Thanks for the replys. Forgot to add that the firm that wants to do closed cell + fiberglass said it was a code requirement to cover the foam with what he called a code approved ignition barrier. I thought that any foam rated E-84 was OK by itself. Comments? One question I need to ask is why not just spray 4 inches of closed cell and be done it with. That should provide at least R-25. Compared to the inefective R-11 that was in there it would be a big improvement. One reason this may not be practical is it may require two passes as I'm not sure you can apply closed cell at a 4 inch depth in one pass due to excess heat generation and risk of self ignition. Two passes would add to the cost and most likely push it well above the open cell. As for converting the crawl space into a mini basement, I think the jury is still out on that one. If not done correctly I think the consequences are worse than leaving it the way it is now. I also think the cost would be much higher since you still have to insulate the foundation walls and completely seal the volume from the ground.

You need to look at regrading the yard so that water flows away from the house. Also look into gutters and downspouts and make sure they are channeling water away from the house. Then look at doing a perimeter french drain around the exterior footings of the home with a sump pump. Once you get the excess water managed, then it's time to repair what it's damaged. And NO, you do not want to encase rotten wood in foam. Call in a structural engineer to propose the correct fix to your issues and then get some quotes from some contractors to implement it. You also need to get in a landscape contractor to take care of the grading and exterior project.

I just helped my friend who owns a cabin in the mountains which has a basement that one wall is at 50% undergrade and the other exposed wall, cinder block. Since mold comes from dirt 100% vapor barrier is crucially important to slowing down mold spores in the air. Though mold is everywhere exposed ground that does not receive mold killing UV sunlight grows uncontrolled. I would suggest never to put wood on top of the plastic because it will wick moisture considerably and rot. I reccomend slab pavers and float them next to each other. https://www.google.com/search?q=4+x4+ft+cement+pavers&sxsrf=ALeKk02V51mbSbLGF1xq4pOhQ9u3cpq95A:1599487146944&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjqnt35mdfrAhWnlXIEHUgkBq4Q_AUoAnoECA0QBA&biw=1366&bih=657#imgrc=dIckdvbXW2X8QM Better choice pour a 4 inch floor but thats usually too costly. Get www.SensorPush.com ($50) Humidity device with gateway ($100) which will always show you your rooms humidity level. If not conditioning with AC that pushes 50% humidity air to keep air dry you would want fans that evaporate moisture. The biggest concern are critters...mice..chewing electric wires, in furniture...etc. Get www.MouseX.com to drive them away but not kill them so there dying in the walls of your home. I would REALLY stray away from spun insulation above head. Mice nest in this CONSIDERABLY then snakes hunt them as the snakes push and pull your insulation as seen in your pictures. Mice can chew through steel, concrete block and wood easily and any plastic...so the goal is to not give them a easy nesting place. Mice have really made some thouroughfairs in the header joists to previously get into the room. But no mold means no camel crickets or cockroaches which mice eat, no mice means no snakes. So lower humidity so wood beams are under 16% wood moisture content and they wont grow mold and shuts down thebentire food chain. Snakes enter the space from digging under the foundation and coming up right next to the foundation so sealing the plastic to the walls slows the critters down. Sealing the plastic is done best with pin nails shot from a .23 caliber pin nail gun NO MORE than 16 inches apart that keeps the plastic tight enough to keep out snakes. Keep the mice out keeps the snakes out. On top of the 3x3ft or 4x4 ft cement pavers you could put interlocking 3/4 in foam boards and cover with carpet or throw rugs. My friends neighbor works at Trane and got a DEEEAL on central air system system. : )

It's hard to tell from your photo, but it appears that the rim joist (band) of the floor system isn't insulated. That's where the majority of air leakage occurs. If it's not insulated, then your encapsulation contractor didn't do their job right and you'll have colder floors than you should. It also appears that the main trunk lines of your duct system aren't insulated. I suspect the joints are not sealed either. If the crawl is properly insulated, I think you'll find the air leakage from the ducts to be adequate for conditioning the crawl space. That said, sealing ductwork and providing a controlled flowrate of conditioned air to the crawl is preferable. I use an axial fan (the same type used for radon mitigation) to supply air from the living area to the sealed, conditioned crawl space foundations on which we build the majority of our homes.