52 Roofing & Exterior Terms Every Maryland Homeowner Should Know

An L-shaped strip of metal flashing installed along the eaves and rakes of a roof. It directs water away from the fascia and into the gutter, preventing water from wicking behind the gutter board and rotting the roof deck. Maryland IRC code (R905.2.8.5) requires drip edge on all new asphalt shingle roofs.

A self-adhering rubberized membrane installed along eaves, valleys, and around penetrations to block water that backs up under shingles during ice damming. Maryland code requires it to extend 24 inches inside the warm wall line. Without it, even a well-installed roof leaks during the first freeze-thaw cycle.

The waterproof layer between the roof deck and the shingles. Modern synthetic underlayment (e.g., Owens Corning ProArmor) replaces traditional 15-lb felt, lasts longer, and resists tearing in wind. A roof is only as good as its underlayment, which is why JDH spec'd it on every replacement.

The structural sheathing nailed to the rafters, forming the roof deck. Standard thickness is 7/16-inch or 5/8-inch. OSB rotted by long-term leaks must be replaced before re-shingling. JDH inspections include a deck-condition check; estimates flag any sheets that fail the screwdriver test.

The horizontal board running along the eave that the gutter attaches to. Wood fascia rots when drip edge is missing or gutters overflow. JDH wraps fascia in aluminum coil stock during a roof replacement, which protects the wood for decades and matches the trim color.

The horizontal panel under the eave, between the fascia and the wall. Vented soffit panels feed cool intake air into the attic, balancing the hot air escaping at the ridge. Clogged or solid soffits are the #1 cause of premature shingle aging in Maryland attics.

A continuous vent installed along the peak of the roof that allows hot, moist attic air to escape. Pairs with soffit intake vents to create balanced attic ventilation. A roof without working ventilation cooks the shingles from below, voiding manufacturer warranties and shortening lifespan by 5-10 years.

The internal angle where two roof slopes meet. Valleys carry concentrated water flow and are the most common leak point on any roof. JDH installs either a closed-cut valley (woven shingles) or an open metal valley (W-profile) depending on pitch and manufacturer spec.

Thin metal pieces (aluminum, copper, or galvanized steel) installed at every roof transition: chimneys, walls, valleys, vent stacks: to direct water away from the joint. Failed flashing is the cause of 90% of older-roof leaks. Step flashing and counter-flashing are the two most common types.

The steepness of a roof, expressed as inches of rise per 12 inches of run (e.g., "6/12 pitch"). Pitch determines which materials can be used: asphalt shingles need 2/12 minimum, lower slopes require modified bitumen or TPO. Most Maryland homes are 4/12 to 9/12.

A roof style where all sides slope downward to the walls, with no vertical ends. Hip roofs are wind-resistant (FEMA-preferred for hurricane zones) but cost 10-15% more than gable roofs because they require more material and complex hip-and-ridge shingle work. Common in Annapolis colonials.

The triangular wall section between the two sloping sides of a peaked roof. A gable end can be vented (gable vents) or part of the wall cladding. Maryland's typical center-hall colonial and Cape Cod home both have prominent gables.

A small peaked structure built on the up-slope side of a chimney to divert water around it instead of letting it pond. Code requires a cricket on any chimney wider than 30 inches. Missing crickets cause chimney rot and the most expensive leak repairs JDH sees on inspections.

The reinforced strip on a shingle where nails must be placed to qualify for the manufacturer's wind warranty. High-nailed shingles (above the zone) routinely blow off in 60-mph gusts. JDH crews use chalk lines and air-gun depth gauges; warranty-grade installs hit the zone every time.

A laminated asphalt shingle made of two or more layers, creating a thicker, 3D appearance. Replaced 3-tab shingles as the residential standard around 2005. Owens Corning Duration and Duration Storm are the architectural lines JDH installs by default on Maryland homes.

The lower edge of a roof that overhangs the wall. The eave includes the fascia, soffit, drip edge, and the first foot of shingles. Most water damage on aging roofs starts at the eave because ice dams form here. A 24-inch ice-and-water shield extension up from the eave is code-required.

A small air gap (typically 3/8 inch) between the siding and the wall sheathing, created by furring strips or specialized clips. The gap lets any water that gets behind the siding drain and dry. Required for warranty on most fiber-cement and engineered-wood claddings.

