Header req'd for basement doors

I have a 4" concrete block wall that separates my bathroom and garage. Right through this block wall is a 3" cast iron vent pipe, which is totally embedded in solid concrete. Someone probably chiseled out the block wall to make room for it, then later on pour solid concrete around it. You can see where I painted red is the location of the vent pipe, I painted it so no one would try to drill anchors into it. I needed to "build out" 2-1/2" from this block wall before I hang my cement wall board and tile for my shower area. Originally I had planned to actually build a 2x3 studded wall over the block wall, but the unevenness of the solid concrete patches, as well as the copper pipes running on the surface of the wall makes it tricky. I would have to notch so many places the wall may not be as solid as it needs to be. So I started to change my strategy. I found five horizontal locations across that the wall is quite even and square, and I mounted strips of PT 2x4s across, secured with 1/4" Tapcons. As shown. [IMG]http://i173.photobucket.com/albums/w67/143house/framing/P1010637.jpg[/IMG] [IMG]http://i173.photobucket.com/albums/w67/143house/framing/P1010636.jpg[/IMG] [IMG]http://i173.photobucket.com/albums/w67/143house/framing/P1010639.jpg[/IMG] I then plan to mount 1x3 strips that runs all the way from top to bottom on those 2x4s. The 1x3s will act as furring strips where the cement boards (Durock) will mount onto. Then tiles over the Durock. Will this work? Tile mounted on Durock mounted on vertical 1x3s mounted on horizontal 1x4s mounted on concrete block walls? Sounds like a lot of layers. The 1x3s should they sit on the concrete subfloor, or pushed up against the ceiling to leave some gap below for the shower floor preslope? Thanks in advance.

Hi guys...new to the forum. I am getting ready to build a patio cover in the back yard. I'm a rookie carpenter, but I can swing a hammer and turn a wrench. However, I do not know how to read a framing square. I originally planned on a simple shed type roof under the eaves and it has kind of grown from there. I quickly realized that head room issues would severely limit me if I went under the eaves, not to mention for just a little more money I could do it better. With that said, I now plan to tie into the plate of the exterior wall and put in a 5/12 hip roof. This is going to tie into my existing 5/12 gable. I will use double 2x12's on notched 6x6 posts for the beams. The dimensions will be 16' wide (to outside of beams) and 14' deep (outside of beam to exterior wall) with a 16" overhang. The first thing I need to tackle will be the ridge board and common rafters. Since its not simply a square room I don't know how to figure out the length of my ridge. I plan to use the step-off method on the rafters. The biggest question I have here is how do I determine where to cut my birdsmouth once I make my plumb and seat cuts for the soffit and fascia?