Need some tips for roof replacement


#1

I currently have a 50 year old roof on my house which has a cathedral celing. I believe the slope is about 2:12. It is tar and gravel on a few layers of felt. the rafters are 2x8’s 16" o.c. I did a repair to the roof last summer. the chimney and its vents were leaking and so I tore off that section, removed the vents (I upgraded to a H.E. furnace and so chimney was no longer required). Each year I remove several cups of gravel from the troughs, and I think it’s time for replacement. Also, the insulation in the ceiling is only R12, and I want to upgrade. My local utility provides a rebate if I bring it up to their standard which is R28 for a cathedral ceiling. Problem is that my 2x8 rafters won’t have enough space for the added insulation to have sufficient ventilation, so I intend to sister 2x2’s to the existing rafters, replace decking as required, and top it off with a metal roof. I am curious about a couple things. I have had problems with ice damming on the old roof. Can I expect improvement with a raised seam metal roof? Is color a factor with ice damming? I also want to know about what needs to be between the decking and the metal panels? do I need felt, and if so how much? What about flashing? Sorry I was so long winded, but I want to provide as much info as possible so the answers are as useful as possible to me. Thanks gentlemen!


#2

although i know nothing about tar & gravel & very little about steel…i do know you will need ice & water barrier & felt paper. also the ONLY thing that will affect your ice damming is proper ventilation and insulation.


#3

sounds like to me your fixin to screw somethin up, mr mebruce77.
your best bet, with all the prerequsits, may be a spray polyeurothane foam roof system.
Aaronb can probably fill ya in better.
gweedo.


#4

Color has zero effect on ice, water or snow.

If you are really, really concerned about water pens through the roof deck & want a vapor barrier, you could (on top of the roof deck) add a product such as Titanium UDL or TriFlex 30.