if you have a 4/12 front porch that dies back into a 12/12 main roof (and you live in a winter climate), would you run ice shield all the way up the porch and main to get your 24" into living space? Or just from the point on the porch roof where living space starts? I know code doesn’t require ice shield over non-living space around here, but this is kind of an ambiguous spot that I run into often. Seems like overkill to run it all the way up.
that is a great question, we go all the way just to be sure we meet code. i think in michigan it would depend on which inspector you were dealing with if any.
any 4/12 pitch should be full I&W shield anyway.
I encourage clients to do full Ice and Water shield in heavy snow climates. On what you are describing I would run up 4/12 and 6 feet up 12/12. Ice damns tend to start at the bottom of roofs over unconditiond space and work up to heat from home. I also Ice and water any pitch 4/12 and under due to our climate
ok suppose porch is a 6-12 pitch what then
Code is 24 inside heated wall here in michigan but ice and water the whole roof??
Gutter edge, 3’ above and below pitch change. Don’t want to create the vapor barrier
we cover the porch and go at least 4 1/2’ past the eave. no we do not ever ice shield the whole roof. some cut up roofs seem to take half i+w and half felt though. generally if it isnt 3 layers, steep and cut up we dont get it.
Like gtp1003, code in our neck of the woods is 24" past the heated inside wall plane.
But Vancouver isn’t a crazy hotbed of snow and ice (pardon the pun).