your location sounds idyllic but make sure you check all the bushfire setbacks as it's tragic to have to remove trees if there's a safer locationa but you'll eventually need an earthmoving team to prepare your house site so my advice is to not wait till you're ready to build start now with a good all weather driveway and clear the house site with big water tanks and if possible allowing enough room for a generous parking area big enough for several tradies' utes and room for cement trucks etc to turn around..many people seem to leave all this effort till after the house is built but the extra convenience of a reliable driveway before, during and after building is well worth the effort and for an extra steep site i'd consult an engineer to design the best location as nothing worse after you move into your new rural home than to be housebound by a flood or erosion and/or nobody can come to visit..and for a steep site that's unsafe for a 4wd i think you need professional help...btw also consider a big dam/s at the same time as it will help with your BASIX certification and also looks great and costs can be discounted by not having to transport all the big machinery several times

A few points.

1. Although the top of a hill seems like the ideal location you will be buffeted by winds on the peak. Better to site the house about 100m below the crown of the hill. You will still get the views but importantly be sheltered from weather while still being situated out of the cold valley. While wind may not sound too bad, you'll be surprised how much more difficult this will make gardening especially in the environs around yass. The earth there isn't very water absorbent so all your watering is going to run off leaving your garden dry and then the wind will be extra dehydrating and harsh. But siting on the slope, yes you will need to terrace but you wiill also benefit from runoff further up the hill.

2. With a drive that steep you are going to need asphalt. Compacted road base and gravel will just wash away in the first heavy rain. A dirt road will also be suspectible to erosion and minor land slips leaving deep fissures in the shoulder.

3. You are going to need proper runoff mitigration as soon as you cut a path up the hillside you are simultaneously creating a way for water to gain velocity and force from runoff. I would consider gabion reinforcement on the embankments or at the very least plants of either lomandra or vetiver (deep rooted grasses) to slow water down as it traverses the hill side. These grasses will also capture leaves and other debris preventing it from becoming dangerous in a storm.

To be honest it will be worth you engaging an engineer to design your drive including run-off management and whatever other reinforcements you may require. If you wait until you have a major storm and your drive becomes unpassable it will be far more inconvenient.

First chat with Council. They may have siting controls particularly in relation to ridge lines. Talk to a couple of local contractors regarding the road. Try some neighbours for advice on who to use.

Lots of good points made by Austere Hamlet.

However with such a long driveway it is going to be a lot of money. The cheapest option would be to buy a 4WD drive vehicle that has good ground clearance and can manage the slope in all types of conditions. Either use it as your daily drive, or just as your unregistered driveway transport, and park your daily drive (the nice car) at a designated changeover point towards the bottom of your driveway.

Sounds like an exciting and expensive project.

Best of luck with your budget,

Dr Retro of Dr Retro House Calls/Dr Retre Virtual Visits.

problem with your idea Dr Retro is that it makes building very difficult, you can't accept any deliveries to the house or have guests arrive in their own cars and it makes it dangerous to escape in fire weather..we invested in better driveways and its made life so much easier

Thank you for the thoughtful replies!

The top of the site has a number of relatively flat (and large) building pads - just kinda lucked out with that. There is a site a little lower that is like a dress circle that is below the peak, which would be out of the wind. And it is not a bushy block, particularly at the back where the house/sheds would go, so bushfires aren't as big a concern as they might be on other blocks. It is rocky, like a lot of the Yass valley, though.

Really, for us, it is a matter of "how does a cement truck", "a truck with modular building components", etc etc, get up the current track. As I say, a 4wd, or Awd vehicle can do it - and if somehow we could magically have everything built there, we could manage the track kind of as Dr Retro suggests. It's just that that isn't an option for building I feel.

I think seeking some advice from a local engineer is going to be the next step.

and you need to keep in mind that after the building is finished you will still need to have a big truck for furniture delivery and landscaping supplies now and into the future and nice to have space for a crowd of friends and family to come and go safely...my vote would be to build on the dress circle site for more comfortable everyday living and add a lookout at the top of the hill as a destination for regular walks

Yes, I would tend to agree, oklouise!

A KM of asphalt roadway may just have to be factored in to the cost of building!

Are you sure it’s an average 40-50% grade. 25% is as steep as you would want to go.