Cost to concrete over driveway

[PotatoTopPie]

Hi Guys

I'm wanting to get our driveway and a carport region (roughly 100 square m) concreted. Currently just has compacted gravel which moves over time and messes everything up which I'm getting sick of.

Anyway - I've got a couple of quotes and they have WILD variation amongst them so I'm not too sure what's going on. I've had as cheap as $80 per square meter to $160 per square meter.

Has anyone had this done recently? What was the per sq M cost?

Not out to pinch pennies here, its important to get a good long lasting job done but at the same time I want to understand what is going on here.

[Don't believe the Hype]

100m2 will require 10m3 concrete roughly $2500+
mesh and chairs - 15 sheets roughly $1000+
prep & place concrete $50 - $80m2

based on these numbers total cost/m2 between $85 and $115/m2

check what's included in the $80/m2 job... it's possible they could do for that and make money if they do big volume as the concrete and mesh prices above are before volume discounts from suppliers...

It's hard to go go wrong with this so don't see the need to go with the high end quote. Make sure the prep has good compaction, the mesh is tied down well and the concrete is 100mm minimum.

[Viking]

Specify minimum 100mm depth and at least 25 MPA concrete. Forget about the steel. Waste of money. Concrete needs cement and plenty of it. You can go to 30MPA concrete. Much stronger.
Chairs only create weak spots and next thing your driveway will be cracking up.

Got a number of driveways and that's all I do. Never cracks up.

[jimO]

It's hard to go go wrong with this so don't see the need to go with the high end quote. .

Hmmmm famous last words

[Don't believe the Hype]

Hmmmm famous last words

i guess it's a relative thing right.

[Don't believe the Hype]

Specify minimum 100mm depth and at least 25 MPA concrete. Forget about the steel. Waste of money. Concrete needs cement and plenty of it. You can go to 30MPA concrete. Much stronger.
Chairs only create weak spots and next thing your driveway will be cracking up.

Got a number of driveways and that's all I do. Never cracks up.

25 or 30mpa... did you build a runway or a driveway?

Even higher strenght concrete has poor tension strength so steel is important as it provides the tension strength. For a few extra bucks you get a far stronger result.

Chairs ensure the steel mesh mesh is at a consistent level in the concrete but you can do without them by lifting the mesh through the poor... less consistent and more likely to have mesh right on the bottom of the concrete or worse bits right on the surface but can do that way if you're really averse to chairs.

[heugumper]

I recently had 100 m sq placed for about $95/m. Some was already boxed by retaining walls and was already gravel base but needed compacting for reasons you described. I went for fibre mesh rather than steel (after much research and reference checking), brushed finish and expansion cuts made. Job well done, good clean up after, will use the guys again.

[Viking]

25 or 30mpa... did you build a runway or a driveway?

Even higher strenght concrete has poor tension strength so steel is important as it provides the tension strength. For a few extra bucks you get a far stronger result.

Chairs ensure the steel mesh mesh is at a consistent level in the concrete but you can do without them by lifting the mesh through the poor... less consistent and more likely to have mesh right on the bottom of the concrete or worse bits right on the surface but can do that way if you're really averse to chairs.

Driveway. Walked hundreds of driveways in the last 20 years and mostly all cracked through using 75mm x 17.5 MPA. It is also used in house floors which is why they all broke in the CHCH earthquake. Try breaking up some of the old Ministry concrete. tough as hell.
Lifting mesh as you go ain't so hard whereas once you use a chair its created a non bonded area in the concrete. Put then in a row and you have a zipper.

Bad practice like so many others in the building Dept.