I'd think that for a pool house, you'd want the floor to 'leach' the water out for ya. You didn't mention what will be in the pool house that would require you to use a mortared grout. You have to figure that unless you live in a frost-free zone, anything you install with a mortar / grout is going to 'crack' under the pressure, even if it's slight.
Consider concrete that's 'colored' like brick and 'stamped' into the shape of brick. There are TONS of options out there. Check out Concrete Products to see EXACTLY what your 'stamped and colored' concrete brick 'slab' would look like. It's a great idea and you know, no one is going to know it's concrete! On this particular WEB page, you can 'poke around' by Product OR Application.
Then check out Solomon Colors for a sample of what the pros are offering out there. This is just a slightly different 'angle' than Symons' angle.
My best to ya and hope this helps.
Jay J -Moderator
PS: If you want to see more options/ideas on this, you can go to My Favorite WEB Search Engine and start 'sifting' through the links that come up. NOTE: Not all of the links that come up have to do with what I'm talking about. Just open each one in a New Window and 'look around' to see if what's 'in there' is written about what I'm referring to. Happy trails!