Identifying and fixing leak sources, relevant cracks and water flow on a flat concrete roof?
I mostly agree with Ed Beal. Small or hairline Cracks like C1 &amp; C2 can be simply Caulked for a 10-plus year repair &amp; yes you want to address all of those types of cracks whether they're on the wall or roof, so they don't become bigger cracks. You've got hundreds &amp; ALL cracks are potential leaks.

Break-outs &amp; fully open large splits &amp; spalls like D1 &amp; D3 need to be cleaned of all loose debris &amp; forcibly filled with Hydraulic Cement, it slightly expands within &amp; behind as it cures to make the best water-tightness &amp; backing of the surrounding cement.

Areas like P1 that are in the field of the roof need to be leveled to each side of the low spot's high spots, pitched. Meaning, the P1 outside edge further from H1 will &amp; must be slightly higher than P1's inner closer edge to H2. The entire roof should be shaped like 2 bath tub bottoms with H1 &amp; H2 being the drains.

P2 is quite a bit different since it's blocked by a wall. P2 must be pitched into the roof field with the area at the back of the wall being significantly higher than the area at the front end of the wall. At the front end of the wall P2 then needs to be pitched inward or toward H2.

Your roof must tilt from the front to the back &amp; must also be bellied down from the center &amp; outside walls while always maintaining that front to back pitch in order for H1 &amp; H2 to remove all water &amp; have no puddling. Then, everything can be re-painted &amp; the roof can be sealed.