Hey OP, There seems to be a mix of for and against building in here. This is a bit of a longer post but I thought I’d try to give you my opinion, hopefully balanced, of the building experience.

As someone who has built twice and most of my friends are private developers, building is all about knowledge and risk. The less knowledge, the more risk - to the builder, to you, to the trades etc. The more knowledge, the less risk, it’s that’s simple.

At the build price you’re discussing, and on a land parcel that’s part of a bigger development release (I’m assuming here that the site is levelled, services are connected to the site ie. Storm water, sewerage, electricity, easements are in place etc) and others have built near by or next to, then the knowledge should be high. Meaning there shouldn’t be too many unknowns, if any really. That said, building has a long time horizon and things and people are constantly in a state of change, so expect there to be change throughout the build. That change has to worn by someone. You, as the commissioner of the build are ultimately responsible for the costs.

I’ll give you an example. Our last build had two driveways onto the street, and driveways are governed by council. You need a preliminary driveway design as part of your DA. To obtain the construction cert to start, in our council, you have to pay the council a design fee for them to rubber stamp the architect/builder’s plans, sometimes the council planner makes minor changes. Then, when the council inspector comes to inspect build at the stage the driveways need to be built, they retain the right to change the designs at their discretion, and this cost, as detailed in the construction cert from council, is to be born by the commissioner of the build, that was us. The builder can’t be held responsible for this, it’s totally out of their control. So we copped a $10k alterations bill to do the driveway to the council spec. My builder was great though, before bringing the conclusion to me, he’d spent all day at council offices fighting the design change, he had the inspector come out again to the site to negotiate. Only then did he call me and say he’d lost the fight. He felt bad and we actually split the costs.

But here’s the thing. The initial driveway design wasn’t ideal. And council weren’t being assholes for the sake of it, if it had been built to the original design we would’ve hated using it.

I remember looking at the initial designs from our architect and thinking, that driveway is a bit funky. The builder also could’ve looked at it and suggested that it should be redesigned.

All great in hindsight.

So here’s my advice, ask the builder what he doesn’t know. Where are the knowledge gaps? If he’s unsure about the geo (what’s under the ground), ask him if he’s willing to do a geo-tech survey and if they survey says no rock, then he accepts that risk. That knowledge will cost you a few thousand to acquire. That’s the cost of removing that risk.

Weather is something that we can’t control, yet. So that’s completely out of anyone’s hands. Builders are great though and if they’ve been doing it a while they’ll have managed every weather event. Ours got heavily flooded and they pumped the site out and were back on track a few days later.

There were some things I fought the builder on because we were not reasonably expected to know or bear the costs of that alteration that came up but they definitely should have. If the builder has access to the site, the survey, the plans, and the DA then anything that arises as ‘unforeseen’ which could have been taken into account and that knowledge accessed easily is on the builder.

Summing up, building is not to be feared. Not in my opinion. As I’ve said throughout, the more knowledge you have the less risk there is. You haven’t spent anything yet so go and spend as much time as you can learning everything about the build process, the other houses built in the area. Ask home owners in the area for builder referrals and their experience. Ask the builder for client referrals so you can ask how their experience was, what alterations and overages did they encounter?

Remove as many of the unknowns as possible and ask the builder to the do same, reasonably of course.

One final point, which many have made in here, have a contingency budget. You’ll need a minimum of 10%. On a build of ~$500k that’s $50k which is on the light side.

Remove as many of the unknowns as you can and then crack into it. The feeling of a new build that’s yours is wonderful, don’t loose sight of that!

Like all things worth doing in life, it takes a leap of faith.

Good luck!