Our company is looking to build a 40 rack data center, what are some tips / best practices to employ?

In our region overseas renting rack space AR data centers is very expensive, so building one inside the floor of a nearby building seems to make the most sense.

We anticipate needing 5 racks, but we should have room for 40 total as the space is 2500 Sq feet.

Some things I have in mind are epoxy floors versus raised (recommended by APC in a recent white paper), redundant power, hot and cold zones, a generator on the roof for backup with an ATS and dual redundant air conditioning. Each rack would also have APC? UPS at the bottom.

I've never built data center before so I am looking for all the advice you may have before we start talking to the contractors.