Aluminium Window Frame Repair in Dunedin – Commercial & Residential Metal Frame Restoration

Aluminium here fails at the corners and the fixings long before the extrusion gives up. On the coast, from St Clair round to Brighton and up the harbour to Port Chalmers, salt drives that and the coating needs washing every three months. Inland it is age plus a frame that has never been cleaned in forty years.

The chalky white bloom is the coating failing, not dirt

White powder on an aluminium frame is aluminium oxide. The powder coat has been breached and the metal underneath is corroding. Wiped early and treated with a non abrasive restorative cleaner made for powder coat, the finish comes back and the frame is fine.

Left long enough it pits, and pitting cannot be polished out. That is the point where a frame stops being repairable, so it is worth acting on the first sign rather than the fifth.

Corner joints let water into the wall, not just the room

Aluminium frames are mitred and joined at the corners with cleats and sealant. Thirty years of thermal movement and Dunedin wind loading opens those joints. Water then tracks into the frame cavity and out the back, where it reaches framing instead of your sill.

We strip the failed sealant, clean the joint properly and reseal with a neutral cure silicone rated for the substrate. It is a small job that prevents a very large one.

Racked sashes are a hardware problem

If a sash leaves a wedge shaped gap or catches on one corner, the frame is almost never bent. Worn hinges, stays or rollers let the sash drop, and the gap follows. Replacing the hardware and rehanging the sash closes it.

What we can save and what we cannot

Surface oxidation against pitting

Chalky white bloom is aluminium oxide sitting on the surface, and at that stage a wash and a restorative cleaner made for powder coat brings the finish back. Run a fingernail across it. If it is smooth under the bloom the frame is fine.

Once you can feel craters, the metal has lost section and no polish puts that back. Frames get to that point surprisingly quickly on the coast, which is why the three monthly wash is not fussiness.

Resealing a corner without pulling the frame

Mitred corners are joined with cleats and sealant. Thirty years of thermal movement opens them, and the water that gets in runs down inside the frame and out the back into framing rather than into the room, which is why nobody notices until there is a stain on the lining.

We cut the failed sealant out, clean the joint back to bare metal and reseal with a neutral cure silicone rated for the substrate. It takes under an hour a corner and it prevents a repair that costs many times more.

How Window and Glass Repair Dunedin diagnoses and repairs in Dunedin

Guessing at a cause is how people pay twice. Window and Glass Repair Dunedin finds the fault before quoting the fix, which sometimes means saying the problem is not the window at all.

1. Inspect the opening as one system

   Frame, sashes, hardware, seals and drainage all get checked together, because a fault in any of them presents identically from inside. Looking only at the obvious part is how the wrong repair gets sold.

2. Separate condensation from water ingress

   In a Dunedin winter this is the single most common diagnostic question. Water on the inside face of the glass, pooling on the sill, worse in the morning and worse in bedrooms, is almost always condensation. Water appearing after rain and tracking from the head is not.

3. Water test where ingress is real

   Controlled water on one zone at a time from the bottom up, with somebody watching inside. It takes an hour and it is the only reliable way to find an entry point rather than resealing everything and hoping.

4. Check the drainage before condemning a seal

   Aluminium frames let water in by design and drain it back out through weep holes in the sill. Blocked weeps present exactly like a failed gasket. Clearing them costs almost nothing, so it gets ruled out first.

5. Report the cause in writing

   You get told what failed, why, and whether it will recur. Where the cause is a head flashing, the cladding above or the way the room is ventilated, Window and Glass Repair Dunedin says so rather than quoting glazing work that cannot fix it.

6. Quote repair against replacement

   Where both are genuine options they go on the same quote with the reasoning. Most windows Window and Glass Repair Dunedin is called to do not need replacing, and you should be able to see the gap between the two numbers yourself.

7. Test again before leaving

   Every sash opened, closed, locked and checked for even seal compression. On a leak repair the opening is water tested a second time to confirm the fix.

Why aluminium window frame repair in Dunedin is its own problem

The housing stock and the climate here combine in a way that produces faults you do not see in warmer cities.

Old joinery that has already moved

A house that has stood since the 1890s has settled, and the openings have gone out of square with it. A sash that will not latch is very often a dropped or racked opening rather than a failed lock, and adjusting is far cheaper than replacing.

