3:12 Roof, what would you do for underlayment?

I am having my roof replaced next week. Per Owens Corning’s (Duration shingles) installation instructions, I can either 1. cover the entire roof in ice and water and install shingles directly over that or 2. do valleys and eaves with ice and water and then a double layer of synthetic underlayment that’s half lapped over every sheet.

All peaks of my house have ridge vents and soffit intakes. I will own the house long term so I’m trying to think forward to the next time the roof needs replacement and they have to replace all decking because of the existing ice and water. Currently have a leak and because of that I’m leaning full ice and water coverage. I live in New England. My roofer said he’ll do whatever method I prefer since that’s what OC says. Thank you in advance.

Ice & water shield with stainless roofing nails for the shingles.

If Malarkey is in your area it is a much better choice for low slope. OC Duration is a good shingle but low slope is it’s weak spot. Malarkey is tapered at the nail line.

Just run 2x 30lb felt if you care bout next replacement, or get grace all over the place :money_mouth_face::money_mouth_face::money_mouth_face:

I agree with previous responses. Either I&W or 2 x 30lb felt. If it was my roof, I would put double thirty pound felt.

If you go the full Ice and water route, get a layer of felt or synthetic on top of it.
The next time you replace it,the shingles will come off clean. If they are applied directly to the Ice and water they will not, they get scraped and it never comes out pretty.