Hi as far as the O.C. basment finished system goes. I feel its very similar to a mobile home interior, they try to sell you on the waterproof and mildew/mold resistance. I have been a property damaged repair contractor in Ohio, Mich and Indiana for more than 20 years. The O.C. System doesnt hold up any better in a heavy moisture/waterdamage/flood situation. I would go with a standard studwall, wood or metal and drywall walls and ceiling. We finish 20 basements per year on average and build more than 30 additions on top of our fire and water work. If you have a serious moisture issue, deal with that first then finish the basement. The price is also high for what your are getting. As far as the rest of your do it your selfers. I have nothing against you save the fact you like to compare your work/quality/knowledge and cost to that of a licensed reputable contractor. Maybe you should try building your own vechicles, filling your own teeth, mending your wounds, butchering your meat and so on. Sure many of you can trip your way through a remodle project with varing results, especially in todays world where there are a million web sites to explain how to do just about anything. Home improvment seems to be the career many of you just can't seem to accept as a legitimate way of making an honest living. The real story is folks in the trades work all day long in the field, go home have dinner with their families then leave to visit homeowners like yourselves, most who wouldnt think of leaving work early to meet prospective contractors during business hours, but dont think a thing of "in the one case above" calling out 15-20 contractors for a free estimate more than likely at nite or on a weekend. Btw our professionaly finished basements start at $35 to $40 per square foot based on the scope of work and yes we dont feel comfortable with a gross profit of less than 30% much less than your mechanic, grocer, doctor, lawyer, or your local gas station. The average age of our employees and contractors is 52. Based on that in twenty years you will get to do all your home improvment projects your self and avoid paying a qualified contractor a well earned wage. Look out for that roof replacment!!! YOUR IGNORANT TO COMPARE YOUR SWEAT EQUITY TO A QUALITY CONTRACTOR If your employer did'nt earn a profit you wouldnt have a JOB

My best luck drying up a perpetually wet basement was a three prong approach. First, we did an interior perimeter drain to sump pump system as it was cheaper for us and basement will never be finished. Second was building a small berm and correcting grade to keep water away from house and putting a drainage route about 20 feet away from the house extending to the front corner of the house. Third was running a dehumidifier When we first plugged in the sump pump, it kicked on every few minutes for weeks. Eventually the rate slowed and then stopped even after a rain after we finished the exterior work. The basement was dry for months when we sold the house but it wasn't long before the problem showed up again. The new owner decided to park on top of the berm and then didn't keep the drainage channel clear so it filled up with sand washed from the parking area. Then he didn't buy a dehumidifier. Within a few months, it was almost like we had never gotten it dry. It was such a shame to see the new owner live with a major water problem when the fix was just a few hours of labor, regular maintenance, and $150 or so.

The purpose of the code requirement for a basement ceiling under I-joists is to extend the time of collapse so it is roughly equivalent to a floor constructed of 2x10's for the safety of fire fighters. In your situation you can choose what you think is appropriate: unprotected, a protective ceiling or a factory intumescent coating depending on the likelihood that fire fighters or you would be fighting a fire in your basement. The protection of living spaces above the garage is more important. Are any of those spaces bedrooms? If you add a ceiling, it should be drywall but you might consider omitting the joint taping so it could be easily removed later. In any case, I would spray the bottom of the floor deck with closed cell foam to protect living spaces above from CO in case a car is left running. IMO future access to plumbing is not so important that you need to expose the pipes and the same goes for ducts. Electrical wiring and data cabling can be snaked later.

"but want to respect our contractor’s final word." How does that reconcile with: "told me there’d been a miscalculation" A 9' basement pour, especially in a basement with occupied rooms, in this era of house building is as important an amenity as having an ice maker. So I'm trying to read between the lines, and not sure if: you are resigned to the mistake; don't know who made the mistake; wasn't too keen on a 8'+ ceiling height to begin with; or don't have the appetite to pursue what was designed. Did the: - construction documents mislabel elevations; - excavator do the math wrong; - concrete contractor skipped over that part - site conditions didn't allow it ________________ Pouring the slab next to the footing, if you can do so, will reduce your interior footprint because of a shelf made by the footing projection. A slab that would want to be supported on piers means the substrate (soil) is not adequate for bearing, so the slab would need to be a 2-way slab (meaning designed to support itself wholly instead of relying on resting on soil). If that was the case, a raft slab would be chosen. Not sure how this relates to your situation.