Thanks for that info. I plan on building the garage/workshop this year and I had no clue what even a ballpark would be. Because of my back, I will have tho sub out most of the work. I have found Craigslist a great place to find skilled workers for reasonable prices. With the economy in the shitter there are many unemployed construction workers willing to work for a fraction of what their services would cost in a booming economy. I recently regrouted my two bathrooms. It took me forever because of my back, but I considered hiring someone too do it. I put an add on Craigslist and within a day I had 40 responses, most with references willing to do the job for an unbelievable low price. Since I can be there to monitor the work I might go this route. I have7k budgeted for the job and figure I can build a very nice 24x24 for well under that.
Are you wanting your concrete to be impervious? IOW, is it the final surface (presumably polished) or is there anything going on top of it?
The reason I ask is that we had polished concrete floors done for our kitchen/lounge room area. We can only conclude they used the wrong concrete mix as the stuff is like a sponge, and we have to leap and wipe up every spill before it stains: our goal was that we could wipe up spilt food, wine etc without a care.
The original contractor put in 2 or 3 coats of sealant, which disappeared like it wasn’t there. After a couple of years we had a new guy come in who took off the top few mm with a grinder, and put on a new coat of a sealant that he guaranteed would do the trick. After a further 7 coats of the same stuff he gave up, the 8th coat sucked into the slab just as fast as the first one did and made no difference whatsoever to its permeability. We’d basically have to have the entire slab jackhammered up and redone, which given it’s floating 3 metres in the air in the middle of the house is simply not going to happen.
The moral is: get someone who knows what they’re doing, not the cheapest contractor.