Duplex Budget in Sydney

Hi everyone,

I'm looking for some feedback on a Sydney duplex budget I've compiled to make sure the costs are reasonably accurate. I'm new to building and have no construction knowledge or experience, so I've been lurking in forums and doing some research to pull together this budget. I'm hoping to get a good understanding of the potential costs before I start talking to my Bank and engaging an architect.

Some points of note:

• The Sydney block is ~660sqm with a 15m frontage, and Council has a FSR of 0.5:1
• There's a sizable easement (stormwater drain) cutting diagonally through the land. The easement is 10' wide easement and council engineer guesses it would be ~90cm diameter and ~38m long. We would redirect the easement along the side barrier (say 35m) and then frontage (say 15m) to allow us to build the duplex. The council engineer believes we would be able to reduce the width of the easement so it won't have a major impact on the width of the duplex.
This is probably the biggest unknown to us as I have heard anything from 80-120K for this type of job.

• The land is flat but contains alot of trees. Five or six of them are 10-12m+ and I would assume we would need to remove most of them
• Haven't done a soil test/contour survey yet but contract indicated soil type is class 5 acid sulfate which is common in this area and many duplexes have started popping up. There is a bit of rock sticking out the back so it's possible that may add to the site costs
• Aiming for medium-high standard

Any helpful feedback would be greatly appreciated !

Spreadsheet is-
https://drive.google.com/file/d/1vlhLzh ... atOGf/view

Thanks

lawrikeet welcome to the forum
i had a quick look at your google sheets Some figures are way out mate ( some way too high & Low) and without sketches it's hard to check the data , you might also want to check your Percentage calculations as well?
Planning Fee is approx. .35% of $1m= $3.5K not $35K, I also should mention (lol) you aren't paying enough for the engineering $2K Total? (0.2%) this is way too cheap, & you are paying too much for the Architect. $15K (1.5%)
Target 2% X$1 m (total Build Cost)) = $20K Total all inclusive (Design,Engineering & Construction, 3D Model, Quants & Estimates)
BTW Attach/link the Preliminary Sketches (3D Bim Data) using G sheets, ie analytics with dynamic Building & Real Estate Data ie , try simulating/forecasting potential sales profits with at least 3 pricing options in varying markets,,etc
OT,I'll put some examples up on my google community I advise reaching out there if you want python scripts linking BIM Data & metadata.... the Bank Guys love this stuff.)
hth

Thanks for your feedback. I've read that you can typically spend 30K+ prior to construction so if you add architect/engineer/tests/reports/DA fees then that would sound in line with your feedback.


Were there any other line items that were glaringly off the mark?

Would love to look at your sample sketches/analytics so I could start some myself.
At this stage have just been looking at budgetary guidance to make sure the numbers add up before I engage an architect.

Cheers

lawrikeet Your welcome
Try to bring it down from $30K? On my projects it's a fraction of that cost as I do the Design,Engineering,Reports,etc,etc
I Use Python (automation), the internet and Building Information Modelling (BIM) ie Area, Volumes, costs), aim for a high (95%CI) chance of Bank Funding and profitability.

Though your total seems OK at a glance your deviations are way off and problems arise when you overestimate on small ticket items and leave out/ underestimate on big ticket items (ie Stormwater Costs?)

Work on getting the correct Data, analysis & proofs and of course great dynamic presentations help
Tips to start you off
1.Those estimated Costs? need to come from somewhere (council, build up rates/tables,Bunnings pricelist)?..
2.Start with simple flow process Chart and add to the framework ie key data (m2, m3,costs) is used throughout all stages.
Land purchase, Preliminary Development costs, cash flow, Design, Approvals, Services, Engineering, Building, landscaping, Sales price, PROFIT,etc,etc
3 Then break these down .they also need subcategories?
ie.,Category-> subcategory-> items,,, using Pivot Tables help Filters? etc,etc
4. Try to factor/link in Risk (High Med, Low)
5.6.7...
Finally, You will need to constantly check and refine your GSheet application with completed projects..but this can be also be automated
OT Usually if I get enough interest on specific posts I'll put something up ..I am very busy doing my own stuff..but happy to help where I can & when time permits.

Hi there - we are building a duplex in Parramatta with Masterton. We hope to start demo within the next 2 months. Our hydraulics (or what you call external plumbing and drainage) is costing around $70K (including builders margin). It's fairly straightforward work, so I think this is the lower end of the cost range. I have heard of it costing up to $120K. We are choosing for Masterton to manage the work so that it can be done within the contract period. But, this adds the builders margin of around 27% to the cost. Not sure if we'd make the same decision again. We also expect to spend around $20 to $30K to put in a butterfly drain at the front since our driveways are going over an existing drain.

lawrikeet thanks for that budget spreadsheet.

I'm looking to start a similar project in Western Sydney perhaps this time next year at the earliest.
Would anyone have a broad overview of the steps taken and in which order?

1. get full site survey done
2. get architect
3. ?
4. ?
5. tenant vacate property

thanks all!