2 i have tested several types of bags.
Pouring concrete under existing wall.
Deck footings closer than 5 to an existing exterior house wall.
Pour the concrete in small sections spreading the concrete by moving the chute back and forth and by having the driver pull forward as you go.
In this video we take you through the basics of how to remove set up and pour a concrete room with in your own home.
I would also pour concrete higher than the existing deck in order for you to slope the top of the pour i m order to shed water.
Footings under existing slab.
Pour an interior wall.
4 i can disprove your theory that the concrete will not set up correct due to water ratios.
3 that video above with the guy putting steel in the bags is my video.
And if a wall is chipping or crumbling it s fair to say the bag was taken off way to early.
A professional foundation crew will construct a one sided concrete form inside the old basement perimeter and pour a new concrete wall.
If you re not overly concerned about seams in your slab you can notch out sections of your floor under your walls and pour footing sections to support the wall partially then remove the rest of the wood floor and pour the rest of your slab use re bar extended past through the forms of your first footing sections so they can be tied into the main slab.
This may require jacking up the car port to accommodate.