Polished concrete

Hi everyone. I'm new to the forum and have a query about polished concrete. I'd like to achieve a trowel finish (no visible aggregate). The images I've seen that I like mention an off white slab. Our architect says off white is $350 cbm and normal grey is $200 cbm? Why is it such a big difference? Can you use an additive to achieve a lighter grey surface? Any knowledge would be appreciated..

Hi klm105,

you want to put this in the paving and concrete forum but for a more immediate/detailed reply it might be worth sending a PM to onc_artisan. He is a concreter and has answered q's of mine about polished concrete. However price will be different in different states obviously.

Thanks I hadn't realised there was a concrete forum

polished is not trowel finish

polished is done after the fact and trowel finish is done during install, the finish for house slab would be with a power chopper, the more it is worked the more smooth or 'polished' as some call it gets but it will get to a point and burn ie: the concrete with look like it has been burnt, goes blackish, ultra shiny and looks good

off white cement is more expensive to buy than grey cement. The plant and truck after using off white cement has to be washed out after the conc. is batched

also off white is a 'HE' type cement so it goes off quicker than 'GP' or 'GB' (grey and light grey, gb isnt used in conc. plants by the way) ('HE' = high energy) so there may be a need for a retardent to be added ex. batching plant this also affects cost but only slightly

The local Boral plant here did some white stuff, the off-white cement was bought in 20kg bags and emptied into the trucks one bag at a time.

So the power chopper you mention is a form of polishing or honing? And that is what costs $7k? I can now see why the white is so much more expensive, thanks for that!

form of polishing, dosnt cost more to chopper conc. only he cement and washout cost more.

You can still have polished without agg showing.

Off white cement is only around $1.50 more per bag than normal gp cement.

WHich would be around $30 more.

Still seems expensive at $350 a m3.

I get normal cement at $180m3.

Try a few places some maybe more specialised in the area.

For polished you also need to order 32mpa not sure why but many seem to recommend this.

Good luck

Pulpo

32 mpa because it is more dense than 25mpa.
Burnished concrete with a power trowel.
Honed concrete after concrete has been burnished.

Decorative concrete mixes seem to be a rip off but I had to buy a 20kg bag of white oxide for us to use when we color match out grout and is cost me $60
So the ingredients or coloured concrete with different aggregate halps to bring the price up. I still think they are making a good profit margin on concrete.

ttp://www.policrete.com.au

i paid $22000 for polished concrete and got grey instead of off white. Boral refuses to acknowledge they made a mistake. They say their small print on the brochure lets them out of mismatches. Don't go with Boral.
tDon't

Can you post some photos.
If you could also list the colour of the stones.
I suspect the grouting process had imparted a mix of the colour of stones into the pores of the concrete. But I'll wait to see your answers.

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

$70 sq mtr just for the mix..yeah I'd say that was quite pricey.