Hi DM, Good news is ita a 150mm dia sewer so you need to stay 1m away from the sewer. You say the sewer is about 10m from a boundary- Use that space for the Private Open Space if design allows. The new Regs say the driveway must be a min. 3m wide and windows facing it need to be treated for privacy. Would love to help you.

I agree- sell the original house and live in the new one. Better Tax benefits. Seek your accountants advice to verify

Tarneit and those nearby areas are experiencing growth but also oversupply of land. Find a house you can subdivide close to transport, schools and shops. After planning approval do the mandatory works to get a title for the lot and flick it. Do one every two years and you could have some real cash in the bank. Or build the dual or triple occ and get two rental incomes instead of one and be cash positive. A townhouse or unit off the plan will take a while to see growth- unless its in the hot areas. The developer has taken his profit out and you have to wait. A recent study by RP Data ( I think) showed unit buyers in Melbourne were worse off as the growth was poor. Buy a home- it will appreciate. And find one you can subdivide and build one or more in the back, If the home is in good condition keep it as banks feel secure and then build behind. Getting approvals take tine and finding a good site which ticks the planning reg boxes is a skill.A good site analyst who delivers a permit is worth getting to know.

You could read a basic subdivision process article on the Property Investing website. Here is a link
https://www.propertyinvesting.com/topic/4999581-subdivision-process-in-melbourne/

So much interest in property development shows the confidence in the market. Key things to watch out for when designing to build are available or developable land if retaining the existing house. We recommend retention is good as not only one retains the asset but its easier to obtain a bank loan with a higher LVR. Site orientation, fall of land, availability and location of services, non restrictive property titles are just a few other things to watch out for. By all means talk to Councils planning officers but if you don’t know the regulations do your research first as Planning Officers are there to answer questions usually.You will save yourself a lot of headaches in the future.Best to do a strong site analysis to avoid future disappointments! Moreover planning officers at most Councils are inundated with Planning Applications as some 14 metro Councils are still in the transition stage when it comes to rezoning. Build costs can range depending on topography, location of essential services and design and finishes. But if its single storey around $1100 sqm is the norm for mid range and if you add an upper floor- however small- the rate shoots up to $1300 K+ Good luck. BTW A 15x15m corner land should yield a good sizded double storey after allowing for open space, parking etc for the existing house.