How do I remove the overlap from merged meshes? I have recently decided to delve back into 3D modeling, I am a hobbyist I guess you could say.  I have been trying to find a solution for this particular problem for days now.  I have scoured this as well as other forums and have yet to find an answer to this dilemma.  This is my first post here so I hope I don't make too much of a fool of myself :P
I am currently trying to merge three rectangular cubes to form a symbol:

The problem arises when I goto render the picture:

I have tried Joining the objects then going back with the Knife and removing doubles, which seems to be the answer to this, but I keep getting the overlap.
I am sure it is a simple fix but I have probably burned myself out on finding it.
Thanks in advance for any help or advice.
If I have managed to miss another answer to this in my search could you please link it.
You could do it with the TinyCAD addon or with some extrudes.

If you want to start with your 3 parallelepipeds you could use the TinyCAD addon:


Download and istall the addon.
Join your parallelepipeds with a ctrlJ, and go in Edit mode.
Select all and press W > TinyCAD > XALL.
Keep everything selected and press W > Remove Doubles.
Delete the inner vertices so that you won't have any inner edges in the final object.
Fill all the faces.




If you want to do it with some extrudes, you could:


Start with a plane, create an edge loop on its middle and tilt it with GG.
Bevel the middle edge loop with ctrlB and create 2 new edge loops.
Extrude the plane.
Select a face and press ctrlaltspacebar to create a new custom Transformation Orientation (named "Face.001" by default).
Keep this new orientation selected.
Select one of the faces you need to extrude, press E and Enter right away.
Move this new face along the Face.001 Y axis.
Same thing for the other face.