Dryer Vent replacement

[Craig C.]

I need to replace an old vinyl/plastic dryer vent venting into attic (2nd floor laundry, built before codes for venting outside).  Looking at using 6' of semi-rigid aluminium from dryer through ceiling, then a 15' run of solid to a new side vent.  Prefer to not put any holes in roof. What about soffit venting?  Anyone have experience with http://www.dryerwallvent.com/wall-vent-intro.html ?

What kind of contractor would do this- roofer, a GC, HVAC?   Obviously, with risk of fire and mold, need this done right and soon.