Roofing & Construction Glossary

Has a roofer ever used a word you were too polite to ask about?

Flashing, soffit, underlayment, square, valley. You nodded, wrote something down and hoped the quote would explain itself. It rarely does, and a homeowner who does not know the vocabulary cannot tell whether a price covers the right work.

I am Timothy Parks, and I keep this glossary for the people I work for in Dresden and across Weakley County, Tennessee. Every term below is explained in plain language, with a note on why it matters on an actual West Tennessee roof, barn or house. Read it straight through if you like, or skip to the letter you need. When a word still does not make sense, my phone line, (407) 383-9118 is the fastest way to ask me.

Why does the vocabulary matter before the work starts?

A roof is not one thing. It is a stack of layers and a collection of edges, joints and openings, each doing one job. When water gets in, it nearly always gets in at a joint or an edge, not through the middle of a sound shingle. So the words that describe edges and joints are the ones that matter most when you are trying to understand a leak or a quote.

Knowing a few terms also changes the conversation. Instead of saying that the roof leaks near the chimney, you can say the flashing at the chimney looks lifted. Instead of agreeing to replace everything, you can ask whether the decking was inspected and whether the underlayment is part of the scope. Questions like those are the sign of an informed owner, and any honest contractor, me included, should welcome them.

The table below shows how a roof is built from the bottom up, in the order the layers go on. Keep it in mind as you read the entries that follow.

What do the terms from A to D mean?

Architectural shingle

A laminated, multi-layer asphalt shingle, also called a dimensional shingle. It is thicker than a 3-tab and gives the roof a textured look. Many homeowners choose it because the extra thickness holds up better in wind, though the installation details still matter more than the shingle name.

Asphalt shingle

The most common residential roof covering. A fiberglass or organic mat is saturated with asphalt and topped with mineral granules that protect against sun. You will see it on a great many houses in this part of the state.

Built-up roof (BUR)

A flat or low-slope roof made from several alternating layers of asphalt and reinforcing fabric, often topped with gravel or a cap sheet. You see it on older commercial buildings and some flat sections of homes.

Counterflashing

A second layer of flashing set into or over base flashing at a wall or chimney. It covers the top edge of the first layer so water cannot slip behind it.

Decking

The structural boards or panels, usually plywood or OSB, fastened to the rafters or trusses. Shingles attach to the decking, so a soft or rotted deck means the roof cannot be fastened properly no matter how good the shingles are. Also called sheathing.

Drip edge

A metal flashing along the eaves and rakes that sends runoff away from the fascia and into the gutter. Without it, water tends to curl back under the first row of shingles and rot the wood behind.

Which terms from E to J come up most often?

Eave

The lower edge of the roof, where it overhangs the wall. Gutters mount here, and so do many of the problems I find, because water concentrates at the eave.

EPDM

A durable synthetic-rubber membrane used on flat and low-slope roofs. It comes in large sheets, so there are fewer seams to fail than with some other flat-roof products.

Fascia

The horizontal board along the lower edge of the roof that covers the rafter ends and carries the gutter. When fascia is soft, the gutter sags and the problem spreads.

Fastener

A nail, screw or clip used to hold roofing to the deck or structure. The right type and pattern are critical for wind resistance. Too few, too high on the shingle or driven too deep, and the roof will not hold in a storm.

Felt

An asphalt-saturated paper or fiberglass layer laid over the deck as a secondary water barrier. People also call it tar paper.

Flashing

Thin metal pieces that seal and direct water at joints, valleys, walls, chimneys and roof penetrations. Failed flashing is the leading cause of roof leaks that appear in otherwise healthy roofs.

Gable

The triangular section of wall at the end of a pitched roof, between the two slopes.

Granule

The ceramic-coated mineral surfacing on an asphalt shingle. It shields the asphalt from ultraviolet light and adds color. Granules in the gutter are not always a problem, but a bare patch on a shingle is.

Gutter

A channel along the eave that collects rainwater and carries it to downspouts and away from the foundation. In clay soil, where water lingers, getting runoff away from the house is especially important.

Hip

The external angle where two sloping roof planes meet. A hip roof slopes down toward the walls on all sides.

Ice and water shield

A self-adhering waterproof membrane used at eaves, valleys and penetrations. It protects against ice backing up under shingles in winter and against wind-driven rain in spring storms.

Joist

A horizontal member that carries a floor or ceiling, spanning between walls or beams.

What do the terms from M to R mean on a real roof?

Metal roof

A roof system of metal panels or shingles in steel, aluminum or copper. It is valued for long life and performance in severe weather, and it suits barns, shops and many homes. See metal buildings for how it applies to outbuildings.

Modified bitumen

A rolled asphalt membrane reinforced with polymer additives for flexibility and strength on low-slope roofs.

OSB

Oriented strand board, an engineered panel of compressed wood strands widely used as roof decking. It handles moisture poorly when it stays wet, which is why leaks that go unnoticed can ruin it.

Pipe boot

A flexible collar that seals the roof around a plumbing vent or other round penetration. The rubber cracks from sun over time, and a cracked boot is one of the most common small leaks.

Pitch

The steepness of a roof, written as rise over run. A 6:12 pitch rises six inches for every twelve inches of horizontal run. Pitch decides which materials are suitable and how safe the roof is to work on. Also called slope.

Plywood

An engineered panel of thin cross-laminated veneers used as roof decking.

Pole barn

A post-frame building in which large posts carry the loads. It needs no interior load-bearing walls and is common for barns, garages and workshops. The pole barn page explains how these are built.

