This is when there is a heavy rain and water rises in the entire crawl space. This happens infrequently.
A more common occurrence is external water intrusion (water entering the crawl space from outside). An example would be standing water by the foundation of the home. This water will eventually erode the mortar between the brick or even solid block. A water diversion system or french drain is needed, sand is not required to correct this problem. (refer to the water diversion page)
Sand is required when the ground needs to be higher than the water rising in the crawl space. Sand is also needed to fill in low or eroded areas after the moisture intrusion are corrected. We use the below methods:
The end result is sand being installed for the correct reason and serving the proper function.