A J-shaped vinyl or aluminum trim piece that receives the cut edges of siding panels around windows, doors, and corners. Properly back-flashed J-channel keeps water from running into the wall. Cheap installations skip flashing under the J and create the textbook "siding leak around window" problem.

A composite cladding made of cement, sand, and cellulose fibers, manufactured by James Hardie and others. Resists rot, fire, and termites; lasts 30-50 years; takes paint well. JDH is a James Hardie Elite Preferred contractor for Maryland and Virginia.

A horizontal cladding panel installed under the eave, either solid or perforated for ventilation. Available in aluminum, vinyl, and fiber cement. Perforated soffit feeds intake air into the attic; solid soffit is used on gable returns and porch ceilings where no ventilation is needed.

A small Z-shaped piece of metal installed above a window or door to shed water onto the siding face instead of into the rough opening. Missing drip caps are the most common cause of window-frame rot in 1980s-90s Maryland homes.

The water-resistive barrier installed behind the siding to block bulk water while allowing vapor to escape. Tyvek and ZIP-Wall are common. Without proper seams and flashing tape, housewrap can actually trap moisture and accelerate sheathing rot.

Priming the back face of wood or fiber-cement siding before installation, sealing it against moisture absorption from the wall side. James Hardie warranty requires back-priming on field-cut edges. Skipping this step is why some 5-year-old Hardie installs swell at the cut ends.

The manufacturer-mandated nail pattern (count, spacing, edge distance, and blind vs face-nail) required for warranty validity. James Hardie calls for ring-shank nails at 12 to 16 inches on center with 3/8-inch edge distance; ProVia vinyl specifies center-of-slot nailing with room for thermal movement. Most siding warranty denials trace to the wrong fastener type, over-driven nails, or skipped edge spacing. JDH crews work to the printed schedule on every job, not from memory.

The standard residential gutter profile in the U.S., named for its flat back and decorative K-shaped face. Available in 5-inch and 6-inch widths. JDH defaults to seamless 6-inch K-style on most Maryland roofs because it handles the heavier rainfall capacity of an Atlantic-coastal climate.

The vertical pipe that carries water from the gutter to the ground. Standard sizes are 2x3-inch or 3x4-inch. Undersized downspouts overflow during summer storms. JDH spec: one downspout per 40 linear feet of gutter, larger if the gutter drains a steep roof or large area.

A small diverter installed where a roof eave meets a sidewall, kicking water away from the wall and into the gutter. Missing kick-out flashing causes hidden sidewall rot: one of the top three insurance-claim issues in Calvert and Anne Arundel County storm damage inspections.

A screen, mesh, or solid cover installed over the gutter opening to keep leaves and debris out while letting water in. JDH installs Leaf Relief by Owens Corning, an aluminum micro-mesh system warrantied to never clog. Cheap plastic screens warp in 2-3 Maryland summers.

A decorative box at the top of a downspout that catches water from the gutter and channels it into the pipe. Common on historic Annapolis homes and high-end colonials. Functional and stylistic: also provides visual confirmation that water is flowing on inspection day.

A small concrete or molded plastic ramp placed at the bottom of a downspout to direct water away from the foundation. The minimum drainage standard. JDH recommends 4-6 foot extensions or buried PVC drains in clay-soil neighborhoods (most of Prince George's and Charles County).

How well a window resists heat transfer. Lower is better. Energy Star for Maryland requires U-factor ≤ 0.27. ProVia Endure windows hit 0.22-0.25 depending on glass package. Compare to a builder-grade single-pane at 1.10: five times worse.

Glass with a microscopic metallic coating that reflects infrared heat. Keeps summer heat out and winter heat in, without darkening the room. ProVia ComforTech triple-pane includes two Low-E coatings; standard double-pane uses one. Cuts cooling bills 15-25% in Maryland.

A dense, inert gas pumped between insulated glass panes to slow heat transfer. About 35% better than plain air, with no maintenance. Standard on every ProVia Endure window. Krypton (more dense, more expensive) is available on triple-pane configurations.

The moving part of a window: the frame that holds the glass and slides up, down, or tilts in. A double-hung window has two sashes (upper and lower). Worn sash balances are the #1 reason older windows are hard to open or won't stay up.

The vertical or horizontal divider between two adjacent window units, typically structural. Different from a muntin, which is a decorative grid inside a single window. Often confused on estimates: ask which one a contractor means.

