There's a stubby screwdriver that lives in my ute for one job in particular. Not driving screws. Telling a rotten window from a window that's just been let go.
Because from three metres back on the lawn they look identical. Chalky grey paint, sash that jams in February, putty crumbling out of the rebate. Half the weatherboard houses on the western side of the Illawarra have windows like that, and there's no way to tell from out there whether the timber under the paint is fine or whether it's compost. You press the point in and find out. Takes about four seconds a window.
Thirroul last winter, six windows on the hot side of the house, and a quote sitting on the kitchen bench for aluminium sliders at north of twenty grand because the timber was supposedly gone. Five of the six took the point about a millimetre and stopped, which is sound hardwood under forty years of neglected paint. The sixth went in past the handle. So one window got replaced, the other five got two days of work, and the whole lot came in under a third of that quote.
That's not me being a hero. It's just that tired and rotten look the same from the footpath, and only one of them costs twenty grand to fix.
Where to point the screwdriver
Rot in a timber window is almost never random. Water runs down glass, sits on the bottom of the frame, and works into end grain wherever paint has cracked. So the bottom rail of the sash goes first, then the sill, then the bottom of the jambs where they meet it. The top half of a window is usually fine on a house where the bottom is a disaster.
Push a screwdriver into those spots. Sound timber resists. Rotten timber feels like pushing into a wet weetbix and comes out with fibres on it. Somewhere in between, spongy but holding, usually means the paint failed a few winters ago and the water's only just started, and you've caught it.
While you're there, check whether the window still closes onto its stop all the way round. A sash that's dropped in one corner is a hinge or a joint problem, not a rot problem, and it's a couple of hours' work.
What each option runs
Rough figures around the Illawarra in 2026, per window, supply and install where relevant.
Repairing a sill or a bottom rail is the cheap end. Cut out the rotten section, splice in new hardwood, prime the end grain properly, make good and paint. Call it $400 to $900 a window depending on how much has to come out and whether the glass has to come out with it. Half a dozen in one visit works out cheaper per window than one on its own, because a fair chunk of any job is turning up, setting up and cleaning up.
A new timber window made to match the existing one, fitted into the same opening, is more like $1,500 to $3,500 installed. The frame is joinery, so the cost sits with whoever makes it, and matching a profile on an old house adds to that. Double hung sashes with cords and weights cost more than an awning window. They always have.
Changing the opening size, or going from timber to aluminium, is where it climbs. You're into cladding or brickwork, a new head or a lintel if the opening gets wider, flashing, and reinstating the internal lining and architraves. $2,500 to $6,000 a window is realistic and I've seen worse on a brick place where the sill course had to be rebuilt.
The pattern's the same one I bang on about with kitchen renos. The item you're buying is rarely the expensive bit. What it takes to get the item into an old house that was built by eye is.
The aluminium swap isn't free money
People get told aluminium is maintenance free and timber is a nightmare, and there's some truth in it, but not as much as the bloke selling aluminium suggests.
Aluminium doesn't rot. Correct. Near the water it does corrode, and the cheap end of the market pits and chalks up within a decade in places like Bulli and Austinmer. Timber near the water is fine if it's painted, and it needs painting maybe every seven or eight years on a sheltered wall, more like five on the western side. Neither one is set and forget.
What actually decides it for me is the house. On a 1920s weatherboard or a Federation brick place, timber windows are a big part of why the house looks like itself. Swap them for aluminium sliders and you can feel something's wrong even if you can't say what. The proportions go, the glazing bars go, and the reveals sit at a different depth. It's the same instinct that stops you putting a Colorbond fence across the front of a heritage cottage.
On a 1970s brick veneer with steel-framed windows already? Do whatever you like, nobody's crying.
The bit nobody mentions until it's too late
Two things that catch people out.
First, if the house is in a conservation area, or the window faces a street in one, changing the style can need approval even when the work seems minor. Wollongong, Kiama and Shellharbour all have their own maps of this and it's worth ten minutes on your council's site before you order anything. The NSW Planning Portal is where the exempt-and-complying rules live if you want to read the source rather than a summary.
Second, glass. If you're replacing rather than repairing, whatever goes in has to meet current requirements, which means safety glass in the spots where it's required and, on newer work, glazing that meets the energy provisions. Bigger openings and better glass will change your bill for heating and cooling more than people expect, and the government's own glazing guide on Your Home explains the orientation side of it better than I can on a job site. Short version for around here: the western windows are the ones costing you money in February.
Who should do it
Small repairs, a sash rehung, a sill spliced, a window rebalanced, that's carpentry and handyman work and doesn't need a big production. That's most of what lands on my doors and windows page, and it usually gets bundled in with the other bits and pieces on a home maintenance visit because nobody has just one thing wrong with their house.
Once the job goes over $5,000 all up it needs a licensed builder and a written contract under the NSW building and trade licensing rules. A whole-house window replacement clears that easily. One rotten sill doesn't. If you're not sure which side of the line you're on, or which trade you even need, I've written about carpenter versus handyman elsewhere.
The thing I'd say to anyone staring at a quote to replace the lot: get someone to test them individually before you commit. Windows on the same house age at wildly different rates depending on which way they face and whether the eave covers them. On most old places out here, some are fine, one or two are gone, and the rest are somewhere in the middle waiting on a paint job.
If you've got windows that stick, drip, or have gone soft at the bottom anywhere from Helensburgh to Nowra, ring Dave on 0414 007 351 or send the details through. I'll come and poke at them with a screwdriver and tell you honestly which ones need replacing and which ones just need a bit of work.
Want a hand with this at your place? Get a free quote or call 0414 007 351.
