Once shingles get removed, you can inspect all the plywood sheeting for possible delaminating and or water intrusion problems and adversely affecting new shingle warranty. Many things can contribute to these problems such as failure of the chimney flashings, vents, plumbing stacks, your dish TV, etc.
Ice backup is a symptom of an ongoing issue in your attic. Attics must breathe and be adequately sealed (bypasses only) and insulated. Condensation buildup due to inadequate venting of your attic will cause major significant water and mold damage to all wood surfaces. Our company has serviced many attics over the years, and it seems the two most common problems in our region of the country are insulation in the soffit area blocking the venting needed for your attic and bath and kitchen exhaust fans not attached to the rooftop dumping warm air into the attic. The warm air pushing into your attic during colder weather from the bath and kitchen exhaust fans must be vented outside and not in your attic.
Flashing details are vital as well. When installing shingles or siding. Kick out flashings, pan flashings, drip caps, step tins, etc. all must be installed correctly to prevent water damage from occurring.
As roofing experts, we are happy to provide assistance to deal with these issues and many more. It’s what we do, and we take great pride in our work!