Roofing Terminology Glossary: 100+ Terms Explained

Understanding roofing terminology empowers you to communicate effectively with contractors, evaluate estimates accurately, and make informed decisions about your Pinellas County home. This comprehensive glossary covers over 100 roofing terms organized alphabetically, each with a clear definition and relevant Florida context where applicable.

Whether you are planning a roof replacement, getting repair estimates, or simply trying to understand your inspection report, bookmark this glossary as your go-to reference.

A

Algae Resistance - The ability of roofing materials to resist the growth of blue-green algae, which causes dark streaks on roofs. In Pinellas County's warm, humid climate, algae-resistant shingles with copper granules are strongly recommended.

Architectural Shingles - Also called dimensional or laminated shingles. These premium asphalt shingles have multiple layers that create a textured, three-dimensional appearance. They are thicker and more wind-resistant than standard 3-tab shingles, making them the most popular choice in Pinellas County.

Asphalt Shingles - The most common residential roofing material in the United States. Made from a fiberglass mat coated with asphalt and ceramic granules. Available in 3-tab and architectural styles. In Pinellas County, asphalt shingles must meet minimum wind resistance standards per the Florida Building Code.

Attic Ventilation - The system of intake and exhaust vents that allow air to circulate through your attic space. Proper ventilation is critical in Pinellas County to prevent heat buildup, moisture accumulation, and premature roofing material deterioration.

B

Barrel Tile - A semi-cylindrical roofing tile commonly seen on Mediterranean and Spanish-style homes. Also called S-tile or mission tile. Very popular across Pinellas County, especially in communities like Belleair and parts of St. Petersburg.

Blistering - Bubbles or raised areas on shingles caused by moisture trapped within the shingle during manufacturing or installation. Excessive blistering can indicate a defective product or ventilation problems.

Boot - See Pipe Boot.

Building Code - The set of regulations governing construction standards. In Pinellas County, the Florida Building Code (FBC) sets requirements for roofing materials, installation methods, and wind resistance that exceed most other states.

Built-Up Roof (BUR) - A flat or low-slope roofing system made of alternating layers of bitumen and reinforcing fabrics. Common on commercial buildings and some flat-roofed residential structures in Pinellas County.

Bundle - A package of shingles. Most architectural shingles require 3 to 4 bundles per square (100 square feet). The number of bundles needed varies by manufacturer and shingle type.

C

Cap Sheet - The top layer of a modified bitumen or built-up roofing system. Provides the weather-resistant surface and often contains granules for UV protection.

Caulk - A sealant used to fill gaps and joints around roof penetrations and flashing. Used as a supplementary seal, not a substitute for proper flashing installation.

Chalk Line - A straight reference line snapped on the roof deck to guide the alignment of shingles or tiles during installation. Proper chalk lines ensure consistent coursing and a professional appearance.

Clay Tile - Natural clay roofing tiles fired in a kiln. Extremely durable with lifespans of 50 to 100+ years. Heavier than concrete tile and requires a robust roof structure. Popular on upscale homes in Pinellas County.

Closed Valley - A valley where shingles from both sides of the intersection overlap, completely covering the valley flashing. Compare with open valley, where the metal flashing remains visible.

Collar - See Pipe Boot.

Concrete Tile - Roofing tiles made from Portland cement, sand, and water. More affordable than clay tile with similar durability. Common across Pinellas County and available in flat, barrel, and shake profiles.

Condensation - Moisture that forms when warm, humid air contacts a cooler surface. In Pinellas County attics, poor ventilation combined with high humidity can cause significant condensation, leading to mold growth and wood rot.

Counter Flashing - Metal flashing installed into a wall or chimney that overlaps the base flashing to create a two-piece waterproof system. Essential at every wall-to-roof transition.

Course - A horizontal row of shingles or tiles running the width of the roof. Proper coursing alignment ensures both aesthetic appeal and waterproofing performance.

Cricket - A small peaked structure built behind a chimney or at other locations where debris might accumulate. Diverts water around the obstruction and prevents pooling.

Curbing - A raised frame used to mount equipment on a flat roof, such as HVAC units. Proper flashing around curbing is essential for preventing leaks.

D

Decking - The structural surface (usually plywood or OSB) that covers the roof rafters and provides the base for all roofing materials. In Pinellas County, the Florida Building Code requires specific nailing schedules for decking attachment to resist hurricane-force winds. Also called roof sheathing.

Dimensional Shingles - See Architectural Shingles.

Dormer - A structural extension that projects from a sloped roof, usually containing a window. Dormers create additional interior space but also create complex flashing intersections that require careful waterproofing.

