Texas Pier and Beam construction often has a tendency to be "wet - or at least moist" a lot of the time - making it a breeding ground for mold growth. The cost or remediation will depend on the extent of the problem, accessibility factors to the crawl space, and method of remediation. I cannot offer any references, being new to the DFW area. In the future - to avoid this issue: Do your own inspection prior to the rehab/sale.... clean/sanitize/seal the affected surfaces (it's messy, but not difficult). Ensure your crawl space is properly ventilated with foundation vents that aren't plugged/sealed….. and, if necessary - add a fan blower system with humidity controls for on/off function.
Now that you have a buyer - and a inspector involved - it will probably require a proper mold specialist to fix the problem and keep the buyer happy..... rather than a DIY type fix that might have been an option prior to the sale.
IMHO - as a good investor who wants to put out a quality product to maintain your reputation - this type of thing should be on your "to do list" from the onset of a project.
Z