Purlin

A horizontal member running across rafters or trusses to support roof panels. Common in metal and pole-barn roofs.

Rafter

A sloped structural member running from the ridge to the eave that supports the roof deck.

Ridge

The horizontal line at the top where two sloping planes meet.

Ridge vent

An exhaust vent along the ridge that lets hot, moist air escape the attic and improves ventilation.

And the terms from S to V?

Slope

See pitch. Slope determines which roofing materials are appropriate.

Soffit

The underside of the roof overhang, often vented to draw fresh air into the attic. Soffit and ridge vent work as a pair.

Square

A unit of roofing measure equal to 100 square feet of roof area. Roofers use it to figure materials and labor, so when you see a quote described in squares, ask how many and how that number was reached.

Standing seam

A metal roof system with raised, interlocking vertical seams that hide the fasteners and shed water well.

Step flashing

Individual L-shaped metal pieces woven in with the shingles where a roof meets a vertical wall.

3-tab shingle

A flat, single-layer asphalt shingle with three tabs per strip, giving a uniform look. It is the thinner of the two common types.

TPO

A single-ply thermoplastic membrane for flat and low-slope roofs, known for its white, heat-reflective surface.

Truss

A pre-engineered triangular framework that supports the roof and spans the building without interior load-bearing walls.

Underlayment

The water-resistant or waterproof layer installed over the deck, beneath the shingles or panels, as a secondary barrier against moisture.

Valley

The internal angle where two roof slopes meet. Valleys carry a lot of water and are normally lined with flashing, which makes them a common place for leaks.

Which words show up in the inspection and storm conversations?

Beyond the parts of a roof, a few other terms appear whenever an inspection or storm repair is on the table. They are worth knowing before anyone writes you a proposal.

• Tarp. A heavy sheet fastened over damaged roofing to keep water out until a proper repair. It is temporary. See emergency tarp installation.
• Tear-off. Removing the existing roof covering down to the deck. Whether it is needed depends on the number of layers and the condition of what is under them.
• Uplift. The upward force that wind exerts on a roof. Fasteners and edges resist it.
• 4 point inspection. A report that looks at four systems of a house: roof, electrical, plumbing and heating and cooling. Read the 4 point inspection page for how I approach it.
• Wind mitigation. Features of a building that help it resist wind, such as roof shape, how the deck is fastened and how the roof connects to the walls. See wind mitigation inspection and report.
• Moisture intrusion. Water getting into a structure where it should not be. Dealing with it is the subject of water mitigation.

If a word in your proposal does not appear here, ask the contractor what it means. If the answer is vague, the scope is probably vague too.

How can I use this glossary when I read a quote?

Here is a simple way to turn vocabulary into protection. When you receive a written proposal for roof work, look for each of the words below. If one is missing, ask why.

1. Does it say what is happening to the old roof covering, removed or covered over?
2. Does it mention the decking, and what happens if rotted sections are found?
3. Does it name the underlayment and the flashing, or does it quietly leave them out?
4. Does it describe the drip edge, vents and pipe boots, the small parts that cause big leaks?
5. Does it say how the work will be measured, in squares or by another method?

None of these questions requires technical training. They are the questions an inspector would ask. I answer them in writing on every proposal I make, and you are welcome to compare my answers with anyone else's, and I encourage it. For a closer look at how I examine a roof before writing anything, see roof inspection, and for the repair side of the work, roof repair.

What extra terms help on barns, shops and storm-struck roofs?

The standard glossary covers roofs. Real properties around Dresden include a lot more than roofs, so here are the words I use most often on outbuildings, storm work and site preparation.

Cricket

A small peaked structure built behind a chimney or other wide obstruction to divert water around it instead of letting it pool behind.

Dormer

A framed projection that sticks out of a sloped roof, usually with a window. Each side wall of a dormer is a place where step flashing has to work properly.

Header

A horizontal framing member over a door, window or wide opening that carries the load above it. A sagging barn door header is a structural issue, not a cosmetic one.

Post base

The connection or footing at the bottom of a post. On pole buildings, rot at the post base is a common long-term problem in wet clay soil.

Girt

A horizontal wall member in a post-frame or metal building that ties posts together and gives wall panels something to fasten to.

Sheathing

Another word for the decking or wall panels that cover framing.

Grading

The slope of the ground around a building. Good grading carries water away; poor grading lets it collect against the foundation.

Brush hog

A heavy rotary cutter pulled behind a tractor to cut brush and tall growth. It is one of the tools used in brush clearing.

Chipping

Running cut limbs and brush through a machine that reduces them to mulch so they do not have to be hauled.

Moisture meter

A handheld tool that reads the water content of wood or drywall. It helps tell a dry surface from one that only looks dry.

Words alone do not make a roof, of course. They are only a way to describe what is physically there, and every one of them points to something you can see or touch. If you can find the flashing, the vent and the drip edge on your own house from the ground, you already know more about your roof than many owners do. Each of these terms ties back to a service on this site. If you are weighing a project in one of these areas, look at site work, brush clearing or garages for what the job involves.

Which credentials do I hold?

These are the credentials I hold, listed as issued. They are Florida credentials, listed as facts about me and not as a statement about any other state.

• Florida Building Contractor, CBC059592
• Florida Roofing Contractor, CCC1327217
• Florida Home Inspector, HI4878

Ask me what any of them covers and I will tell you plainly.

Common questions