It also helps to paint the pipes flat black. The white PVC pipe reflects the sun light and doesn't heat up like the black would.
I have this problem with one of mine. It has a bend and a horizontal run just a few feet below the roof line, so the copper T is no help. I insulated it in the attic, but if that helped, it wasn't much. I'm pretty sure I tried WD-40 last year with no success. I just cleaned it up last week and put some grease on the inside and top lip, and then coated it with crushed up ice melt, I believe the magnesium chloride. So far, so good, but the real test will be Saturday when it's colder than a witches titty.
https://www.amazon.com/gp/aw/d/B00RENWXVU/ref=mp_s_a_1_1?ie=UTF8&qid=1514654304&sr=8-1&pi=AC_SX236_SY340_QL65&keywords=insul+vent&dpPl=1&dpID=311BhBsEnOL&ref=
This, $27.00 at Wagon Wheel Limber in Washburn. Available to fit different size vents. You won’t hsve a freeze up again.
Wagon Wheel Lumber that is. Called them this morning they have them in stock.
Well I tried to get on my slippery powder covered metal roof and I give it a 50/50 chance I make it on and off the ladder without falling. I'd rather not damage my new roof with ice fishing cleats, what other options a guy have? I have two vents frozen shut.
I got em opened up. taped a plastic measuring cup to the end up a painters extension pole.