Last reviewed October 31, 2026.
The estimate is clipped to the refrigerator, and one line carries the whole job: “GAF Timberline HDZ, Charcoal, full tear-off.” A second roofer quotes the same shingle at a different total. A third names a brand you have never heard of. Before you line up the bottom lines, learn what those three letters after Timberline commit the roofer to, and what they leave out.
What GAF puts in a Timberline HDZ bundle
GAF’s Timberline HDZ data sheet (December 2019) and its HDZ homeowner brochure (December 2021) describe a laminated fiberglass asphalt shingle about 13 1/4 by 39 3/8 inches, laid with a 5 5/8 inch exposure. Three bundles make a square, 64 pieces in all. On ratings, the brochure lists a UL 790 Class A fire rating, ASTM D3161 Class F and ASTM D7158 Class H wind testing, and Miami-Dade County product control approval.
Both documents leave out two figures. Neither gives a weight per square. Neither lists an impact class for standard HDZ, so a roofer who quotes a hail rating for it should be able to show where that number came from. Our impact-resistant shingles guide explains how those classes work.
The brochure shows 24 colors, split into national, Harvest Blend and regional shades. GAF asks buyers to look at several full-size shingles before choosing, because printed swatches do not show the blend accurately.
LayerLock and the StrikeZone nailing strip
LayerLock is the feature that turned Timberline HD into HDZ. The 2021 brochure says it “mechanically fuses the common bond between overlapping shingle layers,” and that the added strength let GAF widen the nailing target into a band it calls the StrikeZone, which it describes as the industry’s widest. GAF’s data sheet cites a Home Innovation Research Labs study that compared HD and HDZ on a 16-square deck with a standard four-nail pattern. The roofer placed 999 of 1,000 nails correctly. GAF adds that actual results may vary.
A wider target makes good placement easier. It does not replace a foreman who checks the courses.
The 2019 data sheet also settles mixing old and new. HDZ and Timberline HD can share one roof only when the six-digit codes on the bundle ends match. The whole roof then follows the HD installation instructions. Keep that in mind if a roofer proposes patching an older Timberline roof with HDZ.
WindProven and the four accessories behind it
GAF sells HDZ with a 15-year WindProven limited wind warranty that has no maximum wind speed. Then the footnotes in both GAF documents attach the strings. The roof needs GAF starter strips, GAF roof deck protection, GAF ridge cap shingles, and either GAF leak barrier or GAF attic ventilation. Skip any one of them and the roof falls back to the GAF Shingle and Accessory Limited Warranty.
LI Roofing Co. in North Massapequa sets 130 mph as the lowest shingle wind rating it installs and calls that the HDZ standard (May 2025). The GAF documents we could open print no mph figure for HDZ outside WindProven, and gaf.com refused our requests for the current warranty text. If any accessory on your quote is not GAF, ask the roofer to put in writing which wind coverage applies.
StainGuard Plus and the 25-year algae term
On January 18, 2022, GAF announced time-release algae protection for Timberline HDZ. The release describes capsules infused with copper microsites that let copper out steadily. GAF contrasts them with traditional copper-coated granules that can lose effectiveness. The payoff is a 25-year StainGuard Plus limited warranty against blue-green algae discoloration, available only on shingles sold in packages bearing the StainGuard Plus logo.
The 2019 data sheet, written before that change, listed a 10-year StainGuard term. Older bundles or older paperwork may still show the shorter figure. The brochure adds that GAF ridge caps and starter strips carrying the same logo extend the protection from eave to ridge. Streaks already on an old roof are a separate job, covered on our roof cleaning page.
Lifetime coverage and what raises it
GAF’s brochure defines lifetime as the period the original individual owner of a single-family detached house, or an eligible second owner, owns the property. Install any GAF Lifetime shingle with at least three qualifying GAF accessories and those products earn a lifetime limited warranty, non-prorated for the first 10 years. For stronger coverage, the brochure sends homeowners to a GAF factory-certified contractor and its enhanced GAF warranties. Our asphalt shingle page compares those tiers side by side.
What Long Island roofers charge for Timberline HDZ
LI Roofing Co. names HDZ first among the three shingles it installs most, ahead of CertainTeed Landmark and Owens Corning Duration. Its May 2025 guide prices a complete replacement on a typical 2,000 square foot Long Island house with HDZ or an equivalent at $12,000 to $20,000. That figure covers tear-off, underlayment, ice and water shield, drip edge, ridge vent, flashing, permit, dumpster and its own 10-year workmanship warranty.
County Roofing Systems in Melville, which installs both HDZ and Duration, puts the shingles alone at $3,800 to $4,400 for a roof of roughly 22 to 24 squares. The complete job runs $9,500 to $13,500, depending on complexity and tear-off. The company says the two brands usually price within 5 to 10 percent of each other on Long Island. At retail, Rapid Roofing’s 2026 price roundup lists HDZ at $39.97 a bundle at Home Depot, or about $120 of shingles per square at three bundles, before any labor or accessories.
To see HDZ beside its two main rivals, read our GAF vs Owens Corning vs CertainTeed guide.
Reading a quote that names Timberline HDZ
- The exact product. “Timberline” alone could mean HD, HDZ or another line in the family.
- The accessory list. Starter, deck protection, ridge caps and leak barrier or vents all need to be GAF for WindProven to apply.
- The logo on the wrapper. Ask to see StainGuard Plus on the bundles the day they are delivered.
- The warranty name. Which GAF warranty will be registered, and does the roofer’s certification allow it?
- Any old Timberline staying put. If part of the roof is kept, the bundle codes have to match.
