This old house is suffering from more and more stormwater due to continuous development in the area. The crawl space not only shares a great deal of moisture with the stick frame floor above it, it is taking on sedimentation as the natural flow creeps under the structure through the water table to the stream out back. Additionally, the area is now prone to flash flood due to an overload of impervious cover in the watershed. I believe the best solution is to fill the crawl space with a poured floor. I envision a drain in the floor to quickly evacuate floodwaters, and to support the odd hose down as necessary. I would also like to incorporate PEX tubing to support radiant heat throughout the footprint of the structure(s). I am thinking: undisturbed dirt / vapor barrier / 4" gravel / rigid foam insulation / sand (?) / concrete There's plenty of head room to work with. The existing stick frame flooring/joists are rotten with multiple layers of plywood distributing load and a few rocks supporting failing joists. Or, I could just rebuild joists and floor - but I would like to build for the stormwater that I know is here and for what is coming. Thoughts? Concerns?