With the real old fashioned Winter of 2025-2026 ice dams again were afoot and people were reaching to me asking how to avoid. I posted about this previously twice: Win Win Solution for Ice Dams and Icicles and Ice Dams and so looking back at those two posts and this additional sharing hopefully helps.
Recently I was asked about ice dams by a daughter, neighbor, and client. While talking to the client I looked over and saw a graphic illustration of what I have let people know about one half of the solution being a common roof temperature. With unheated barns, the roof is default at a uniform roof temperature and so when snow melts it runs all the way to the ground. Ice dams occur when there is a heated space with insufficient insulation to maintain a constant roof temperature from ridge through eave. Adding insulation while double checking the the roof can take the added weight is the first solution. The other half of the solutions are using waterproofing, commonly WR Grace bituthene also labeled ice dam and water shield under the shingles or developing a bit of metal roofing coming up from the eaves a bit. The metal roofing does set one up for some sliding snow and ice that can damage and hurt and injure so it is important to not have this over doors by providing some gables. Refitting a house with additional insulation is difficult but worth it. Closed cell spray foam or foam board on top of the roof deck and overlay with a wood assembly and then more shingles. Sometimes the wood assembly is complex to allow some venting.
One of the pics shows a barn attached to a house with the barn having no ice dams and the other is a restaurant with standard ice dams.
