Seamlessly blanketing the house (zero-handoff roaming AC wireless)

I've been tasked with blanketing a house in glorious wifi. Layout might look something like this: cable modem in the basement, wired to a router/WAP on the first floor, which is also wired to a WAP upstairs. The sticking point has commonly been getting client devices to relinquish their hold on an inferior connection as they move about the house.

Is there a solution for this? Do both WAPs need to support said solution, or is one good enough? I can't seem to get good information about...

Seamlessly blanketing the house (zero-handoff roaming AC wireless)