I'm not an expert but we have had our roof replaced in the last five years. They had to take everything down and lay new plywood over the exsisting skelton.
When you are getting your estimates make sure the cost includes not just the removal BUT THE DISPOSAL of the old shingles.MOST Landfills no longer take shingles without zapping someone a hefty price for them...unless of course you have another use and or means to dispose of them.
Also watch out for uninsured roofers.
Ask for proof of insurance.
I'll let soemone else with more experience answer the techinical part of this. I just remember these two things as being big variables in our roofer selection.

Not a roofer, either, but I do have the care of one large house and six two-story barns, all with 150 year-old slates roofs in a very challenging northern climate.

I see you're in NY, so I trust you haven't actually torn off your roof, yet. Take a breath, this has been an unusually nasty winter, and while you may wind up removing the roof down to the (or including) sheathing, it may not turn out to be necessary.

To begin, please, understand that there are as many Absolute Truths about roof care and maintenance, as there are licensed roofers. (More actually, because there are a lot of unlicensed roofers - and opinionated amateurs, like me- and they/we definitely have their/our own theories, as well!)

Can you find out from the previous owners or from examining the water stains or asking neighbors, is this a new problem, or regular winter carnival-type event? (I'm not trying to make a joke at your expense, but ya gotta keep your sense of humor when dealing with roof leaks. I know that from hard experience.)

If this is an unusual year, then I wouldn't jump into tearing the roof off, if it is otherwise in good shape.

Since you have a modern material (Tamko) your experience may be different from mine. But perhaps it will help you to know that I have no felt, no shield, no drip edge, spotty guttering, no ridge vent or any of the other must-haves you're being offered; some years I have minor problems with ice dams, and most years, I don't.

The reason for this is that ice dams are believed to be caused by factors other than the roof and its attendant components. One of those factors is the vagaries of weather, of course. Another is heat escaping up through the house's walls and creating the ice dam, that blocks the water, that then backs up until it finds a likely crevice and becomes a leak.

Unless your roof also leaks every time it rains heavily in the summer, then repairs or modifications to the roof are all aimed at treating a symptom (water unable to run down off the roof and finding its way where it ought not be) rather the root cause of the ice dams - the build-up of an ice blob in the winter which blocks the water from running down the roof like it does in the summer.
It might be possible to have nearly all the things that are being recommended to you and still have water damage from an ice dam.

First of all, how old is your house? What's your roof like - steep, flattish, hip? How many stories? What style is your house? (Can't imagine how wrapping ice shield or drip edge or other flashing around the fascia boards would look....!) What's the state of your wall and/or attic insulation?

You sound quite worried and fussed. Can't blame you and I'm sorry for it. I expect you'll figure out what needs to be done and it may not be as bad as you fear. A beginning resource would be to contact the Tamko people and/or your builder if the house isn't very old and get their opinions about what to do. They may offer some useful suggestions. You also could do some research here and elsewhere on the web about ice dams.

And bear in mind the suggestions of the other posters about licensing, insurance and dumping permits, etc. There are a lot of opportunities to make the problem worse rather than better; and roofing repairs, even the cheapest estimates, are not inexpensive.

I'm sure others will chime in, and when we have more info, be able to offer some additional suggestions that may be helpful.

If you've had a lot of damage, you might check your homeowner's policy ......

Also, if you have additional heavy snow, is it possible to have the lower portion of the roof raked before the snow has a chance to make a pest of itself? This is a hard job (and can be dangerous), so don't undertake it lightly. Sometimes you can hire roofing companies to come and rake during the winter. Providing they don't damage the roofing, this would be fine.

Am in the middle of a huge roofing problem (CA) with the contractor. Best made plans of men and mice!!!! Check on the internet with your state contractors license board, as a starting place. Make sure their record there is clean. (Mine was, but......) Ask contractor for references of jobs they have done, (this one had done my neighbors house, and all appeared well) I'd ask for as far back as 5-6 years. I would talk to the owners, and go inspect/look at the roofing job. I shutter at the horror tale that I am living right now. I can't say that I did anything wrong in my original decision making, but just got a contractor that in the long haul leaves something to be desired. Am just trying to say, be very careful when chosing a contractor. Good luck.

What is it with roofers? I've found more outright liars and con-men in roofing than in any other trade I've had work on my house. Definitely something to watch out for.

I can't answer your questions, but I can add one more caveat: After you find someone with great skills and reputation, make sure he doesn't subcontract the job to someone else. That's how the Three Junior Stooges ended up working on my barn roof. Grrrr...

Susan

No, not a professional, but I manage a housing rehab program and we always insist on drip edges and never, ever allow roofers to install over the existing roof. Here are my suggestions based on what we do in Western Penn:

1. Rip it down to the sheathing. No roof should be installed over old roofing. You need a clean, integral, dry surface for the longest-lasting roof.

2. Get a drip edge. The drip edge prevents water from dripping into the soffit/fascia and rotting those out, which could be where some of your water was coming from.

3. Housekeeping is right. A poorly insulated attic might be at least partially to blame. When warm, moist air hits the cold roof, condensation and ice dams form. Don't just stuff up the void space w/ insulation, though. You'll need to leave some breathing space. That's another issue, but it's likely that it is causing some of your problem.

