I have been indirectly involved in some renovation projects, nothing that big, but a few good size ones. Normally they are never finished within the estimated budget. You can have as many inspectors and engineers look that building over and estimate work needed and potential costs. Please notice I said estimated and potential costs. So many time once a project is started more and more problems are found and guess what, with each new problem comes more costs.
When the flipping house craze was going on in our area I did inspections on several renovated homes and found numerous problems. I also met a few nice people that lost their shirts because they put too much into a home and the comps wouldn't support their investment. Example putting 400k into a home where the average comp is 200k.
So you put 20 mil into that old building that is now closed, is the school going to want it when it's finished. What happens if you spend the 20 mil and still need another 5 mil or more?