I am going to build some concrete countertops for my own house. I am completely, 100% confident in my abilities to do what I want done. I did some looking and found a company that produces white cement and white marble sand for the finish coat on Gunnite swimming pools. Both companies claim their cement has additives that bring the psi up to 7,000 pounds in 28 days, both advertise ASTM testing, etc. I know concrete can be tricky stuff. I can buy the pool companies sand and cement (with additives) separately and I'll have $7.70 invested per 70 pounds. The pool company is out of Arizona and has been serving the pool industry (and countertop builders) for many years. I need 20 bags - $160 vs $1,200. Am I missing something here??
(Laminate and Solid Surfacing Forum)
From contributor J:
I am not a guru at all, but I did concrete counters for my own house several years ago. I made my own mix using sand and gravel from a big-box store, and type III Portland cement which I had to get from a specialty building supply. It's the type III, or high early strength Portland cement component that makes it get stronger sooner. I would guess that both Rhodes and the pool people use Type III to bind their other ingredients together. Not that you asked, but one thing I would do differently is that I'd make sure the top edges of the counter were either rounded or had a decent chamfer (3/16" or better). I used square-edged molds with caulk beads in the corners, and ended up with a fairly crisp pencil-edge. Those sharpish edges chipped rather easily during the first year or so.