Houses in Bent Street, Bentleigh, that will make way for apartments. Number 29 is on the right. Credit:Clay Lucas In the year to June, Melbourne grew by 123,000 and solidly middle-class suburbs like Bentleigh – with a train 26 minutes from Flinders Street, with sought-after public schools, and with great infrastructure – are in the middle of a building frenzy. On Bent Street, trucks carting dirt excavated from new underground garages are everywhere. Townhouses and apartments have mushroomed. For sale and for lease signs litter the street. The urban consolidation going on in Bent Street is being replicated all over Melbourne – a good thing, because the city needs more medium- and high-density housing. For housing affordability, and to slow urban sprawl. My question is: why does so much of it have to be so badly built? Over the past two years The Age's city reporter Aisha Dow has detailed, with depressing regularity, the failings of our builders and building enforcement agencies.

An artist's impression of 31 planned apartments at 27-29 Bent Street, Bentleigh. Many apartment towers are riddled with defects. Some are built with ludicrously shoddy materials or poor workmanship. Others are so badly constructed they may be demolished within years of going up. Since the fire at the Lacrosse apartment tower in Docklands in 2014, it has become obvious that the most basic checks of building materials and building practitioners only get done by enforcement agencies in this state when something goes badly wrong. Melbourne's legacy as a beautiful Victorian-era city is being trashed. Credit:Josh Robenstone There is too much reliance on builders and subcontractors behaving honestly, and when they don't, it falls to consumers to prove they've been wronged. It is a guaranteed way to end up with shoddy results.

The legacy being left for future generations in places such as Bent Street is nothing like so many came there for – the sort of lasting homes that made it a desirable place to live. The Andrews government's new apartment planning rules should help produce fewer terrible places to live. But they will do nothing to improve the buildings we see being slapped up, which will leave so many problems. It's not like politicians don't know this is a major issue in Victoria. I have been at four media conferences over the past decade where one planning minister after another has promised to reform the authority overseeing building in this state. Jeff Kennett badly damaged building regulation in the 1990s, by largely taking it out of the hands of local government and privatising it. Many of the cheap, shoddy buildings we see on Melbourne's streets are a part of his legacy. Institutional recognition of the problem started during Justin Madden's time as planning minister. Matthew Guy came to the planning portfolio promising to rectify what Madden had failed to do. Richard Wynne did precisely the same thing. Little of meaning changed.

The devil in the detail of building regulation is extreme. It is what allows so many hopeless builders to get away with it over and over again, rebirthing their dodgy companies and causing the next unsuspecting customer untold grief. The Victorian Building Authority is meant to be the tough cop on the beat. Forget tough – it's barely on the beat. When developers knocked down the Corkman Irish Pub in Carlton in October, it took the VBA three weeks just to issue a press release acknowledging that it had happened. Is it any wonder a cowboy culture has grown up among demolition crews and developers? One academic I spoke to this week said the sorts of building defects seen in Victoria are still seen in states where the building surveying industry was never privatised. Meaning Kennett-era privatisation is only part of the story. Their view was that the self-regulation that builders once carried out, when big firms employed armies of permanent staff, was no more. The fragmentation of the workforce has made it that much harder to ensure quality: building firms are now tiny and employ a constantly changing group of subcontractors. Queensland has higher regulation of who is allowed on site, meaning only highly qualified tradesmen and women could get on-site to do the work. "You can never police quality completely, but it means less crap gets built," the academic said. Melbourne is growing so rapidly we need more medium-density housing. We also need to feel a lot more comfortable that what's being built are not the slums of the future. Right now, that's exactly what's on the way.

What would William James Fry would make of it all? Clay Lucas is The Age's city editor.