See here to review the Request for Proposal issued by the Mora ISD school district after their voters turned down a new high school referendum in May of 2017.  Look at paragraph three of page three Here.

We are also confident that a transparent and competitive bidding process can yield a plan costing well under the magic “80%” mark. This is the point, where Morris Leatherman marketing research told #518’s school board that a Repair and Renovate cost figure exceeding 80% of the cost to build new, will prompt voters to support new. But the Blume/Turner cost of $35.5 million is only 52% of their Feb. 2018 new price of $68.5 million. And we can do it!