GAF Timberline Shingles and Roof Systems We Install

Product lines

GAF Timberline HDZ, UHDZ and the lines beyond them

Timberline HDZ is GAF’s core architectural shingle. Its headline feature, LayerLock, fuses the two shingle layers along a wide nailing strip GAF calls StrikeZone, so the installer has a larger target and the nails catch both layers. Timberline UHDZ uses the same construction in a thicker shingle with a second shadow band, which reads as more depth from the curb. The upgrade is mainly about appearance, so it earns its cost on elevations people actually see.

GAF also sells impact-rated and designer shingles. Timberline AS II is the Timberline-style shingle GAF markets as UL 2218 Class 4, and Grand Sequoia is a designer option for homes where the roof dominates the street view. Check both against GAF’s current data sheets before planning around them. Our architectural shingles guide compares Timberline with other brands’ laminated lines.

The GAF accessories that complete a Timberline roof

A roof is more than shingles. GAF sells matching components: starter strips; leak barriers such as WeatherWatch and StormGuard for eaves and valleys; synthetic underlayments such as Deck-Armor and FeltBuster; Seal-A-Ridge or TimberTex ridge caps; and Cobra ventilation. Using qualifying components is what unlocks GAF’s stronger wind and system warranties, so our estimates name each component rather than lumping them together as “accessories.”

Where the leak barrier goes matters as much as whose name is on it. On a Chicago-area roof it belongs along the eaves and in the valleys, where ice dams and concentrated runoff push water back up under the shingles.

How GAF Timberline shingles handle northern Illinois weather

Timberline shingles handle Chicago-area wind well when installed to GAF’s nailing specification, and the algae protection matters on shaded lots under mature trees. Like any standard architectural shingle, HDZ and UHDZ are not Class 4 impact-rated, so in neighborhoods with repeated hail claims we will also price an impact-resistant alternative, from GAF or another brand.

Late-season installs need one extra check. Shingle seal strips need warmth to bond, so a roof finished in a cold snap may stay unsealed until spring unless the crew hand-seals exposed areas. Ice dams are controlled by the leak barrier and attic ventilation underneath, not by the shingle brand; our ice dam guide explains the attic side.

Two GAF quotes for the same shingle: where they differ

When comparing bids that both say “GAF,” check that each one names the exact shingle line and color; lists the starter, leak barrier, underlayment, ridge cap and ventilation products; and states which GAF warranty will be registered and whether that contractor is eligible to register it. Two quotes for the same shingle can differ significantly once you compare the system underneath it. Our roof replacement estimates spell all of this out.

How GAF warranties are structured

GAF’s shingle warranties come in layers. The standard limited warranty covers manufacturing defects and depends on the product and on how the home is used. Above it, GAF offers enhanced system warranties, including System Plus, Silver Pledge and Golden Pledge, that require qualifying GAF system components and an installer GAF has certified for that tier. The top tier adds GAF-backed coverage for installation workmanship. Wind and algae coverage carry their own terms. Terms change, so always read the current warranty at gaf.com before you sign.

ALTA installs GAF products. We do not currently hold a GAF manufacturer credential, so enhanced warranties that require one are not offered on our installations; your estimate names the warranty that applies.

Where GAF fits best

• Homeowners who want a wide color selection in a mainstream architectural shingle
• Projects where a single-manufacturer system of shingles, underlayment, ridge and ventilation is preferred
• Upgrading curb appeal on a visible elevation with the thicker UHDZ profile

Product information last reviewed November 5, 2026. Always confirm current specifications and warranty terms at gaf.com.

GAF questions

Is GAF Timberline HDZ a good shingle for the Chicago area?

Yes. It is a well-regarded mainstream architectural shingle with strong wind performance when installed to spec. Pair it with proper ice barrier and ventilation, and consider an impact-rated shingle if hail is a recurring problem on your street.

What is the difference between Timberline HDZ and UHDZ?

UHDZ is thicker and has a dual shadow line, so it looks more dimensional. Both use the same LayerLock construction; the upgrade is mainly about appearance.

Is GAF Timberline AS II a Class 4 shingle?

GAF markets Timberline AS II as UL 2218 Class 4 impact-resistant. Check the current GAF data sheet before ordering, including which ridge product GAF specifies with it. Our impact-resistant shingles page compares it with other brands’ Class 4 lines, and whether a Class 4 roof earns a premium credit is your insurer’s decision.

Do I need a GAF-certified contractor to get a GAF warranty?

The standard limited warranty applies to GAF shingles regardless of installer. GAF’s enhanced system warranties require a contractor certified by GAF for that warranty tier, so ask any contractor which specific warranty they can register.