Window Frame Repair in Dunedin – Aluminium & Timber Frames Repaired and Resealed

Frames fail differently depending on what they are made of and where in the city they sit. Timber goes at the sill once the paint film breaks. Aluminium corrodes at the corners and around the fixings, fastest within a few hundred metres of the water on the south coast and up the harbour. uPVC goes brittle under UV. Knowing which one is in front of you decides whether the fix takes an hour or a week.

Finding the leak before sealing anything

A wet internal sill has several possible causes and only one of them is the seal. Blocked drainage backs water up over the frame. A failed head flashing lets water in above the window and it appears at the bottom. Perished glazing wedge lets water past the glass. A racked sash leaves a gap at one corner.

We water test in stages, bottom up, until the leak shows itself. Running silicone around the outside of a window without knowing why it leaks is the most common bad repair we get called out to undo, because it traps the water inside the frame instead of letting it drain.

Timber frame repair

Rot follows the water. The sill first, then the bottom of the jambs, then the bottom rail of the sash. Everything above that is usually sound old growth timber worth keeping.

We cut back to solid wood, scarf in new timber, glue and pin it, shape it to the original profile and prime it before it leaves. Where a sill has gone completely, a full sill replacement into the existing frame still costs far less than new joinery.

Aluminium corrosion and racked sashes

Aluminium frames rarely fail structurally. What fails is the corner joints, the fixings and the coating. Open corners let water track into the wall rather than the room, which is worse and harder to spot. Chalky white bloom means the powder coat has been breached.

Sashes that catch on the frame or leave a triangular gap have usually dropped rather than warped, and that comes back to worn hinges, stays or rollers. New hardware and a resquare fixes the gap. Replacing the window because it will not close properly is the expensive way to solve a hardware problem.

When replacement is the honest answer

Pitting right through the aluminium. Timber that is soft through the full section rather than just at the face. Corners open so far the frame is no longer square. uPVC gone chalky and brittle enough to crack when you screw into it.

In those cases we quote the replacement and explain why. What we will not do is quote a replacement on a frame with fifteen good years left in it because it is the bigger invoice.

Diagnosing a frame before quoting it

Square, straight and tight

Three checks tell you most of what you need. Is the frame square, measured corner to corner. Is the sill straight along its length. Are the corner joints tight when you press them.

A frame that passes all three is worth repairing almost regardless of how it looks, because coating and hardware are surface problems.

When to stop

Aluminium pitting through the extrusion, timber soft through the full section rather than at the face, corners opened far enough that the frame has racked, or uPVC gone chalky enough to crack when a screw goes in.

Those are the four we will tell you to replace, and you get both prices with the reasoning rather than just the bigger number.

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 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 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.

Repairing timber and aluminium frames in Dunedin

Frame repair covers two very different materials with two very different failure modes.

Timber rot is cut out, not filled

Decayed timber is cut back to sound material and new heartwood is scarfed in, glued and fixed. It is slower than filler and it is the only version that lasts, because filler bridges the problem rather than removing it.

Aluminium corrosion and distortion

Pitting from salt exposure, and section distorted by building movement or forced entry. Minor corrosion can be treated and sealed. A distorted section that no longer holds a seal is a replacement.

The reveal and the flashing behind

A frame that keeps rotting usually has a flashing problem behind it. Repairing the visible timber without correcting the water path repeats the failure, so we look behind before quoting.

Cost and sequence on a Dunedin frame repair

Frame work is the one part of this trade where the quote genuinely cannot be fully fixed until the opening is exposed.

We quote an allowance and show the rate

The visible repair is priced. Hidden decay is carried as an allowance with a stated rate, so if we find nothing you pay nothing and if we find something you already know the number.

Repair before reglazing, always

New glass in a rotten frame is money in the wrong order. Where both are needed the frame is made sound first, then the glass goes back in.

Painting and protection

Bare repaired timber gets primed before we leave, even where the finish coat is somebody else's scope. Unprimed timber through one wet week undoes the repair.

Window Frame Repair at a glance

Materials

Aluminium, timber, uPVC and composite frames

Leak testing

Water tested bottom up, cause identified before any sealing

Timber repairs

Scarf repair, bottom rail replacement, full sill replacement

Aluminium repairs

Corner joints resealed, coating restored, hardware replaced

Sash squaring

Hinges, stays and rollers replaced, sash rehung and adjusted

Finish

Timber primed ready for paint, aluminium touched up to colour

Assessment

Repair and replacement priced side by side on the same quote