CertainTeed Landmark Shingles Installation: Pro Application Guide
Master the installation of CertainTeed Landmark shingles with our pro guide. Learn nailing patterns, underlayment specs, and starter strip requirements.
Deck Preparation and Underlayment Specs
The structural integrity of a CertainTeed Landmark roof system relies entirely on the substrate. Before unloading shingles, verify the roof deck meets minimum thickness requirements: 3/8-inch for OSB (oriented strand board) or 15/32-inch for CDX plywood, assuming 24-inch on-center rafter spacing. Any delaminated, warped, or water-damaged sheathing must be replaced. Fasten the decking to the trusses using 8d ring-shank nails or structural screws to prevent future nail pops that can telegraph through the shingle surface.
Underlayment and Ice Barrier Integration
For the primary underlayment, use a synthetic product like CertainTeed DiamondDeck or RoofRunner. Synthetic underlayments provide superior tear resistance during the installation phase. Overlap horizontal rows by a minimum of 2 inches and vertical end-laps by 4 inches. In climates where the average January temperature drops below 25°F, the Asphalt Roofing Manufacturers Association (ARMA) and local building codes mandate an ice and water protective membrane (such as WinterGuard) at the eaves. This membrane must extend from the edge of the roof deck to a point at least 24 inches inside the interior exterior wall line.
Starter Strip and Eaves Application
The starter course establishes the baseline for the entire roof and seals the bottom edge of the first shingle course. You have two code-compliant options for the starter strip:
- Dedicated Starter Shingles: Use CertainTeed SwiftStart. These are specifically engineered with a high-tack sealant strip positioned to bond with the first course of Landmark shingles.
- Cut-Down Shingles: Cut the exposed portion (the tabs) off standard Landmark shingles. Install these upside down, with the self-seal strips facing up and positioned at the bottom edge of the eave.
Allow the starter strip to overhang the drip edge by 1/4-inch to 3/4-inch at the eaves, and exactly 1/4-inch at the rake edges. Secure the starter strip with four nails per strip, placed 3 inches from the bottom edge.
Field Application: Chalking and the 5 5/8-inch Exposure Rule
CertainTeed Landmark shingles are designed with a precise 5 5/8-inch exposure. Deviating from this measurement alters the shadow line, compromises the weather-tight seal, and voids the manufacturer warranty. Do not rely on the visual alignment of the shingle cutouts; always snap horizontal chalk lines.
Establishing the Chalk Lines
Measure up from the bottom edge of the starter strip exactly 5 5/8 inches and snap your first chalk line. Continue snapping lines every 5 5/8 inches up the roof plane. For long roof planes, use a laser level or a chalk box with blue chalk (red chalk can permanently stain the granular surface of the shingles).
Staggering the Joints
To achieve the randomized, dimensional aesthetic of the Landmark line, stagger the vertical end-joints of adjacent shingles. The minimum offset is 4 inches, but a 6-inch offset is recommended to prevent water channeling and to create a more natural wood-shake appearance. Never align vertical joints in alternating courses (a 'H' pattern), as this creates a direct path for wind-driven rain.
Nailing Matrix and Fastener Specifications
Improper nailing is the leading cause of wind blow-offs and warranty rejections. Landmark shingles require a minimum of six fasteners per shingle in standard applications. Use only 11- or 12-gauge hot-dipped galvanized or stainless steel roofing nails with a minimum 3/8-inch (preferably 1-inch) diameter head.
| Application Zone | Nails per Shingle | Nail Length | Placement Specification |
|---|---|---|---|
| Standard (Up to 90 mph) | 6 | 1-1/4 inch | 5 5/8" from bottom edge, 1" from ends |
| High Wind (91 - 110 mph) | 6 | 1-1/4 inch | Same as standard, plus sealant at corners |
| Steep Slope (> 21:12 pitch) | 6 | 1-1/4 inch | Hand-seal every shingle with roof cement |
Valley and Ridge Integration
Valleys are the most vulnerable intersection on any roof. CertainTeed recommends the closed-cut valley method for Landmark shingles, as it provides superior water deflection compared to open metal valleys or woven installations.
- Closed-Cut Valley Execution: Run the shingles from the lower-slope roof plane through the valley and up the adjacent plane by at least 12 inches. Snap a chalk line 2 inches from the valley centerline on the upper slope, and cut the overlapping shingles along this line. Apply a 3-inch wide bead of plastic roof cement under the cut edge to seal it against wind uplift.
- Ridge Cap Application: Do not use cut-down field shingles for the ridge. Install CertainTeed Shadow Ridge or Cedar Ridge caps. These are engineered with a wider profile and pre-applied sealant to cover the ridge completely. Offset the ridge cap joints from the underlying field shingle joints by at least 6 inches.
'A properly installed closed-cut valley with ice and water shield underneath will outlast the field shingles themselves. Never skip the membrane in the valley centerline, even in arid climates.'
Cold Weather Protocols and Hand-Sealing
The self-sealing asphalt strips on Landmark shingles require solar radiation and ambient temperatures above 40°F (4°C) to activate and bond. When installing in late fall or early spring, you must implement a hand-sealing protocol to prevent immediate wind blow-offs.
1. Apply three 1-inch diameter dabs of ASTM D4586-compliant plastic roof cement to the underside of the shingle tail.
2. Place the dabs 1 inch from the bottom edge and spaced evenly across the 39-inch shingle length.
3. Do not over-apply; excess cement will blister the shingle surface when summer temperatures rise.
4. Hand-sealing is mandatory for all shingles within 3 feet of the rake edges and the entire ridge course, regardless of ambient temperature.
Troubleshooting Common Installation Defects
Even experienced crews make errors when rushing. Identify and correct these specific failure modes before the final site cleanup.
Symptom: Wavy or Buckling Shingles
Cause: Shingles were installed over damp decking, or the underlayment was left exposed to rain and wrinkled before shingling.
Fix: If caught immediately, remove the affected shingles, allow the deck to dry, replace the wrinkled underlayment, and reinstall. If the asphalt has already set, the entire section must be torn off and replaced.
Symptom: Visible Nail Heads or 'Shadowing'
Cause: Nails were driven into the exposed portion of the shingle rather than the covered nail line, or nails were driven at an angle, piercing the shingle above.
Fix: Lift the overlapping shingle carefully. Back out the offending nail, apply a dab of roof cement to the hole, and drive a new nail in the correct 5 5/8-inch nail line.
Symptom: Sealant Strip Failure
Cause: Dust, sawdust, or debris blew onto the sealant strips during installation, or shingles were stacked too high on the roof, causing the sealant to pre-maturely stick to the packaging.
Fix: Manually lift the unsealed tabs, clean the strip with a dry brush, and apply the three-dab hand-sealing method outlined in the cold weather section.