Downspout - The vertical pipe that carries rainwater from the gutter to the ground. Properly sized and placed downspouts are essential in Pinellas County where heavy tropical rains can overwhelm undersized drainage systems.

Drip Edge - An L-shaped metal strip installed along the eaves and rakes of a roof. It directs water away from the fascia board and into the gutter. Florida Building Code requires drip edge on all new roof installations in Pinellas County.

E

Eave - The lower edge of a roof that overhangs the exterior wall. Eaves protect walls from rain runoff and provide shade. In Pinellas County, eave overhang length affects both water protection and wind uplift vulnerability.

EPDM - Ethylene Propylene Diene Monomer, a synthetic rubber membrane used on flat and low-slope roofs. Durable and relatively affordable, EPDM is common on commercial buildings and some residential flat roofs in Pinellas County.

Exposure - The portion of a shingle, tile, or other roofing material that is visible and exposed to the weather after installation. Correct exposure is specified by the manufacturer and affects both appearance and performance.

F

Fascia - The vertical board that runs along the lower edge of the roof, just behind the gutter. Fascia covers the ends of the roof rafters and provides a mounting surface for gutters. In Pinellas County's humid climate, wood fascia is prone to rot and is often wrapped with aluminum or replaced with PVC.

Felt Paper - Also called tar paper. A traditional roofing underlayment made from organic or fiberglass material saturated with asphalt. While still used in some applications, synthetic underlayment has largely replaced felt paper for new installations in Pinellas County due to superior performance in heat and humidity.

Flashing - Thin metal material (usually aluminum, galvanized steel, or copper) installed at roof joints, penetrations, and intersections to prevent water infiltration. Proper flashing is one of the most critical elements of a waterproof roof system. In Pinellas County, wind-driven rain makes quality flashing installation especially important.

Flat Roof - A roof with a slope of less than 2/12. Despite the name, flat roofs have a slight slope for drainage. Common on commercial buildings and some modern residential designs in Pinellas County. Requires specialized membrane or built-up roofing systems.

Florida Building Code (FBC) - The statewide building code that governs all construction in Florida, including roofing. The FBC includes specific requirements for wind resistance, impact resistance in certain zones, and installation methods. Pinellas County enforces the FBC through its building department.

G

Gable - The triangular wall section formed between the two slopes of a gable roof. Gable roofs are common but more vulnerable to wind damage in hurricanes compared to hip roofs, which is a consideration for Pinellas County homeowners.

Gable Roof - A roof with two sloping sides that meet at a central ridge, forming a triangular shape at each end. Simple and cost-effective but less wind-resistant than hip roofs in Pinellas County's hurricane-prone environment.

Galvanized Steel - Steel coated with zinc to prevent corrosion. Used for flashing, drip edge, and some metal roofing panels. The salt air in coastal Pinellas County areas like Clearwater Beach and Indian Rocks Beach can accelerate corrosion of lower-grade galvanized products.

Granules - Crushed mineral particles embedded in the surface of asphalt shingles. Granules provide UV protection, fire resistance, and color. Finding granules in your gutters is normal during the first few rains after installation, but excessive granule loss on older roofs indicates deterioration.

Gutter - A channel installed along the eave to collect and direct rainwater to downspouts. Properly sized gutters are essential in Pinellas County to handle the heavy rainfall from tropical storms and summer thunderstorms.

H

Hip - The external angle formed where two sloping roof planes meet. A hip runs from the ridge to the eave at a diagonal angle.

Hip Roof - A roof where all four sides slope downward from the ridge to the eaves. Hip roofs are the most common roof shape in Pinellas County because they offer superior wind resistance compared to gable roofs. The Florida wind mitigation inspection rewards hip roofs with better insurance credits.

High-Velocity Hurricane Zone (HVHZ) - Areas in Florida (primarily Miami-Dade and Broward counties) with the strictest building code requirements. While Pinellas County is not in the HVHZ, it still has significant wind resistance requirements due to its coastal exposure.

Hot-Mopping - A method of applying built-up roofing where hot liquid asphalt is mopped between layers of roofing felt. Less common today as torch-applied and cold-adhesive methods have gained popularity.

I

Ice and Water Shield - A self-adhesive waterproof membrane applied to the roof deck in vulnerable areas. While ice dams are not a concern in Pinellas County, this peel-and-stick underlayment is widely used for secondary water resistance (SWR) to protect against wind-driven rain infiltration.

Impact Resistance - The ability of roofing materials to withstand impact from hail or wind-borne debris. Impact-resistant shingles are rated on a scale from Class 1 to Class 4, with Class 4 offering the highest protection. These ratings can help reduce insurance costs in Pinellas County.

