pad so the primer has something to grip, and then it is cleaned again to remove every trace of dust. On anodised frames this step cannot be skipped, because a primer applied straight over intact anodising will peel off in sheets.
The third stage is the primer, and this is where most of the difference between a lasting finish and a failing one is decided. Keyed aluminium needs a primer formulated for non-ferrous metal, typically an etch primer or a dedicated adhesion primer for metals and powder coatings. A general purpose undercoat is not the same thing, and it is the usual reason a painted frame starts lifting within a year or two.
Once the primer has cured, the topcoats go on. The frames, the glazing beads and the sills are all coated, and the finish is built in thin, even coats rather than one heavy one, because thick paint on a frame interferes with the opening sashes and tracks.
Sliding doors, tracks and moving parts
A lot of Manningham homes have aluminium sliding doors onto a patio or deck as well as the windows, and the same approach applies, with one extra caution. The tracks and rollers should be masked rather than painted. Paint in a track wears through quickly, makes the door stiff, and ends up looking worse than the original metal. Opening sashes, awning windows and the moving parts of sliding windows are coated with the frame but with care around the seals and contact points, and they are left open to cure before being closed again.
Spray or brush
Aluminium frames are one of the surfaces where spraying genuinely produces a better result than brushing, because the finish is smooth and there are no brush marks to show. On an occupied home that means thorough masking of the glass, the brickwork or render around the frame and anything nearby, which is one reason the job is often scheduled as part of a full exterior house painting job when the masking and access are already set up.
Colour and the rest of the house
Changing the frame colour is often the point of the exercise. On a 1980s Doncaster brick veneer, taking the frames from bronze to a crisp off-white, a soft grey or a deep charcoal changes the look of the facade as much as the wall colour does. It also opens up choices for the eaves, fascia and garage door that never worked against brown frames. It is worth deciding the frame colour and the wall colour at the same time rather than one after the other.
One caution on dark colours. Deep charcoal and black frames are popular, but a dark coating on a north or west-facing aluminium frame runs very hot in a Melbourne summer. On a frame that is still in good condition that is manageable with a suitable exterior system; on older frames with tired seals it is worth talking through before committing.
When painting is not the answer
Painting restores the look of a frame. It does not fix a frame that is failing. Windows with corroded sills, badly pitted frames where the anodising has broken down, seals that have perished or sashes that no longer run on their tracks will still have those problems under new paint. If the frames are structurally sound and the glass and seals are in reasonable shape, repainting is usually a sensible decision. If the windows themselves have reached the end of their life, replacement is the better spend and painting the old ones is money wasted.
Fitting it into an exterior repaint
On most Doncaster and Templestowe homes the windows are repainted as part of a wider exterior repaint rather than as a standalone job, because the access, the masking and the cleaning down are shared with the walls, the weatherboard, eaves and fascia work and the roofline. Doing them in the same visit means the whole facade is finished to the same standard and the same colour scheme at once, and it is usually cheaper than coming back for the frames separately.
If you are planning a repaint and want to know whether your aluminium frames are worth painting, we are happy to look at them during the free on-site inspection and give you a straight answer along with the quote.