How to Install Ridge Cap Shingles
How to Install Ridge Cap Shingles
Ridge cap shingles cover the ridge -- the horizontal peak where two opposing roof slopes meet. This is one of the most weather-exposed areas on any roof. Without properly installed ridge caps, wind-driven rain and snow blow directly into the joint, and water wicks down into the Roof Deck. Ridge capping is the final step in any shingling project and one of the most common repair tasks on aging roofs.
What Ridge Cap Shingles Do
The ridge is where two sloped planes of roofing meet at the top. Field shingles -- the standard shingles covering each slope -- terminate just short of the peak on each side. The ridge cap shingles bridge this gap, overlapping both slopes to create a continuous weather seal. On vented roofs, they also cover the ridge vent, allowing air to flow from the attic while keeping rain and snow out.
Types of Ridge Cap Shingles
Pre-Cut Ridge Cap Shingles
Many shingle manufacturers sell dedicated ridge cap shingles, often matched to their architectural shingle lines. These are thicker, contoured to bend over the ridge, and have a more finished appearance. They typically come in bundles that cover 20 to 33 linear feet of ridge.
Advantages:
- Designed to bend cleanly without cracking
- Thicker profile resists wind uplift
- Color-matched to manufacturer's field shingles
- Faster to install
Cutting Ridge Caps from 3-Tab Shingles
The traditional and budget-friendly method is to cut standard 3-tab shingles into three individual tabs at the cutout lines. Each tab becomes one ridge cap piece, approximately 12 inches by 12 inches.
How to cut:
- Flip the shingle over (back side up)
- Cut along each cutout slot from the top edge to the bottom
- Trim a small angle off the top corners of each tab (this prevents the corners from sticking out when bent over the ridge)
One bundle of 3-tab shingles yields roughly 60 to 65 ridge cap pieces -- enough for about 30 linear feet of ridge. See Asphalt Shingles for shingle type details and How to Calculate Roofing Materials for quantity planning.
Tools and Materials
- Ridge cap shingles (pre-cut or hand-cut from 3-tab shingles)
- Ridge vent (if installing a vented ridge -- see Roof Ventilation)
- Roofing nails (1.25 to 2 inches, depending on ridge vent thickness)
- Hammer or pneumatic nail gun
- Chalk line
- Utility knife
- Roofing sealant or cement (see Roofing Sealants and Adhesives Guide)
- Tape measure
See Roofing Tools Every Homeowner Should Have for a complete tool guide.
Determine Wind Direction
Before you start nailing, identify the prevailing wind direction for your area. This is the direction wind most commonly blows from during storms.
Ridge cap installation always begins at the end opposite the prevailing wind and works toward it. This means the overlap of each piece faces away from the wind, so wind hits the sealed trailing edge rather than catching under the leading edge. Getting this backward is one of the most common ridge cap mistakes and leads to blown-off caps and leaks.
If you are unsure of your local prevailing wind, check weather service data or observe which side of your home gets the most rain-driving weather.
Step-by-Step Installation
Step 1: Install Ridge Vent (if Applicable)
If your roof design includes ridge ventilation, install the ridge vent before the cap shingles. Cut a slot in the decking along the ridge (typically 1 inch on each side of the peak, per vent manufacturer instructions). Center the ridge vent over the slot and nail it down per the manufacturer's specifications. The ridge cap shingles will cover and protect the vent. See Roof Ventilation and Attic Ventilation and Insulation Guide for ventilation design guidance.
Step 2: Snap Reference Lines
Snap a chalk line on each side of the ridge, 5 to 6 inches down from the peak. These lines serve as alignment guides for the lower edge of each ridge cap piece, ensuring a straight, uniform appearance.
Step 3: Start at the Downwind End
Place the first ridge cap piece at the end of the ridge opposite the prevailing wind. Center it over the ridge so it overhangs equally on both slopes. The bottom edge should align with your chalk lines on each side.
Step 4: Nail the First Piece
Drive two nails into the first piece, one on each side of the ridge, placed approximately 1 inch above the exposure line (this means roughly 5 to 6 inches back from the exposed bottom edge). The nails must be positioned where the next overlapping piece will cover them. Exposed nail heads equal leaks.
Step 5: Overlap Successive Pieces
Place the second ridge cap piece over the first, overlapping by 5 to 6 inches. The overlap should completely cover the nail heads from the previous piece. Nail this piece in the same fashion -- two nails, one per side, positioned to be covered by the next piece.
Continue working along the ridge toward the prevailing wind.
Step 6: Work Toward Prevailing Wind
Maintain your overlap and nailing pattern all the way along the ridge. Periodically check alignment against your chalk lines. If the pieces start to drift, correct gradually over several pieces rather than making a sudden jog.
Step 7: Finish the Last Piece
The final ridge cap piece has no subsequent piece to cover its nail heads. This requires special attention:
- Nail the last piece in place
- Apply a generous dab of roofing cement over each nail head
- Press the sealant firmly to create a waterproof cap
- In high-wind areas, apply sealant under the trailing edge of the final piece as well
Step 8: Seal Hips (if Applicable)
Hip ridges -- the angled ridges on a hip roof -- are capped using the same technique. Start at the bottom (eave) end of the hip and work upward toward the peak. Where hip ridges meet the main ridge at the peak, overlap the hip cap pieces under the main ridge cap pieces and seal all intersections generously.
Common Mistakes
- Nailing too high: If nails are placed above the overlap zone, the next piece does not cover them. Exposed nail heads corrode and leak.
- Insufficient overlap: Less than 5 inches of overlap allows wind-driven rain to penetrate. Maintain 5 to 6 inches consistently.
- Wrong direction: Installing toward the downwind end lets prevailing wind lift the overlaps like pages of a book. Always install toward the wind.
- Cracking shingles during bending: In cold weather (below 50 degrees Fahrenheit), shingles become stiff and crack when bent over the ridge. Warm them in a sunny spot or indoors before installing. Pre-cut ridge caps are more flexible than field-cut 3-tabs.
- Skipping sealant on the last piece: The final piece is the most vulnerable because its nail heads are exposed. Seal it thoroughly.
Ridge Cap Lifespan
Ridge caps are more exposed to wind, UV, and thermal cycling than field shingles. They typically show wear 3 to 5 years before the rest of the roof. During your regular Roof Inspection and Maintenance, pay special attention to the ridge line. Cracked, curled, or missing ridge caps should be replaced promptly. See Signs You Need a New Roof and Common Roof Problems for guidance on evaluating overall roof condition.
If only the ridge caps have failed while the field shingles are in good shape, you can replace just the caps without re-roofing the entire surface -- a manageable and affordable repair.
Time and Cost Estimate
Ridging a standard residential roof takes 1 to 3 hours depending on total ridge length and whether you are installing a ridge vent. A small project like a shed roof takes under an hour.
- Pre-cut ridge cap shingles: $30 to $60 per bundle (20 to 33 linear feet)
- 3-tab shingles cut into caps: $20 to $35 per bundle (about 30 linear feet of ridge)
- Professional installation: $3 to $6 per linear foot including materials
