Here is the scenario. The 2x4 will be running horizontally on the interior of a basement wall below the ground level. It will be attached flat to the wall similar to a ledger board. The wall is made of cinder block (not cement block I assume because the property was built in 1948). The basement was completely gutted down to the exterior walls and all new walls were framed out with 2x4's for a complete remodel of a basement level apartment. All of the exterior walls were framed out with 2x4's with the studs about 1/4-inch away from the wall and secured at the top and bottom with top plates and bottom plates.
However, about 15 feet of one exterior wall has a 4-inch PVC sewer line running along the bottom of the wall about 6 inches above the floor level. So, the wall above that sewer line cannot be attached to a bottom plate along the floor because the sewer line is in the way.
What I want to do is run that wall down to a wood "bottom plate" that is actually attached to the wall instead of to the floor. To do that, I want to attach a horizontal 2x4 flat to the cinder block wall with anchor bolts of some sort. Then nail a second 2x4 on top of that to create the new "bottom plate" for the wall above the sewer line.
Since the 2x4 will be attached to the wall below the outside ground level, I was thinking of using some type of rubber or similar strip to try to isolate the wood from making direct contact with the cinder block to avoid moisture and termite problems. And, maybe I would use pressure treated wood for that one 2x4 -- but I'm not sure about that idea.
So, one question I have is what to use between the wood and the wall -- rubber, tar paper, or what?
And, the second question is how to attach the first horizontal 2x4 to the wall. I know there are different types of anchors that could be used. One possibility would be anchors that go through the cinder block where the hollow part is and anchor from the back. Another possibility would be anchors that just get drilled into the cinder block but make sure that they go in where the block is solid all the way through.
Any suggestions or ideas would be appreciated -- especially regarding what type of anchors to buy and use to secure the 2x4 to the wall.