After getting fairly high radon reading in our home (8.6 piC/L), we had someone come to mitigate the problem. We had already put a stub of 4" PVC through the slab, so it was just a matter of testing for adequent air flow through the gravel underneath the slab/plastic and then running the pipe. The mech room piping was already tight... I'm impressed they were able to squeeze it in. Overall a quality job... we're monitoring the radon level now to see how much the system brought it down. Here is the final installation:
Coming up out of the slab. The u-tube manometer measures the pressure delta induced by an exterior mounted fan.
Piping run in the mech room. The pipe has an upward slope.

Fan and exterior run. Standard aluminum gutter is used to run it up the side of the house.

Final exit is vented over the even of the house. It's nice not to have another hole in the roof.