I have a log cabin that was built in 1977 in Midlothian VA. It has had the roof replaced once in 1994 and currently has cedar shakes. The roof needs to be replaced, I will use architectural shingles for the new roof. I am having a hard time figuring out what I really need.
There is no attic, the house has cathedral ceilings. Currently the roof is constructed as so:
Tongue and Groove boards (the cathedral ceiling), on top of the boards is
1 inch foam insulation (intended for walls, not roofs), on top of the foam is
felt, on top of the felt is some 1/8 in sheets that hold the cedar shakes. The nails go all the way through to the tongue and groove. There is no osb. There is a ridge vent.
Currently there are leaks when the rain comes in sideways and often throughout the year the walls(pine I think) will condensate, but never to point of dripping.
I understand I can't throw a standard roof on there, but what do I really need?
At the very basic level I think I need tongue and groove boards > foam insulation >OSB > weather sheathing > shingles.
1. Is my understanding correct?
2. Does there need to be venting within too? Should there be spacers between the foam and the OSB? or the foam and the tongue and groove?
3. What kind of R value should I look for?
4. Will this replacement qualify for any tax savings?
5. I received a few quotes where they didn't come in person or ask about the attic, they just used a satellite to get the roof size- I guess this is a standard roof price. The folks who DID look at the roof and understand about the cathedral ceilings had quotes twice to three times what the quotes were for a standard roof. Does this seems reasonable?
I don't want to have to replace this roof any time soon (25 years+) and I'm hoping to see some kind of improvement in energy costs. I will really appreciate any help you all can offer.