Intake Vent - A vent that allows fresh air to enter the attic space, typically installed in the soffit or at the eave. Works in conjunction with exhaust vents to create proper attic ventilation.

J

Jack Rafter - A shortened rafter that runs from the ridge or hip to the eave. Jack rafters are common on hip roofs, which are the predominant roof style in Pinellas County.

L

Laminated Shingles - See Architectural Shingles.

Leak Barrier - A self-adhesive waterproof membrane installed at vulnerable points such as eaves, valleys, and around penetrations. The Florida Building Code specifies where leak barriers are required on Pinellas County roofs.

Low-Slope Roof - A roof with a pitch between 2/12 and 4/12. Low-slope roofs require different materials and installation methods than steep-slope roofs. Special underlayment and sealing requirements apply in the Florida Building Code.

M

Mansard Roof - A four-sided roof with two slopes on each side, where the lower slope is steeper than the upper. Uncommon in Pinellas County residential construction but seen on some commercial buildings and older homes.

Membrane Roofing - A roofing system using continuous sheets of synthetic material (TPO, PVC, EPDM) to waterproof flat or low-slope roofs. Common on commercial buildings and some contemporary homes in Pinellas County.

Metal Roofing - Roofing made from steel, aluminum, copper, or zinc panels or shingles. Metal roofs are growing in popularity across Pinellas County for their hurricane resistance, energy efficiency, and 40 to 70 year lifespan. Standing seam metal roofs score well on Florida wind mitigation inspections.

Modified Bitumen - A flat roofing material made from asphalt modified with rubber or plastic polymers. Applied in rolls using heat, cold adhesive, or self-adhesive backing. Common on flat and low-slope roofs in Pinellas County.

N

Nailing Pattern - The specified number and placement of nails for attaching roofing materials. The Florida Building Code requires enhanced nailing patterns in Pinellas County (typically 6 nails per shingle instead of 4) to resist wind uplift during hurricanes.

Nail Pop - A condition where a nail works its way upward through the roofing material, creating a raised bump and potential leak point. Nail pops can result from improperly driven nails, wood shrinkage, or thermal expansion.

NOA (Notice of Acceptance) - A certification required in the High-Velocity Hurricane Zone indicating that a product has been tested and approved for use. While Pinellas County is not in the HVHZ, many products used locally carry NOA approval as a mark of quality.

O

Open Valley - A roof valley where the metal flashing is left exposed rather than covered by shingles. Provides excellent water flow during heavy rains, making it a solid choice for Pinellas County roofs that face intense tropical downpours.

Oriented Strand Board (OSB) - An engineered wood panel made from compressed wood strands bonded with resin. Widely used as roof decking in Pinellas County. OSB is moisture-sensitive and can swell if exposed to prolonged water contact, making proper underlayment and timely completion critical.

Overhang - See Eave. The portion of the roof that extends beyond the exterior wall. Provides shade and wall protection but increases wind uplift surface area.

P

Peel-and-Stick Underlayment - A self-adhesive waterproof membrane that bonds directly to the roof deck. Used for secondary water resistance in Pinellas County, often required at eaves, valleys, and around penetrations. Also called ice and water shield or self-adhered membrane.

Penetration - Any object that passes through the roof surface, including vent pipes, exhaust fans, skylights, and satellite dish mounts. Each penetration requires proper flashing to prevent leaks.

Permit - Official authorization from the local building department to perform construction work. All roof replacements in Pinellas County require a building permit. Your licensed contractor should pull the permit and arrange all required inspections.

Pipe Boot - A prefabricated flashing piece that fits around plumbing vent pipes penetrating the roof. Made from rubber, lead, or thermoplastic. Pipe boots are one of the most common leak sources on aging roofs in Pinellas County due to rubber degradation in the sun.

Pitch - The steepness of a roof, technically expressed as the ratio of rise to span. Often used interchangeably with slope in everyday conversation. See also Slope.

Plywood - A wood panel made from thin layers (plies) glued together. Used as roof decking, plywood generally resists moisture better than OSB. Some Pinellas County homeowners specify plywood decking for its superior performance in humid environments.

Ponding - Standing water that remains on a flat roof for more than 48 hours after rainfall. Ponding indicates drainage problems and can lead to premature membrane failure, leaks, and structural issues.

R

Rafter - A structural framing member that runs from the ridge board to the eave, supporting the roof deck. Rafters bear the weight of all roofing materials and must be sized appropriately for the span and expected loads.

