Aluminium frames last a long time, which is why replacing one often feels premature. Sometimes it is. Other times a repair is money spent on something that will fail again within a year.
Here is how the decision usually breaks down.
Worth Repairing
Failed corner joints. The mitred corners are the weak point on most frames. Where a joint has opened but the sections themselves are sound, it can be rewelded or reinforced. This is common on older frames and a straightforward fix.
Cracks from impact or stress. A localised crack in otherwise good material can be welded. Aluminium welding needs care – see why aluminium welds crack – but a clean repair holds.
Seized or worn hardware. Hinges, stays, handles and rollers are replaceable items. A window that will not open smoothly usually needs hardware, not a new frame.
Failed seals. Draughts and leaks are frequently a gasket problem rather than a frame problem, and gaskets are cheap.
Usually Better to Replace
Widespread pitting corrosion. Aluminium does not rust, but in coastal air it pits – white powdery spots that eat into the surface. Isolated pitting is cosmetic. Once it is widespread and deep, the section has lost material and welding onto compromised metal does not hold.
Warped or twisted sections. A frame that has distorted will never seal properly again. Straightening aluminium reliably is difficult, and a frame that does not seal defeats its purpose.
Obsolete profile systems. If the frame uses a discontinued profile and the hardware is no longer available, ongoing repairs get progressively harder and more expensive.
Multiple failures at once. Corners going, hardware worn, seals gone, some corrosion – individually each is repairable, together they signal a frame at the end of its life.
The Coastal Factor
Proximity to the sea shortens the repair-versus-replace calculation considerably. Salt air accelerates pitting, and a frame that would last decades inland can show significant deterioration much sooner on an exposed coastal elevation.
Anodised and powder-coated finishes protect the aluminium underneath. Once that finish is breached, deterioration accelerates. See maintaining metal in a coastal climate.
What to Check First
Look at the corners, press gently on the frame to see whether it flexes at the joints, check for white powdery deposits, and try the window through its full range of movement. Those four checks establish most of what you need to know.
For related reading, see signs it is time to replace old windows, aluminium doors and windows, and custom aluminium frames.
Frequently Asked Questions
Can a cracked aluminium window frame be welded?
Often yes, provided the surrounding material is sound. The area is cleaned back to bright metal and welded with the correct filler. Where the section has thinned through corrosion, welding will not hold and replacement is the better route.
What are the white powdery marks on my aluminium frames?
That is aluminium oxide from pitting corrosion, common in coastal areas where salt sits on the surface. Light deposits are cosmetic and can be cleaned; deep pitting means the section has lost material.
Is it cheaper to repair or replace an aluminium window?
A single fault – one corner, worn hardware, a perished seal – is almost always cheaper to repair. Once several faults appear together, or the section is corroded through, replacement usually costs less than repeated repairs.
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