Ice and water shield is peel-and-stick protection. Unlike regular underlayment, which is fastened down and simply sheds water, this rubberized asphalt membrane bonds directly to the roof deck and self-seals around every nail driven through it. Roofers run it where water concentrates or backs up: valleys, eaves, around penetrations, and on low-slope sections where drainage is lazy.
Do Oregon roofs really need "ice" protection?
Around Roseburg and Riddle we don't see many ice dams — but the membrane earns its keep anyway. Douglas County's real threats are wind-driven rain that pushes water uphill under shingle edges, and fir needles damming valleys so water ponds and creeps sideways. In both cases, water gets past the shingles, and a sealed membrane underneath is what keeps it out of the house. Homes up the North Umpqua toward Glide, at higher elevation, do pick up real snow — there the classic ice-dam protection matters too.
When it's missing, what it costs you
A valley with nothing but old felt under it will eventually leak — usually mid-January, usually over a living room. Valley and eave leaks soak insulation and drywall before anyone notices. Membrane in the right places costs relatively little during a roof replacement and is exactly the kind of spec worth asking about when you compare bids. More in our winter roofing guide.
Where should ice and water shield go on a Douglas County roof?
At minimum: every valley and around every penetration. We also recommend it along eaves and on any transition where a steep plane dumps onto a shallower one — the spots where our rain volume tests a roof hardest.
Related terms
Underlayment · Valley · Eave · Low-slope roof