Student and rental housing gets harder use

A large share of the older stock is tenanted, which means more cycles on the hardware and more forced sashes. MBIE inspected fifty three Dunedin student rentals in May and June 2026, which gives some sense of how much attention this housing is getting.

Frost and damp accelerate everything

Around fifty ground frost days a year, and a lot of the older stock heated intermittently. Repeated wetting and freezing at the bottom rail is what turns a small paint crack into a rotten sill within a few seasons.

South Dunedin ground is a factor

On the flat, the water table sits close to the surface and moisture frequently rises from the ground rather than condensing from the air. Window and Glass Repair Dunedin checks that before quoting glass that would not fix it.

What aluminium window frame repair costs in Dunedin

Repair pricing looks unpredictable from outside because it depends entirely on what is actually wrong. These are the bands we quote within.

Diagnosis and call out

A standard assessment covers inspecting the opening as a system and giving you a written cause. Where water ingress is suspected, a controlled water test takes about an hour and is the only reliable way to find an entry point rather than resealing everything and hoping.

Hardware and seals

The cheapest end of this trade. Stays, rollers, catches, handles and gaskets are consumables and replacing them is a fraction of what people expect. Most windows Window and Glass Repair Dunedin is called to do not need replacing and the repair typically sits well under a tenth of a new unit.

Glass and sealed units

A broken pane runs $250 to $600 in a common size. A failed double glazed unit replaced in the existing frame runs $350 to $800. In both cases the frame and hardware stay, which is why repair usually wins on a sound window.

When replacement is the honest answer

Corrosion through the section, a frame distorted by building movement, or where the reason for the job is thermal performance rather than a fault. At that point a repair is money spent on a window you will replace anyway, and Window and Glass Repair Dunedin says so.

Repair or replace: how to decide in Dunedin

Four questions that settle it, in the order worth asking them.

Is the frame itself sound

Aluminium frames usually outlive everything attached to them, and timber frames are repairable far more often than they are replaced. If the frame is sound, almost everything else is a consumable and repair is the clear answer.

Is the complaint a fault, or is it the climate

Condensation running down the inside of the glass on a frost morning is not a fault. No repair fixes it and no reglaze fixes it. Ventilation, heating and thermal performance do, which is a different job with a different budget.

What is the whole of life number

A cheap repair on a window you will replace in three years costs the money twice. A repair on a window with twenty years left is the best value work in this trade. Window and Glass Repair Dunedin puts both numbers on the same quote so the gap is visible.

Is the house being sold or tenanted

On a rental, compliance and durability change the calculation, because the window has to keep working through harder use. On a house being sold, a documented repair is often enough and a full replacement rarely returns its cost.

What actually fails on Dunedin aluminium frames

The extrusion itself is durable. What fails is everything attached to it and everything it drains through.

Corner joints opening up

Aluminium frames are mitred and crimped or screwed at the corners with a sealant behind. When that joint opens, water runs into the frame cavity rather than down the face, and it shows up as a leak nowhere near the corner.

Pitting and white bloom near the coast

Salt attacks the anodising or powder coat and the surface blooms. Caught early it is cleaned, treated and sealed. Left, it pits through the section and becomes a replacement.

Distortion from movement or forced entry

A section that has been levered no longer holds a seal along its length. Minor bows can be drawn back. A frame that has yielded cannot be straightened and stay straight.

Commercial and residential frame restoration in Dunedin

The same faults appear in both, and the constraints around fixing them are completely different.

Residential work is sequenced around the household

One opening at a time, secured before we leave each day, and internal linings protected. Most domestic frame repairs are a day or two on site.

Commercial work is sequenced around trading hours

Shopfront and office frame repair is frequently after hours or staged section by section so the building stays secure and usable. We price the access constraint rather than discovering it.

Matching legacy profiles

Joinery systems change and older profiles are discontinued. We can usually source compatible hardware or adapt, and where a section genuinely cannot be matched we say so rather than fitting something that almost fits.

Aluminium Window Frame Repair at a glance

Corner joints

Failed sealant cut out and resealed with neutral cure silicone

Coating

Non abrasive restorative cleaner, never solvents or scouring pads

Fixings

Corroded screws replaced, 316 stainless near the coast

Sash squaring

Hinges, stays and rollers replaced, sash rehung

Drainage

Slots cleared and water tested

When to replace

Pitting through the extrusion, or corners beyond resealing