Roofing Glossary
Your complete guide to roofing terminology and definitions from the experts at Fairfield Peak Roofing.
A
Asphalt Shingles
The most common residential roofing material, made from a fiberglass or organic mat coated with asphalt and mineral granules. Available in architectural and three-tab styles, they offer excellent durability and weather resistance at an affordable price point.
B
Built-Up Roofing (BUR)
A flat or low-slope roofing system consisting of multiple layers of tar and waterproof materials. Commonly used in commercial roofing applications, BUR systems are durable and cost-effective for large, flat roof areas.
C
Cricket
A peaked saddle structure built behind a chimney or other roof penetration to divert water away and prevent pooling. Crickets are essential for preventing water damage and extending roof lifespan in areas prone to debris accumulation.
Cupola
A small, dome-like structure on top of a roof, often used for ventilation or decoration. Cupolas add architectural interest while improving air circulation in attics and upper spaces.
D
Deck
The structural surface of the roof, typically made of plywood or OSB (oriented strand board), onto which all other roofing materials are applied. A solid, properly installed deck is critical for roof performance and longevity.
Drip Edge
Metal flashing installed along the edges of a roof to direct water away from the fascia and prevent water damage. Drip edge is required by building code in many areas and protects vulnerable roof edges from rot and deterioration.
E
Eave
The lower edge of a roof that overhangs the exterior wall. Eaves provide shade, direct water away from the building foundation, and protect exterior walls from weather damage.
EPDM (Ethylene Propylene Diene Monomer)
A synthetic rubber membrane used in flat or low-slope commercial roofing systems. EPDM is durable, weather-resistant, and cost-effective, making it a popular choice for commercial buildings.
F
Fascia
A vertical board mounted to the ends of roof rafters, to which gutters are typically attached. Fascia protects the roof edge and provides a finished appearance to the roofline. Learn more about our soffit and fascia services.
Flashing
Thin pieces of metal or other waterproof material installed around roof penetrations, valleys, and edges to prevent water infiltration. Proper flashing installation is critical for preventing leaks and is a key component of quality roof repair work.
G
Gable
The triangular portion of a wall between the edges of intersecting roof pitches. Gable roofs are one of the most common residential roof styles in Lancaster and throughout Ohio.
Granules
Small ceramic-coated mineral particles embedded on the surface of asphalt shingles. Granules protect the asphalt from UV damage, provide color, and improve fire resistance. Excessive granule loss indicates aging shingles that may need replacement.
I
Ice Dam
A ridge of ice that forms at the edge of a roof and prevents melting snow from draining properly. Ice dams can cause significant water damage and are common in cold climates like Ohio. Proper insulation and ventilation help prevent ice dam formation.
Impact Resistance
The ability of roofing materials to withstand hail and other impacts without damage. Impact-resistant shingles may qualify for insurance discounts and are recommended in areas prone to storm damage.
M
Metal Roofing
Roofing panels or shingles made from metal materials such as steel, aluminum, or copper. Metal roofs offer exceptional durability, longevity (50+ years), energy efficiency, and weather resistance.
Modified Bitumen
A hybrid roofing membrane combining asphalt with modifiers and reinforcements for improved performance. Commonly used on low-slope commercial roofs, modified bitumen systems offer excellent waterproofing and weather resistance.
P
Pitch
The steepness or slope of a roof, typically expressed as a ratio of vertical rise to horizontal run (e.g., 6:12 means 6 inches of rise for every 12 inches of horizontal distance). Pitch affects water drainage, material selection, and installation complexity.
Penetration
Any object that passes through the roof surface, such as chimneys, vents, skylights, or pipes. Penetrations require proper flashing and sealing to prevent water infiltration.
R
Ridge
The highest point of a roof where two sloping roof planes meet. The ridge requires special cap shingles or ridge vents to provide weather protection and proper ventilation.
Ridge Vent
A ventilation system installed along the ridge of a roof to allow hot, humid air to escape from the attic. Ridge vents are essential for proper attic ventilation, preventing moisture buildup and extending roof life.
R-Panel
A type of corrugated metal roofing panel with exposed fasteners. R-panel is cost-effective and commonly used on agricultural buildings, barns, and commercial structures.
R-Value
A measure of a material's thermal resistance to heat flow. In roofing and attic insulation, higher R-values mean better energy efficiency. The U.S. Department of Energy recommends R-49 to R-60 attic insulation for Ohio's Climate Zone 5. Insufficient R-value contributes to ice dam formation in winter and elevated cooling costs in summer. Proper insulation is a key factor in overall roof ventilation performance.
S
Sheathing
The boards or sheet material (typically plywood or OSB) fastened to roof rafters to form the roof deck. Sheathing provides structural support and a nailing surface for roofing materials.
Slate Roofing
Premium natural stone roofing material known for exceptional durability and beauty. Slate roofs can last 100+ years and are often found on historic buildings throughout Lancaster's downtown.
Soffit
The exposed surface beneath the overhanging section of a roof eave. Soffits often contain ventilation openings to allow air circulation in the attic. We offer professional soffit and fascia installation.
