The house must have ridge vents inplace that's why they are not vented
already.I wouldn't go to all that trouble.
You can do it if you want but I'm just to lazy ,and don't know if you
will gain anything .They do sell vented ones at the borg.
Jr.
http://community.webtv.net/awoodbutc...oodWorkingPage
http://community.webtv.net/awoodbutcher/CARWRECK