A previous owner built a small cinder block retaining wall, perhaps 50 years ago, between my property and the driveway next door. About 32' feet long, it is now two different heights and is cracked and leaning. I got estimates to tear it down and rebuild a new cinder block wall. It appears that it can be built to be only 3' tall, plus a 12" footing, which is the limit before having to get a permit from the city of Los Angeles. Two contractors ended up bidding against each other, going lower and lower. One is not the person on the license, but I called the license owner and he OKed it. The license owner told me things to look out for in building the wall. For instance, all holes must be filled with cement from top to bottom. He said some contractors make it appear that they've done this when they haven't and the wall is not strong. In the last round of bidding, I asked if all the holes would be filled top to bottom with concrete. The man associated with that contractor said at the current low price he could not afford to do that and neither could the other contractor. He then said that would be as expensive as building a concrete wall, which is a better wall. He gave me a price on a concrete wall--raising the price after I asked how he's going to deal with water runoff so it won't upset the neighbor. I think both men were going to space the cinder blocks at the bottom so the water would weep out, but for the concrete wall he was going to run a pipe to the front of my property and the water would empty onto the sidewalk. He also said that he uses materials superior to those used by most contractors, including 2500 psi concrete, while most use 2000 psi, and US rebar as opposed to Chinese. I would like to know what is really important for building a good wall of this size. Is the difference between cinder block and concrete significant? Are the differences between the concrete and rebar types he mentioned significant? Should 100% of the holes in the cinder block be filled top to bottom, or is there a minimum that is sufficient? What about placement of rebar vertically and horizontally? Should there be sand, gravel or a waterproof material below the dirt next to the wall? If the wall ends up over 3' in any spot, can the city make me tear it down or do anything else? What else do I need to know, and how can I tell if the contractor is doing what he says he's doing, other than paying more for an inspector to watch the process? I would like to go to the store with the person I hire and pay for the materials directly.

I am replacing a porch roof which rotted out due to some sloppy flashing work. The porch roof is attached to the house at a point that is 1/2 stone and 1/2 stucco over block. The flashing job on the stucco piece is okay, but when the stone was repointed a few years ago, the flashing was just attached on top of a ridge of mortar which was applied over the stone (original stone to the house). I believe I need to rip out all of the flashing and replace properly in order to avoid this in the future. For the stucco side, I can chisel out 3-4 inches above the roof line and nail the flashing directly into the block - - But for the stone side, what do I nail the flashing into? I can put a strip of lathe into the stone and apply a thin layer of mortar, and nail flashing into that? And after I'm done, I assume that I nail lathe above the flashing, and then plaster down to the roofline? Sorry if this is a simple question - I'm not a contractor, but my repair budget is shot, so I need to try to do this on my own...Just need to get it right the first time! Thanks in advance - - This board has been a great reference, so looking forward to some suggestions.