YES, but for different reasons. While ice dams aren’t your concern, wind-driven rain is. Hurricanes, tropical storms, and severe thunderstorms drive water upward under shingles. Ice & water shield in valleys prevents the #1 leak location in all climates. Around chimneys and walls, it’s backup protection when flashing fails. Even in Phoenix, valleys and penetrations benefit. The cost is minimal during roofing – about $300-500 for critical areas. Skip the eaves but never skip valleys and walls.

Huge difference in performance. Premium brands (Grace, CertainTeed) use thicker rubberized asphalt (40-60 mils vs 20-30), aggressive adhesive that actually bonds to wood, and split-release backing for easier installation. Cheap brands often fail to seal around nails, lose adhesion in heat, and tear during installation. The extra $50-100 per roll prevents callbacks and warranty claims. One leak callback costs more than the upgrade to quality. Contractors installing cheap materials are cutting corners elsewhere too.

Technically possible but never recommended. Proper installation requires direct adhesion to clean, dry wood decking. Installing over shingles creates air gaps preventing proper seal, violates all manufacturer warranties, and building codes require deck application. The only exception: temporary emergency patches until proper repair. If retrofitting, shingles must be removed, shield installed, then new shingles. This costs $5-7/sq ft – why it’s critical to install during initial roofing.

Varies dramatically by location. IRC (International Residential Code) requires ice barrier extending 24″ inside the exterior wall line in areas with history of ice damming. This typically means 1-2 rows at eaves. Many northern states require 36-72″. Valleys don’t have specific requirements but are considered best practice. Low slopes under 4:12 require full coverage. Local codes often exceed IRC – check with building department. Going beyond minimum code is smart: costs little extra during installation but prevents massive damage.

Simple: to lowball bids. Ice & water shield adds $500-1,500 to job cost. Unethical roofers skip it to undercut legitimate bids, betting you won’t climb up to check. Others use one row instead of required two, or skip valleys. Always verify: get installation photos, check material delivery receipts, and inspect before shingle installation. Reputable roofers include it automatically in snow zones and itemize it clearly. If a bid seems too cheap, this is likely what’s missing. The “savings” becomes your problem in 2-3 years.

Generally no, unless you’re in extreme heat zones (Phoenix, Vegas) or have unusual conditions. High-heat costs 2-3x more and is designed for metal roofs that expand/contract. Standard smooth surface rated to 240°F handles any shingle application. The exception: dark-colored roofs in full sun in southern climates might benefit. Cedar shakes and slate need high-heat to prevent moisture trapping. For 95% of asphalt shingle roofs, standard smooth surface is perfect. Don’t let contractors upsell unnecessary upgrades.

Without removing shingles, options are limited but exist: (1) Check attic – you might see it at eaves from inside, (2) Carefully lift shingle tabs at eaves – should see black membrane, (3) Check invoices – material delivery should list type/quantity, (4) Good contractors provide photos during installation, (5) Thermal imaging can sometimes detect installation patterns. If buying a home, hire inspector who checks attics. Missing ice shield is grounds for repair demands. Document everything for insurance – they may require proof after claims.