I was quoted 700+ per cu for a mix with off white cement...quite pricey.

sounds very cheap.

looks pretty good to me.
dang you got some retaining to do!

I did one about 20 years ago, put all the steel work in as usual for the whole job as if it was going to be a single monolithic pour.
poured…

If engineer has okay,d it all should be well.

I wanna see pics if they do it in 2 pours.
ill be suprised if engineer would even let them.

I wouldnt want it done like that, but it can be done, make sure the engineers know, and that they take adequate steps to waterproof the joint.
Would be better…

This could happen to any type of slab, the cover is far likely to remain more constant on a waffle slab if anything.
I deal with many engineers, each seem to…

Ive seen P sites with 100mm polystyrene sheets laid onto the plastic membrane and then the 300mm waffle pods laid on top of them.
the slab was completely isolated from the…

If I were to have a waffle slab, id insist on 350mm piers at 1800mm spacing, no less than 600mm deep around the entire perimeter of the house.
I've seen…

Builders are at the mercy of engineers, if it was expensive and failed, it wasnt expensive enough, engineers should have "engineered" your foundations to work.

Its true, concrete can look mottled or blotchy as it cures.
Is it coloured through mix? throw on colour?
Photos would help.

@Adam.m
The waffle design looks far more rigid than a raft slab, unless there are key joints how are they designed for movement?

I don't see the logic in excavating into a highly reactive site and encasing large sections of it inside a raft slab.
Both a raft and waffle slab should be resting…

It can happen to any slab that's either incorrectly engineered or installed.
If i had a P class site, id prefer a waffle slab.

Id say the price includes everything else extra that goes along with dropped edge beams.
more work, more excavations, more steel, more concrete, more bricks + 20-30% builders margin....

Cheng does some really cool stuff with concrete.
I went to one of his showrooms in San Fran.
won one of his awards too.... http://www.concreteexchange.com/2011-be ...…

If the garage slab has a 1200 high corefilled retaining wall on it, another 100mm of concrete over the top aint going to be a problem.
Ive done dozens of them.

how deep are the edge beams in the existing slab?
I personally wouldn't be overly worried about the weight, the load is spread out.
Its a simple procedure, no need to complicate…

Just pour over the top, Throw down some filll dust to save on concrete, scrape a few thickened beams in and cover with plastic.
If the existing slab is already piered…

In my experience the higher the mpa, the nicer the crete is to work with. 80 slump 32mpa is always better to work with than 80 slump 20mpa.

Why is 32mpa harder work than 20 or 25?

There are coatings available... ive never seen one thats looks particularly good.

correct

The 82 was standard for the H class slab, the engineer beefed it up because she was having it polished

My sisters house slab was double layer of SL92 @ 100mm thick.
The slab was to be polished, she had the engineer drop the spec to one layer of 82,…

i wouldnt go any smaller than 72 for a driveway, even at 80mm it will be fine

72 with 100mm is fine
ive seen 100mm slabs with F92 as specified by engineers

I dont think you have an issue with slab strength, just the termites. as long as thats sorted, all is well.

looks suss to me, need a better photo.
a piece of waffle pod may have been broken off and floated to the surface, if so, odd that it wasnt fixed on…