4. Get three written estimates on *exactly* the same thing. Keep calling contractors until you find three or four you feel are all telling you about the same thing. Your estimates should be all within 10% to 15% of each other. If I could, I would go w/ the middle estimate. It's likely the most responsible. That is, unless you really like one of the contractors and then go w/ your gut.

5. Regardless, don't do anything w/out that written estimate and draw up a contract that states start date, completion date, etc. and hold some of the payment until the old roof is carted away. Make them responsible for waste hauling and permitting, if required.

6. I wouldn't necessarily bother with your local building professional group. Just because they can join doesn't make them experts. At least that's the way it works here.

7. Housekeeping may again be right. You may not need all of these "extra" things, but then again HK is dealing w/ a slate roof, which is, in fact, a superior (smiley emoticon) roof, and hence ice might not dam up on it as easily. Still, it should not cost you an arm and a leg to get down to that sheathing and to install a drip edge. Can't comment about the shield, but is it really going to cost that much extra? No reason why they can't spec to that level of detail so you can see how much it's really costing you.

Good luck and let us know how it resolves.

I see how many people are stressing insulation and ventilation. We have, as far as I know, sufficient insulation. As for ventilation, we have three very large gable vents. Even if we were to install soffit vents and ridge vents, part of the problem here is the forced air heat and the air handlers and ductwork in the attic and crawl spaces. I an't see how ANY amount of venilation OR insulation is going to being that roof temperature down far enough to prevent ice from forming. We are waiting for two more estimates, but I will insist on shield and drip edges being installed. One of the major stumblling blocks is that some roofers want to take the gutters off and reinstall them ( and they're brand new!) and others don't. Those that do make a big point of stressing "wrapping" over the soffit. Those who do ot want to take the gutters off say the important thing is to get down about an inch past the roof edge (right now the roofing here was started about an inch IN from the edge, leaving, I guess, more of an opening than there should be, and certainly more than a seam)and instaling drip edge.

Leslie, I have the 2003 residential code in front of me. Pennsylvania just adopted it a couple of years ago; not sure if NY has one, but most states do. PA, being the luddite state that we are, was one of the last to adopt.
You could ask your local building code officer if there are minimum requmts for reroofs, shields, etc.

For what it's worth, here's what it says about ice protection for asphalt roofs. Not much else was speced. Might be in there, but I can't find any additional info on gutters.

1. In areas where avge daily temps in Jan is 25F, or less, an ice barrier that consists of at least two layers of underlayment cemented together or a self-adhering polymer modified bitumin sheet, shall be used in lieu of normal underlayment and extend from eave's edge to a point at least 24 inches from the exterior wall of the building.

You know it sounds like the two sets of roofers are talking almost about the same thing. I'd say if your roofer can meet the IRC (or something equivalent) requirementes above, then it wouldn't matter so much if they removed the gutters, if that bothers you. However, a competent roofer should be able to remove the gutters and re-install them without damaging them (spec that they're responsible for damage). When they're tearing off roofing material, they're going to just throw it on the ground and may or may not make it over the gutter, depends on how fussy they are. As in anything, fussiness will cost you up front, but in the long run it's almost always better to amortize that cost over the life of the roof.

BTW, we always require the roofer to throw his material in an approved haul-away container so that essentially none of the material hits the ground. You shouldn't be cleaning up roofing materials and nails, etc. for weeks after the project. I can send you a couple of lines from reroof spec we did, if you want more details.

Probably more info than you wanted.

You need to go to your city and ask to speak to an Inspector at the building dept. they should be able to give you the correct information concerning your roof.

Lots of questions in your original posts. I'll give an opinion on one (well, two)

First, I will say in all of the contractors I have dealt with on my house....roofers have by far been the most difficult to work with, and most willing to overcharge for work that does not need to be done and least willing to explain exactly what they propose to do. Understand every little detail of what they want to do before you start.

It makes no sense to have a ridge vent installed if you do not have soffit vents. What you want to have happen is for cold air to enter low (soffits) and run up the roof and out as hot air at the ridge (via a ridge vent of "pod" vents). This keeps air moving and the roof cool. Gable vents should be fine if you don't have soffit vents and actually may be preferable if there is no way for air to run from the soffits up anyway.

Before you worry about insulation and air flow.....I'd take a look at where hot air may be escaping from your finished house into an unfinished attic or space below the roof (inset lighting, cracks in plaster, attic doors, etc.) Seal those spots.

Best of luck.

"I an't see how ANY amount of venilation OR insulation is going to being that roof temperature down far enough to prevent ice from forming."

you build an insulated enclosure in the attic to contain the HVAC equipment and ducts.

Sometimes it just covers the middle section of the attic, sometimes you move the insulation to the inside of the roof deck and put in short knee walls of insulation.

The insulation on the ceiling under the enclosed area is removed.

Duct board (the 2 inch stuff) or thick foil faced EPS works well.
All the joints are foil tapped and then foamed to create a good seal.

Most of you heat loss into the attic is probably from air escaping from the heated area of the house.