The white-and-blue sticker on every new window listing U-factor, SHGC (solar heat gain), VT (visible transmittance), and air leakage. Third-party tested. The NFRC label is the only apples-to-apples comparison between window brands.

How much solar heat passes through a window. Lower is better for cooling-dominated climates. Maryland's mixed climate makes 0.25-0.30 the sweet spot: blocks most summer heat but lets winter sun in. Most ProVia Energy Star packages hit this range.

The flat panel of a door itself, separate from the frame and hardware. Available in steel, fiberglass, or wood. ProVia Signet fiberglass slabs replicate stained wood and resist Maryland humidity without warping: the most common entry-door replacement JDH installs.

The horizontal piece of an exterior door frame that the door closes against at floor level. Adjustable thresholds tighten the weather seal as the door ages. ADA-compliant low-profile thresholds are required on most new commercial work but optional residentially.

The flexible foam, rubber, or pile that seals the gap between a door slab and its frame. The fastest-aging part of any entry door. ProVia uses Q-Lon foam compression seal; cheap doors use vinyl that hardens in 2-3 winters. Worth replacing as a stand-alone project on 10+ year-old doors.

The unit of measure for thermal resistance. Higher R-value means better insulation. Maryland code (IRC Climate Zone 4A) requires R-49 in attics on new construction, R-30 minimum on retrofits. JDH owns thermal imaging cameras to verify R-value performance, not just the spec sheet.

A plastic or foil layer installed on the warm side of insulation to stop water vapor from condensing inside the wall or attic. In Maryland's mixed climate, vapor barriers must be carefully designed: wrong-side placement traps moisture and causes mold. Spray foam acts as its own barrier.

Cellulose or fiberglass insulation installed by being blown through a hose onto attic floors or into wall cavities. Fills irregular spaces better than batts. JDH uses cellulose (R-3.7/inch) for retrofits and recommends 16-18 inches of depth to hit Maryland's R-49 target.

Pre-cut rectangular pieces of fiberglass or mineral wool sized to fit between studs and joists. Faster than blown-in but easier to install with gaps that cut performance by 30%+. JDH spec: batts only in new-construction or open framing; blown-in for retrofits and tight cavities.

Perforations or vents in the soffit panel that allow cool air to enter the attic, balancing the hot air leaving at the ridge vent. Code requires 1 sq ft of net free area per 300 sq ft of attic. JDH attic inspections measure NFA: most older homes are 30-50% short.

A roof ventilation design where intake (soffit vents) equals exhaust (ridge vent). Imbalanced systems create dead zones, condensation, or even reverse airflow that drives water into the attic. Most Owens Corning shingle warranty claims denials come down to imbalanced ventilation.

Removing all old roofing layers down to the deck before installing new shingles. Required by Maryland code if the roof has 2+ existing layers. Tear-offs cost more than overlays but reveal sheathing damage and are the only install eligible for full manufacturer warranties.

Installing new shingles directly over a single existing layer. Faster and cheaper than tear-off but hides deck damage, adds dead load, and voids most manufacturer warranties. JDH almost never recommends overlays: they're a short-term decision that costs more in 7-10 years.

The forensic engineering standard for roof damage assessment. HAAG-certified inspectors are trained to distinguish hail strike from blistering, wind damage from manufacturer defect, and storm damage from age-related wear. Jim Dodson holds HAAG Master Level (cert #992109047, since 2021).

A single horizontal row of shingles running across the roof. The starter course goes on first (along the eave), then the field courses overlap up the slope. Each course covers 5/8 of the previous course on standard architectural shingles.

Manufacturer roof warranties come in three tiers: standard (material only, prorated), system (full system if installed by certified contractors), and limited-lifetime (transferable). Owens Corning Platinum Preferred contractors like JDH can offer the top-tier 50-year Platinum Protection warranty.

A structured inspection-reporting framework where every finding lists the visible Problem (e.g., shingle blistering on the south slope), the root Cause (insufficient attic ventilation creating heat stress), and the Consequence if left alone (warranty void, 5 to 10 year lifespan reduction, leak risk). Generic "we found X" reports skip the cause and consequence layers, which is exactly what insurance adjusters and warranty manufacturers actually need to act. JDH uses PPC on every inspection report.