Rake - The sloped edge of a roof along the gable end, running from the eave to the ridge. Rake edges require drip edge flashing and proper sealing to prevent wind-driven rain infiltration.

Re-Roof - Installing new roofing materials over the existing roof without a complete tear-off. Florida law and the Florida Building Code limit re-roofing to a maximum of two layers total. If your Pinellas County home already has two layers, a full tear-off is required.

Ridge - The horizontal line where two sloping roof planes meet at the highest point of the roof. The ridge is the peak of your roof.

Ridge Cap - Specially designed shingles or tiles installed along the ridge to cover the joint where the two roof slopes meet. Ridge caps are vulnerable to wind damage in Pinellas County and should be installed with enhanced adhesive or mechanical fasteners.

Ridge Vent - A ventilation opening along the ridge that allows hot air to escape from the attic. Works with soffit vents to create passive air circulation. Ridge vents are the preferred exhaust ventilation method in Pinellas County because they provide uniform airflow along the entire ridge.

Roll Roofing - Asphalt roofing material sold in rolls, typically used on low-slope roofs or outbuildings. Less durable than shingles with a lifespan of 5 to 15 years. Not recommended for primary residential applications in Pinellas County.

Roof Deck - See Decking.

Roof-to-Wall Connection - The structural attachment between the roof framing and the wall framing. In Florida, this connection is evaluated during wind mitigation inspections. Hurricane clips or straps provide stronger connections than toe-nailing alone and earn better insurance credits.

S

Saturated Felt - See Felt Paper.

SBS Modified Bitumen - Styrene-Butadiene-Styrene modified asphalt roofing. SBS modifiers give the material rubber-like flexibility that performs well in temperature variations. A common flat roof material in Pinellas County.

Secondary Water Resistance (SWR) - A layer of waterproofing protection beneath the primary roofing material that prevents water intrusion if the outer layer is compromised during a storm. The Florida Building Code requires SWR for new roof installations in Pinellas County to protect against wind-driven rain.

Sheathing - See Decking.

Shed Roof - A single-slope roof, also called a lean-to roof. The simplest roof form, sloping in only one direction. Sometimes used for additions, porches, or modern architectural designs.

Slope - The measure of roof steepness expressed as inches of vertical rise per 12 inches of horizontal run. For example, a 6/12 slope rises 6 inches for every 12 inches of horizontal distance. Most Pinellas County homes have slopes between 4/12 and 8/12.

Soffit - The underside of the roof overhang. Soffits often contain vents that allow air intake for attic ventilation. In Pinellas County, soffit vents work with ridge vents to create airflow that reduces attic temperatures and moisture buildup. Vinyl or aluminum soffits resist moisture better than wood in our humid climate.

Square - A unit of measurement equal to 100 square feet of roof area. All roofing materials and labor are priced per square. See our cost per square guide for current pricing in Pinellas County.

Standing Seam - A metal roofing system where panels are connected by raised, interlocking seams. The fasteners are hidden beneath the seams, eliminating exposed screw holes. Standing seam metal roofs offer excellent wind resistance and are highly rated on Florida wind mitigation inspections.

Starter Strip - A row of roofing material installed along the eave before the first course of shingles. The starter strip provides adhesive and sealing at the most wind-vulnerable edge of the roof.

Step Flashing - Rectangular pieces of metal flashing woven into shingle courses where a roof meets a vertical wall. Each piece overlaps the one below to create a stair-step waterproofing system.

Storm Chaser - An unlicensed or out-of-state contractor who follows storms seeking quick roofing jobs. Pinellas County sees an influx of storm chasers after hurricanes. Always verify a contractor's Florida license and local presence before hiring.

Synthetic Underlayment - A lightweight, tear-resistant roofing underlayment made from polypropylene or polyester. Outperforms traditional felt paper in durability, UV resistance, and waterproofing. The preferred underlayment choice for Pinellas County roof installations.

T

Tar Paper - See Felt Paper.

Tear-Off - The process of removing existing roofing materials down to the deck before installing new materials. Most Pinellas County roof replacements involve a full tear-off to allow inspection and repair of the underlying decking.

Three-Tab Shingles - Basic asphalt shingles with cutouts (tabs) that create the appearance of three separate pieces. Thinner and less wind-resistant than architectural shingles. Increasingly uncommon in Pinellas County as architectural shingles offer better performance at a modest cost increase.

Tile Roof - A roofing system using individual concrete or clay tiles. Tile roofs are common across Pinellas County, offering 50+ year lifespans, excellent wind resistance (when properly installed), and distinctive aesthetics. They require a stronger roof structure due to their weight (900 to 1,200 pounds per square).

