Roof experts?

[Irving]

Drip edge on both eaves and rakes is code, almost every where on the front range.

Ice and water shield is what you'll want to ask for on the eaves to resist ice damming, but any good roofer will include that on their estimates and strongly encourage it no matter what. In your city/county, it's probably required above 7,000 feet. You don't need ice and water shield over the entire roof, just in the eaves and valleys should be fine. IWS replaces felt and it is installed 24" in from your exterior wall, so the deeper the soffits and/or the greater the pitch of the roof, the more material is required. Since IWS replaces felt, make sure the estimate doesn't include the full roof square footage worth of felt AND the ice and water shield.

Ridge vents are very common already, and more and more are being installed. They do not have wind driven rain/snow issues that I've seen, and you are correct that you'll want soffit vents as well. Ridge vents also do a great job venting the roof, especially compared to what you have now. You could also consider a powered roof vent, some of them are even solar. A ridge vent is effective and you don't have to worry about it not working.

The other thing that helps prevent ice damming is increasing your attic insulation. Residential roofs are considered "Cold" roof systems, where there is a separation (the attic) between the interior temperature and the roof.

Many insurance companies offer a discount for Class 4 rated roofs, which usually means some sort of impact resistant when dealing with asphalt composition shingles. BEWARE, that right now, a lot of companies are selling Class 4 impact resistant shingles that are NOT meeting that rating in laboratory tests. The test for Class 4 is to drop a 2" steel ball, from 20 feet, twice on the same spot.

All that said, whatever Malarky is selling for class 4 seems to be what people are liking right now. I mean to say that contractors and adjusters are finding the Malarky roofs holding up to hail better than other brands in the same areas after a storm.

Code most likely requires solid decking, and if the house is old enough to have three layers, there is a chance you have spaced decking. Be prepared to pay for new decking, but you won't know for sure until all the other layers are torn off. If one of the layers is wood shake, you're going to pay for decking.

You'll want to fix the soffit/fascia in any areas that were damaged from ice damming when the roof gets replaced, but that will likely require detaching and resetting your gutters. What is the age and condition of your gutters? Were you planning on replacing them as well?

I apologize for any auto corrected spelling, I'm on the phone. Let me know if you have any more questions in the mean time. Also, will you be home today?

What Foxtrot said about vent per square foot is correct.