Standing Seam
A premium metal roofing system featuring concealed fasteners and vertical legs with seams that stand above the roof surface. Standing seam metal roofing offers superior weather protection and modern aesthetics.
Storm Damage
Roof damage caused by severe weather events including wind, hail, fallen trees, and heavy snow. Ohio's severe weather makes storm damage repair one of the most common roofing services in Lancaster.
T
TPO (Thermoplastic Polyolefin)
A single-ply roofing membrane used on flat or low-slope commercial roofs. TPO is energy-efficient, heat-reflective, and resistant to UV damage, mold, and punctures.
Truss
A prefabricated structural framework designed to support the roof deck and loads. Trusses are engineered for specific span and load requirements and are the most common roof framing method in modern construction.
U
Underlayment
A water-resistant or waterproof barrier material installed directly on the roof deck before shingles or other roofing materials. Underlayment provides critical secondary protection against water infiltration. High-quality underlayment is essential for long-lasting roof performance.
V
Valley
The internal angle formed where two roof slopes meet. Valleys channel large volumes of water and require proper flashing and waterproofing to prevent leaks. Valley flashing is one of the most critical components of roof installation.
Ventilation
The process of providing air circulation in the attic space to regulate temperature and moisture levels. Proper ventilation prevents ice dams, reduces energy costs, and extends roof lifespan. A balanced ventilation system includes both intake vents (soffit) and exhaust vents (ridge).
H
Hip Roof
A roof style where all four sides slope downward to the walls, meeting at a ridge in the center. Hip roofs offer excellent stability in high-wind conditions and are common in Fairfield County due to Ohio's severe weather. They require more complex flashing and repair work at the hips than gable roofs.
Hip-and-Valley Roofing
A complex roof design combining hip sections and valley intersections. These roofs require precision cutting and more extensive flashing at every transition point. Proper installation is critical to prevent leak pathways where sections join.
J
J-Channel
A J-shaped metal or vinyl trim piece used to finish the edges of siding or soffit panels. J-channels provide a clean termination point where panels meet walls, windows, and trim boards. Proper J-channel installation is essential for preventing water intrusion in siding projects.
L
Leak Barrier (Ice & Water Shield)
A self-adhering waterproof membrane installed under shingles in vulnerable areas — eaves, valleys, and around skylights. In Ohio, building code (IRC Section R905.2) requires leak barrier protection at eaves in regions subject to ice dam damage. It creates a secondary waterproof seal even if shingles are lifted or damaged.
Low-Slope Roofing
Roof systems designed for pitches under 3:12 (less than a 14° angle). Low-slope roofs require different waterproofing systems than steep-slope roofs, typically using membranes like EPDM, TPO, or modified bitumen. Common on commercial buildings and some residential additions in Lancaster.
N
NRCA (National Roofing Contractors Association)
The leading trade association for the roofing industry, providing safety standards, installation guidelines, and contractor certification programs. NRCA membership indicates a contractor's commitment to professional standards and continuing education — an important factor when evaluating local roofing contractors.
Nail Pattern (Fastening Schedule)
The specific placement, depth, and spacing of nails required by shingle manufacturers to maintain warranty validity. Improper nailing — too high, too low, or overdriven — is one of the most common installation defects and can void manufacturer warranties while reducing wind resistance rating.
O
OSB (Oriented Strand Board)
An engineered wood panel made from compressed wood strands used as roof decking. OSB is the most common roof deck material in modern construction due to its strength and cost-effectiveness. OSB must be properly stored and installed to prevent swelling from moisture exposure before shingles are applied.
Overhang (Rake & Eave)
The portion of the roof that extends beyond the exterior walls. Eave overhangs direct water away from the foundation; rake overhangs protect gable-end walls. Ohio building codes specify minimum overhang requirements for water management, particularly important for Lancaster's clay-heavy soil conditions.
W
Warranty (Manufacturer vs. Workmanship)
There are two types of roofing warranties: manufacturer warranties cover defective materials (typically 25–50 years for asphalt shingles) and workmanship warranties cover installation errors (typically 1–10 years from the contractor). Ohio homeowners should always request both in writing. Read our full Ohio Roof Warranty Guide to understand coverage gaps.
Wind Uplift Rating
A standardized measurement of a roofing system's resistance to wind forces, expressed in pounds per square foot (psf). Ohio experiences wind events exceeding 90 mph in severe storms, making wind uplift ratings critical. Most residential asphalt shingles carry Class D (90 mph) or Class H (150 mph) ratings under UL 2218 testing standards. Learn more about Ohio wind and hail damage.
Water Infiltration
The penetration of water through the roof assembly into the building structure. Water infiltration is the root cause of most roofing damage claims and can lead to mold growth, structural rot, and insulation failure. Early detection through annual professional roof inspections can prevent thousands in repair costs.
Have Questions About Your Roof?
Our roofing experts are here to help. Get an inspection and honest assessment from Lancaster's most trusted roofing team.