SmartJack Foundation Supports
The SmartJacks support the foundation to prevent further sagging. In some cases they can slowly lift the foundation back to it's original height.
Mold
Here's one of the pictures Trey showed the homeowners which shows mold growing on the wood in the crawl space. Wood, an organic material, plus moisture is the perfect breeding ground for mold.
Before
You can see some of the issues with this crawl space. It is dirty and damp, along with mold growing damaging the wood supports. You can also see the falling insulation.
SilverGlo and CleanSpace
Both of these things work together to encapsulate the crawl space. A dry, encapsulated crawl space can significantly lower you heating and cooling bill.