I assume you mean the contractor rather than the architect. You need to have a contract that states specific work to be completed for a specific cost with no overruns allowed. But then you risk the contractor going cheap on quality to pad their profits. A better approach might be to give the contractor one amount but then pad in a 10% cost overrun for your own budget.

Having just completed a 3 year major renovation of my home, and having overrun my overrun padding through plumbing surprises, floor rot, electrical retiring, failed appliances and contractor deceit, I can tell you that it never ends up costing what you think it will cost.

One caution I would provide is to not focus on increasing the value of your home. The market will make that determination and the amount and cost of work you put in will have little benefit. Until the real estate market picks up, home values will continue to remain depressed no matter how much work you put in to change it.

Fuskie
Who notes a lot of Paid In Full notes on your update and thinks that your remaining and reorganized debt is a positive one building toward the preservation and future enjoyment of a major asset...