Rust formation on steel window frames
Steel window frames are common in pre-war homes and buildings from the Amsterdam School period. Where wooden frames suffer from wood rot, steel frames deal with rust — and that calls for a different, specific approach.

Cause
As soon as the protective paint layer is damaged or comes loose, the steel comes into contact with moisture and oxygen, causing rust to form. Rust expands, causing the paint to come loose further, which reinforces the process itself.
How to recognise it
- Brownish-red rust stains showing through the paint layer
- Bubbling or peeling paint at spots with rust
- Rust traces along sealant joints or hinges
What's the risk?
- Untreated rust gradually attacks the steel further
- With prolonged neglect, the structural strength of the frame can decrease
- Rust spreads under the paint layer, even in spots that still look fine from the outside
The solution
We remove rust down to bare, sound steel, treat it with a rust-inhibiting primer, and then build up a durable paint system specifically suited to steel.
For severe deterioration, we advise local repair by a specialized party where needed, before we finish the paintwork.
When painting is enough
For superficial rust stains on an otherwise sound frame, local de-rusting and repainting with a rust-inhibiting system is enough.
When repair is needed
If the steel has already lost thickness or the structure has been weakened, structural repair is needed first before painting.
How Painting Company solves it
- Inspection of the extent of the rust
- De-rusting down to bare steel
- Applying a rust-inhibiting primer
- Building up a durable paint system suitable for steel
Preventing rust formation on steel window frames: practical maintenance
The best way to prevent rust formation on steel window frames is to regularly check the spots where the problem most often starts, and fix small defects straight away instead of waiting. As soon as the protective paint layer is damaged or comes loose, the steel comes into contact with moisture and oxygen, causing rust to form. Rust expands, causing the paint to come loose further, which reinforces the process itself.
A fixed maintenance cycle — for example periodically touching up vulnerable spots such as sealant joints, corners and sills — is often cheaper than waiting until a problem shows up in full. Not sure whether your situation needs attention? A free, no-obligation inspection gives you clarity.
Why choose Painting Company
Painting Company has now completed over 1374 projects and serves more than 261 VvE's, with a team of 14+ permanent painters and an average Google rating of 4.9. With rust formation on steel window frames, it's not just about the visible paint layer but also the structural repair underneath — we have daily experience with exactly that.
As part of CrumBouw and GoedkoopSteigerHuren.nl, we can combine this with window frame painting and, if the situation calls for it, scaffolding — all through a single point of contact. Request a free, no-obligation quote, and we'll think it through with you.
Frequently asked questions about rust formation on steel window frames
Can you treat steel window frames the same way as wooden ones?
No, steel requires different preparation and different products than wood. We use rust-inhibiting primers and paint systems specifically suited to steel.
Is rust on old steel window frames always a big problem?
Not necessarily — with timely detection and treatment it usually stays limited to de-rusting and repainting. Waiting does make the problem bigger.
Can I fix rust formation on steel window frames myself, or is this a job for a professional?
Small, surface-level cases can sometimes be touched up yourself, but if you're unsure we'd advise against it. We remove rust down to bare, sound steel, treat it with a rust-inhibiting primer, and then build up a durable paint system specifically suited to steel. Repairs done incorrectly often end up costing more in the long run than calling a professional painter straight away.
How long does it take to fix rust formation on steel window frames?
That depends a lot on the extent and accessibility of the spot. For a limited, localised case the work is often done within a day or a few days; larger areas take longer. During the free assessment we give a concrete estimate for your situation.
What does it cost to fix rust formation on steel window frames?
That varies by situation — the extent, the accessibility and whether painting is also needed all play a role. We give a clear quote after a free, no-obligation assessment, so you know exactly where you stand beforehand.
What happens if I ignore rust formation on steel window frames?
Untreated rust gradually attacks the steel further The longer you wait, the bigger the eventual repair — and the cost that comes with it — tends to be.
What's the best time of year to have this addressed?
We prefer to carry out exterior work in dry weather at a moderate temperature, usually from spring to autumn. Repairing acute damage — such as cutting out rotten wood — can however often be done year-round, so the problem doesn't get worse while you wait for better weather.
How do I stop rust formation on steel window frames coming back after it's fixed?
We address not just the visible symptom but also the underlying cause — as soon as the protective paint layer is damaged or comes loose, the steel comes into contact with moisture and oxygen, causing rust to form. Rust expands, causing the paint to come loose further, which reinforces the process itself. Periodic maintenance also helps: touching up small damage in time prevents a small problem growing back into a bigger repair.
What materials and techniques do you use for this?
We work with professional materials and paint systems matched to the surface and the load it faces — not standard DIY-store paint. Where needed we combine that with specialised wood repair systems or primers matched to the specific cause.
Do you offer a guarantee on the repair work?
We always discuss guarantee terms upfront and set them out clearly in the quote, so you know exactly what to expect before we start.
Can you combine this with window frame painting?
Yes, we combine this regularly. If we're already on site for window frame painting, it's often more efficient to include this in the same schedule rather than planning it separately.
Is rust formation on steel window frames worse on older or listed buildings?
This comes up more often on older properties, simply because the woodwork and facades have been exposed to the weather for longer and often already carry several layers of paint. On listed-building details we work with extra care to preserve the original profiling and appearance.
How do I spot early signs, before it's visibly bad?
Brownish-red rust stains showing through the paint layer
Is a visual inspection enough, or is more investigation needed?
In most cases a thorough visual inspection by a professional painter is enough to determine the extent. If there's doubt about the underlying structure, we look a little deeper, for example by gently testing whether the wood can still bear weight.
Do you also work on commercial buildings and real estate, not just homes?
Yes. We fix rust formation on steel window frames for private homes, VvE's and real estate such as commercial buildings and apartment blocks. The approach is similar, though larger properties are often planned in phases.
Can rust formation on steel window frames affect the value of my home?
Visible damage to window frames, facades or woodwork can create a negative impression during a sale or valuation and raise questions about deferred maintenance. Addressing it in time avoids that discussion and keeps the property looking well cared for.
Do I need to prepare anything before you come round?
No, that's not necessary. Just make sure the spot is reasonably accessible; we handle everything else, from inspection to execution.
Do you use scaffolding if the spot is high up or hard to reach?
If the situation calls for it, we arrange that through GoedkoopSteigerHuren.nl, part of the same organisation as Painting Company. We combine that into a single request, which saves coordination steps.
How quickly can you come round for an assessment?
We respond to requests quickly and schedule the assessment as soon as possible in consultation with you. Request a free, no-obligation quote and we'll get in touch.
What's the difference between touching up and a full repair?
For superficial rust stains on an otherwise sound frame, local de-rusting and repainting with a rust-inhibiting system is enough. If the steel has already lost thickness or the structure has been weakened, structural repair is needed first before painting.
Ready for your next project?
Request a free, no-obligation quote today. We get in touch, think along with you and deliver the best paintwork for your home, VvE or property.