AC INC Roofing

Roofing Glossary

Plain-English definitions for roof anatomy, materials, performance ratings, storm damage terms, insurance vocabulary, contracting and warranty terms.

Roof Anatomy

The structural and waterproofing parts of a roof system, top to bottom.

  • Decking — the structural plywood or OSB surface beneath roofing materials. Most CO homes use 7/16" or 1/2" OSB.
  • Underlayment — water-resistant layer between decking and shingles. Modern installs use synthetic mechanically-attached underlayment.
  • Ice & water shield — self-adhering bituminous membrane installed at eaves, valleys, and roof penetrations to prevent ice-dam and wind-driven-rain leaks.
  • Starter strip — pre-cut shingle row installed at the eave, providing the first line of wind seal.
  • Field shingle — the main roofing material covering the bulk of the roof.
  • Ridge cap / hip cap — specialized shingle installed at the peak (ridge) and angled corners (hips).
  • Flashing — metal or membrane details that waterproof transitions: chimney, wall, valley, skylight, vent stack.
  • Drip edge — L-shaped metal trim installed at the eaves and rakes to direct water into the gutter and away from the fascia.
  • Step flashing — bent metal pieces interleaved with shingles at wall transitions, replacing continuous "L flashing".
  • Kick-out flashing — diverter at the bottom of a wall-to-roof transition that kicks water into the gutter (instead of into the wall).

Materials & Performance Ratings

Industry standards homeowners encounter on quotes and product literature.

  • UL 2218 Class 4 — impact-resistance rating from Underwriters Laboratories. Class 4 is the highest rating; required by some CO jurisdictions and qualifies for hail-discount endorsements on most major carriers.
  • ASTM D7158 Class H / G / F / D — wind-resistance classifications. Class H = 150 MPH; Class G = 130 MPH; Class F = 110 MPH.
  • Square — roofing unit of measure equal to 100 sq ft. A 2,200 sq ft roof = 22 squares.
  • Pitch / Slope — vertical rise per 12 horizontal inches. "6:12" means 6" rise per 12" run.
  • NFA — Net Free Area, the open area for ventilation airflow. Most manufacturer warranties require a balanced NFA based on attic square footage.
  • TPO — Thermoplastic Polyolefin, a single-ply commercial roofing membrane (Carlisle Sure-Weld, Holcim Elevate UltraPly).
  • EPDM — Ethylene Propylene Diene Monomer, a rubber single-ply commercial roofing membrane.
  • Mod-bit — modified bitumen, a multi-ply low-slope asphalt-based system used on small commercial and low-slope residential.
  • Kynar 500® / PVDF — premium fluoropolymer paint used on metal roof panels with 35–40 year color warranties.
  • IBHS FORTIFIED Roof™ — Insurance Institute for Business and Home Safety hardened-roof standard. Includes Sealed Roof Deck, Enhanced Roof Deck Attachment, and Locked-Down Roof Edges.

Storm & Damage Terms

What you'll hear during a hail or wind inspection.

  • Bruise / impact mark — a dent in the asphalt mat from hail strike, typically with displaced granules around it.
  • Granular displacement — loss of the colored granular surface protecting the shingle mat from UV damage.
  • Mat exposure — black asphalt mat visible because granules have been knocked off; accelerates UV degradation.
  • Soft-metal damage — dents in gutters, downspouts, vents, AC condenser fins, garage doors, window screens. Adjusters use soft-metal damage as collateral evidence of hail size and direction.
  • Wind uplift — wind force lifting shingles off the deck, breaking the seal strip.
  • Creasing — wind-induced bend across the shingle that breaks the integrity of the seal even after it lays back down.
  • Functional vs. cosmetic damage — adjuster term distinguishing damage that compromises the roof's waterproofing (functional, claimable) from damage that's only visible (cosmetic, often disputed).
  • Hit pattern / density — the spatial distribution of hail impacts. High-density hit patterns indicate severe storms.

Insurance Terms

The vocabulary that comes up during a roof insurance claim.

  • FNOL — First Notice of Loss, the initial call to your carrier reporting damage.
  • ACV — Actual Cash Value, the depreciated current value of the damaged roof. Carriers typically pay ACV upfront.
  • RCV — Replacement Cost Value, the full cost to replace the damaged roof with new materials. Most modern policies pay RCV in two steps: ACV upfront, depreciation released after install.
  • Deductible — the homeowner's out-of-pocket portion of the claim. Cannot be waived, rebated, or absorbed by a contractor in Colorado (SB38 / C.R.S. 6-22-105).
  • Depreciation — the difference between RCV and ACV; held back by the carrier until install is complete.
  • Recoverable depreciation — depreciation that's released to you after the install is verified. (Non-recoverable depreciation exists on some policies and isn't paid back.)
  • Supplement — additional scope submitted to the carrier after the initial adjuster scope; addresses missed line items, code upgrades, ice & water shield, steep charge, overhead & profit.
  • O&P — Overhead and Profit, typically 10% + 10% added to scope when 3+ trades are involved.
  • Xactimate — the carrier-standard estimating software. Both adjusters and contractors write scopes in Xactimate format for line-item reconciliation.
  • Matching — replacement of undamaged but visibly mismatched materials so the repaired area matches the rest of the roof. Some states require matching by statute; CO doesn't, but many carriers will pay matching scope when properly documented.
  • AOB — Assignment of Benefits, a document where you sign over your insurance claim rights to a contractor. Almost always bad for homeowners. Don't sign one at the front door.
  • Public adjuster — independent licensed adjuster you can hire (separate from carrier and separate from your contractor) to advocate for your scope. Charges a percentage of recovery.
  • Code upgrade — line items required by current building code but not in the carrier's baseline scope (drip edge per IRC R905.2, ice & water shield in valleys, attic ventilation NFA, Class 4 / 150 MPH where required by jurisdiction).
  • C.R.S. 6-22-101 through 6-22-105 (SB38) — Colorado statute governing residential roofing contracts tied to insurance proceeds. Includes 72-hour cancellation right and prohibition on deductible waiver.
  • C.R.S. 10-3-1115 / 10-3-1116 — Colorado statute prohibiting unreasonable delay or denial of first-party insurance claims.

Contracting & Warranty Terms

What appears on the contract and warranty paperwork.

  • NDL — No Dollar Limit warranty, mainly used on commercial single-ply systems. Manufacturer covers labor and materials with no per-claim cap up to the warranty term.
  • Workmanship warranty — covers installation defects (the way the system was put together).
  • Material warranty — covers manufacturing defects in the products themselves.
  • Limited Lifetime — warranty covering the original homeowner's ownership period (not literally forever).
  • Non-prorated period — initial warranty years where 100% of replacement cost is covered; after this period material warranties prorate down.
  • Pro+ Platinum / Select ShingleMaster / Certified PRO — top-tier manufacturer contractor credentials (Atlas, CertainTeed, Malarkey respectively) that unlock enhanced workmanship + material warranties not available from non-credentialed installers.
  • Mid-roof inspection — municipal building inspection performed at a defined completion percentage (commonly 50%) on the roof, before final shingles go down. Required in Castle Rock, Thornton, Centennial, Boulder, Englewood, Highlands Ranch, and Arapahoe / Jefferson Counties among others.

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