Aluminium window problems are easier to solve when the symptom is separated from the cause. A draught can come from a seal, adjustment, trickle vent, or perimeter junction. Water may enter through the frame-to-wall detail rather than the window itself. Condensation can form on the room side of otherwise sound glass.
Quick diagnostic table
| Symptom | Checks to make | Typical next step |
|---|---|---|
| Window is stiff or will not close | Debris, hinge condition, handle and gearbox, alignment, damaged seals | Clean and inspect; avoid forcing the handle. |
| Draught around opening sash | Seal compression, adjustment, locking points, trickle vent position | Identify the air path before replacing seals. |
| Water after rain | Drainage slots, external seals, cill, frame-to-wall junction, exposure | Trace the highest point of entry and preserve drainage. |
| Mist between panes | Condensation is enclosed within the sealed glass unit | Assess replacement of the glazing unit. |
| Room-side condensation | Humidity, ventilation, glass temperature, room use | Review moisture and ventilation; see the ventilation guide. |
| Chips, chalking, or corrosion | Finish type, exposure, contamination, depth of damage | Specialist coating assessment or replacement. |
1. Stiff opening, closing, or locking
Do not force a handle. First clean accessible tracks and drainage areas using a soft brush. Check for displaced seals, loose fixings, visible hinge damage, or an opening sash that no longer sits square. Lubrication must be suitable for the hardware and should never be used to disguise a damaged gearbox or misalignment.
2. Draughts and whistling
Use a calm day to identify where air is entering. Trickle vents are designed air paths, while leakage at corners, gaskets, or the frame-to-wall junction may indicate adjustment, seal, or installation issues. Replacing a gasket without matching its profile and compression can make performance worse.
3. Water ingress
Keep designed drainage slots clear. Do not seal over them. Inspect external perimeter joints, cills, and interfaces above the opening because water can travel behind finishes before appearing inside. Repeated leaks should be investigated during suitable weather rather than covered with another surface bead.
4. Condensation and misted glass
Condensation on the room side points to a combination of indoor moisture, ventilation, and surface temperature. Misting trapped between panes usually indicates sealed-unit failure. Our home ventilation guide explains how windows, trickle vents, purge ventilation, and extraction work together.
5. Finish damage and corrosion
Wash frames with a mild, compatible cleaner and avoid abrasive pads. Local chips should be assessed before corrosion spreads beneath the finish. Coastal and polluted environments may need a more frequent cleaning regime. For cosmetic refurbishment, read can aluminium windows be painted?
Repair or replace?
Repair is often sensible for an isolated handle, hinge, gasket, or sealed glass unit when the frame and installation remain sound. Replacement deserves consideration when faults are repeated across several openings, sections are distorted or corroded, critical parts are obsolete, or the project also needs a significant improvement in glazing, security, air tightness, or sightlines.
For a structured comparison, use the aluminium window repair or replacement guide. To discuss a measured replacement, browse aluminium windows or request a quotation.
Frequently asked questions
Can I replace aluminium window seals myself?
Only when the exact compatible profile and fitting method are known. The wrong gasket can prevent closing or fail to provide the intended compression.
Why does the window leak only in wind-driven rain?
Pressure and exposure can reveal weaknesses that ordinary rain does not. Drainage, seals, cills, and perimeter installation details should be assessed together.
Is condensation a warranty fault?
Room-side condensation is commonly an indoor humidity and ventilation issue. Moisture trapped inside a sealed unit is different and should be assessed against the unit warranty.
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