TPO (Thermoplastic Polyolefin) - A single-ply reflective roofing membrane used on flat and low-slope roofs. TPO is energy-efficient due to its white reflective surface, reducing cooling costs in Pinellas County's hot climate.

Truss - A prefabricated structural framework that supports the roof. Trusses distribute the roof load to the exterior walls and are engineered for specific spans and loads. In Pinellas County, trusses must be designed to meet Florida's wind load requirements.

U

Underlayment - A water-resistant or waterproof layer installed between the roof deck and the roofing material. Acts as a secondary barrier against moisture intrusion. Florida Building Code requires specific underlayment types and installation methods for Pinellas County, including enhanced requirements for the first few feet from the eave.

Uplift - The upward force exerted on a roof by wind. During hurricanes, uplift can tear roofing materials and even entire roof structures from a building. Proper nailing patterns, roof-to-wall connections, and material selection all help resist uplift in Pinellas County.

V

Valley - The internal angle formed where two sloping roof planes intersect. Valleys channel large volumes of water and are one of the most leak-prone areas on a roof. Proper valley flashing is critical in Pinellas County, where heavy tropical rains can send massive amounts of water through valleys.

Vapor Barrier - A material that resists the passage of moisture vapor. Less common in Pinellas County roofing compared to northern climates, but sometimes used in specific applications to control condensation in commercial buildings.

Ventilation - See Attic Ventilation. The system of air intake and exhaust that prevents heat and moisture buildup in the attic space. Florida Building Code requires a minimum ventilation ratio of 1:150 (1 square foot of net free ventilation area for every 150 square feet of attic floor).

W

Warranty - A guarantee covering roofing materials or workmanship. Manufacturer warranties cover material defects (typically 25 to 50 years for quality shingles). Workmanship warranties from the contractor cover installation quality (typically 2 to 10 years in Pinellas County).

Wind Mitigation Inspection - A Florida-specific home inspection that evaluates wind-resistant features of your roof and structure. The inspection uses a standardized form (OIR-B1-1802) to assess roof deck attachment, roof-to-wall connections, roof geometry, and secondary water resistance. Favorable ratings can save Pinellas County homeowners 20% to 45% on wind insurance premiums.

Wind Speed Rating - The maximum sustained wind speed a roofing material is tested and approved to withstand. Pinellas County requires roofing materials rated for a minimum of 150 mph wind speed in most areas, per the Florida Building Code.

Wind Uplift - See Uplift.

Woven Valley - A valley where shingles from both sides of the intersection are alternately layered across the valley. Similar to a closed valley. Woven valleys are less common in Pinellas County as many contractors prefer open or closed-cut valleys for better water flow.

Commonly Confused Terms

Frequently Asked Questions

What is a roofing square?

A roofing square is a unit of measurement equal to 100 square feet of roof area. Contractors use squares to estimate materials and labor costs. For example, a 2,000 square foot roof equals 20 squares. Most Pinellas County roofing estimates are priced per square.

What is the difference between roof pitch and roof slope?

Roof pitch and roof slope are often used interchangeably, but technically they differ. Pitch is expressed as a fraction of the roof span (such as 1/4 pitch), while slope is expressed as inches of rise per 12 inches of horizontal run (such as 6/12 slope). In everyday roofing conversation, most Pinellas County contractors use slope measurements like 4/12 or 6/12.

What is flashing on a roof?

Flashing is thin metal material installed at roof joints, penetrations, and intersections to prevent water intrusion. Common flashing locations include chimneys, vent pipes, skylights, wall-to-roof transitions, and valleys. In Pinellas County, proper flashing installation is critical because of heavy rain and wind-driven moisture during storms.

What is roof decking or sheathing?

Roof decking (also called sheathing) is the flat surface, usually plywood or oriented strand board (OSB), that covers the roof rafters and provides the base for underlayment and roofing materials. In Pinellas County, Florida Building Code requires specific nailing patterns for decking to resist wind uplift during hurricanes.

What is a wind mitigation inspection in Florida?

A wind mitigation inspection is a Florida-specific evaluation that assesses your roof and home for features that resist wind damage. The inspection examines roof deck attachment, roof-to-wall connections, roof geometry, and secondary water resistance. Passing this inspection with favorable ratings can save Pinellas County homeowners 20% to 45% on their wind insurance premiums.

Related Resources

• Roof Replacement Checklist: 25 Steps From Start to Finish
• How to Measure Your Roof: DIY Methods and Pro Tips
• Roofing Cost Per Square: Complete Material Price Guide