Help in calculating $$

[Bodgy]

I'm trying to cost a small extension to our house. I do remember that builders work on a $$ per square, but I can't remember.

The extension is simple, single brick, stud/plasterbrd interior. 2 storey, concrete slab, t/g chipboard upstairs.however the lower will be my new shed and I'll line etc myself. Tile roof, 3 windows up, 2 down, no plumbing.

Dimensions 3.5 metres x 5 metres.

Anyone give a rough cost? No time to do it myself and I can't lay bricks (in a straight line that is)

Maybe a Hebel block construct would be cheaper? Exterior will be rendered.

Its just for an addtional bedroom on top and new shed below. All suggestions gratefully accepted.

[craigb]

Try going here and downloading the cost guide:
http://www.archicentre.com.au/html/downloads.html

[Bin J]

Archicentre is a good base - and your extension SOUNDS relevatively simple, but as I discovered, estimate with the Archicentre, then times that by 2!!!!! . Builders seem to add a "Pain in the backside" fee for extensions!

If there are no real problems with "joining" the existing with the new, then go Best Case Scenario = $800/m2, Worst Case Scenario = $1800/m2.

Sorry, no help really!

[Trav]

My estimation technique is to work out how much you can afford and think it is worth, then multiply by 5.

Trav

[floydus]

Estimating would have to be one of the hardest tasks when building anything; just a couple of points, are you owner building? if so the trades will inevitably add more on for dealing with an OB.
I think $1500.00 a m2 is a reasonable estimate. The Hebel will be more expensive, however if you're putting a room on top of your shed, it may be advantageous to use that for the floor, because its a very good insulator.
just a thought.

[Bodgy]

Estimating would have to be one of the hardest tasks when building anything; just a couple of points, are you owner building? if so the trades will inevitably add more on for dealing with an OB.
I think $1500.00 a m2 is a reasonable estimate. The Hebel will be more expensive, however if you're putting a room on top of your shed, it may be advantageous to use that for the floor, because its a very good insulator.
just a thought.

Probably not owner building, unless I finally give the daily grind away
Would Hebel be more costly? I know brickkies hate laying it, but if you use the thick blocks, you only require a single wall. Good point on the insulation tho.

If I did owner build and used Hebel, I'd do the lot myself excepting the sparky. My BIL built a significant extension on his house as an OB, and whilst the Hebel looked pretty wonky bare, when rendered etc, it looked like a bought one.

Thanks all for help, $25 should cover it?