Hi Matt,

If you are looking at doing a subdivision or Strata titling check you council for section 64 and 94 contributions, with strata title they can amount to $10000 per dwelling/unit for (section 94) – sewer/water, section 64 contributions may be a % of the cost of the project. These are for NSW but not shure about SA, but check you local council because the are paid at construction certificate stage. Just something to think about.

I'm a architectural and structural designer/draftsman in NSW. $5K seems a bit over priced to me, for that sort of extension, I would charge around $2000 to $2500 including engineering drawings (footing and steel beams etc.) and energy rating (BASIX in NSW) but not including surveyor and certification fee's. I have a in house structural engineer, but it depends on how many separate consultants you'll need to see ie. the in house consultants the company has that you select.

Wade Anthony
Architectural and structural designer

Keiko

I'm a structural and architectural designer, and I have a fare bit of knowledge  with tilt panels. I've designed buildings ranging from residential – townhouses/houses, commercial to industrial buildings using tilt slabs. Cost per/M² can vary depending on the thickness of the panels. I've found that using tilt slabs there is a lot more of planning involved up front (but with knowledge this is not a problem) as with all construction there are many different ways that you can approach it. If you are going to build by owner builder (for a house) I would advise to get the slabs tilted by a pro. and do the fix out to save on costs.

In residential and commercial projects, BASIX and BCA section J regulates that insulation is required. Tilt slabs save a lot of time and labor = $, if planned properly you should be able to have a house up to lock up in about 7 – 10 days (not including fix out). I'm working on a project for myself consisting of a 5 townhouse development and costings at the moment is up around the $380K mark finished and including earth works.

Tilt slabs can be cast on site for bigger panels or trucked to site for smaller panels, the biggest panel if used is 8.0m(h) x 9.0m(w) x 175mm(t), it all depends on the crane size available.

Costs (based on costs of my local tradesman)

125 thick slabs allow $120-130 per/M²
150 thick slabs allow $130-140 per/M²

Comparing brick with tilt panels.

There are 50 bricks per/M² + laying (20m² per 1000 bricks approx.) + framing if brick veneer or double if cavity brick (face brick allow 5% waste, commons allow 2.5%)

I hope this helps
If you would like some more information drop me a email
[email protected]

Hi James007
I'm a designer and really it depends on a couple of things –

Buying power of the builder, mass builder or smaller builder who builds to a design, sometimes you can get a mass builder who will build designer homes. (this may be a cheaper option.)

Finishes play a big part, standard or quality finish.

The amount of plumbing/wet areas.

A lot depends on the design, the more trades the more labor costs eg. timber cladding timber  framed – no brickie, timber floor – no concreter, these days tiles seem to be cheaper than colorbond roof sheeting.

As it's a little quiet in the building game it might be worth your while getting plans drawn then get a few builders to quote, maybe make a list of finishes so all the builders quote on the same thing.While in conversation with them see how busy they are (starting dates are a good indication), find a couple who can start with in weeks and see how bad they want the job.
A bit of leg work and you may save thousands $$$

Good quality finishes should be around $9500 – $10000 per square (divide m² by 9.29 = squares)
Mass builders standard finishes around $8500 plus per square