Roof Terminology Guide

Roof Terminology

“Square” = 100 square feet of roofing surface area (10 ft x 10 ft). When a roof is said to be about 35 Squares, it usually refers to all of the roofing materials required to do the job including main field shingles, starter shingles, hip and ridge shingles, and waste. A rambler with a floor square footage of 2700 sq might require 35 squares depending upon the overhangs and the pitch of the roof. Garages can also add roof square footage.

“Bundle” = the number of packages of roofing material it takes to cover a square (100 square feet). 3-tab is 3 bundles per square, Dimensional is from 4–5, and Presidential shingles are 5–6 bundles per square. All cedar shakes and shingles are bundled at 5 bundles per square at the standard exposure — 10″ for shakes, 5″ for cedar shingles.

“Pitch” = The steepness of a roof is called the pitch and refers to the ratio of a roof’s vertical rise in inches to each foot (12 inches) of horizontal run. A roof with a pitch of 4/12 will rise 4″ vertically for every 12″ of horizontal distance.

The standard minimum pitch for composition shingles is a 4/12 pitch. Below 4/12 the manufacturers usually require a layer of Ice and Water Shield such as Certainteed Winterguard. Roofs with less than a 2/12 slope need to be re-roofed with a low slope roofing material such as torch down, hot-tar, PVC, or TPO membrane.

“Courses” — On pitched roofs, materials are installed horizontally. Each line of roofing material is called a course.

“Exposure” — The amount of roofing material exposed to the weather. Typically, composition shingles have about a 5 5/8″ exposure; 24″ cedar shakes have 10″ of the shake exposed to the weather.

Components of the Roof Structure

Ridge — The highest horizontal portion of the roof.

Gables — The end of the house where the edge of the roof goes straight up from the gutter to the ridge.

Rafters — Rafters can be on 24″ or 16″ centers. They support the roof sheathing.

Valleys — Where two slopes meet.

Hips — The roofline which slopes up toward the ridge at an angle, from an outside corner.

Fascia — The trim wood behind the gutters (usually a 1×6 or 1×8, either whitewood or tight-knot cedar).

Eaves — The area of the roof which extends out beyond the walls.

Soffit — The area beneath the overhang, behind the gutters. Usually vented.

Built-in gutters — Gutters enclosed in the eaves and lined with torch down, PVC, or hot tar. These often have scupper drains 2″ or 3″ in diameter that drain into the downspouts.

The Roof Decking

Decking or sheathing comes in several forms: solid planks, shiplap, skip sheathing with 1×4s, plywood, or OSB.

Shiplap — In some very old homes in Seattle, the roof deck consisted of planks previously used as forms for concrete foundations. Older roofs were also framed with 1×6 shiplap decking.

Skip or Spaced Sheathing — Usually 1×4 boards spaced every 4″. Common on most cedar shake and shingle roofs. Since cedar was abundant in the Northwest in the early 1900s, almost all roofs were made of shingles or shakes over skip sheathing.

CDX Plywood — CDX refers to exterior grade plywood made specifically for roofing. It comes in two common thicknesses: 1/2″ and 3/8″. Today, 1/2″ CDX is the norm and is required by most shingle manufacturers for their heavier shingles such as CertainTeed Presidential Shake or GAF Grand Sequoia.

OSB — 7/16″ Oriented Strand Board is less expensive than CDX and is very common on new construction homes. Structurally, it is just as strong as plywood; however, we are still biased toward CDX plywood. We offer the less expensive OSB as an option to save money when the situation is appropriate or at the customer’s request.

Underlayments

The purpose of the shingle underlayment is to provide an additional moisture-resistant layer to back up your roof shingles. For many years, “felt paper or tar paper” served as the leading type of shingle underlayment. As continual improvements in the building materials industry came about, synthetic underlayments emerged as the preeminent underlayment material used today. Though pricier than felt, synthetic underlayments are lighter in weight, better at lying flat (which prevents “wavy” shingle installations), and offer superior water resistance.

In a modern roof system, a professional contractor will install two different underlayments to maximize protection from the elements. The first is a waterproof ice and water membrane such as CertainTeed Winterguard, installed in areas where roof planes meet to form valleys and around other roof penetrations such as skylights, plumbing vents, chimneys, and roof-to-wall intersections. The second is a tear- and water-resistant material such as Diamond Deck, Tri-Built, or Safeguard 30 that covers the remaining areas of the roof deck and also provides a high-traction walking surface for safety during installation.

Ice and Snow Shield

Ice and Snow Shield underlayments feel like thin rubber or vinyl and are applied directly to the plywood with a “peel and stick” backing. They are waterproof and the material seals the nails and fasteners used to install the roofing. This is usually required on roof slopes from 2/12–4/12 pitch in order to maintain the shingle warranty.

On certain roofs we are now using it in the valleys, around pipes, chimneys, and skylights, and sometimes along the eaves to prevent problems with ice dams. In the Northwest, ice dams have been pretty rare due to the minimal snow we get in the winter — however, the last few winters have brought some significant snowfall. Assuming this may continue in the future, it seems like a reasonable added expense on a lifetime roof investment. Ask us about that option.

Roof Flashings

Step Flashing — Goes up the sides of chimneys, skylights, and dormers. Metal flashing goes up under the siding or counter flashing about 4″ and under each course of shingles or shakes. It should always be replaced during a re-roof whenever possible.

Drip Edge — Along the gable ends, this metal covers the exposed edge of the plywood or OSB.

1×3 Starter Metal — Used along the eave of the roof where the sheathing hangs into the gutter. Prevents wind-driven rain from hitting the edge of the wood and trims the edge out nicely. The bottom edge is hemmed so anyone cleaning the gutters won’t cut their hands.

Saddle or Pan Metal — Usually 5″×13″ metal which sits behind the chimney or skylights. This extends out a few inches beyond the corner of the chimney or skylight to ensure water does not get close to the corner. We snip the bottom of the flashing at the outside edge to prevent water from beading back under the metal, and seal the joint with high-end caulking for additional insurance.

Roof-to-Wall Flashing — Metal which goes up under the siding and out over the shingles where the roof meets a wall (like at the bottom of a dormer or the bottom of chimneys or skylights). Sometimes we cannot replace it without damaging the siding — if so, we wire brush it and paint it, or reside.

Counter Flashings — The metal flashing on a brick chimney that is mortared in between the bricks and folds down over all the other flashings at the base of the chimney. It will usually outlast the roofing shingles and, if painted regularly, can last many decades. If rusted and in poor condition, it needs to be replaced and we will include it in our estimate.

Plumbing Pipe Flashings — The flashings which slide down over the plumbing pipes on the roof. These pipes equalize the pressure in the plumbing system. Flashings come in three versions: all rubber, galvanized metal with a rubber boot, and all lead. We use lead flashings and lead caps on all our roofs as they last essentially forever — or at least as long as the highest end shingles. Flashings with a rubber sleeve tend to crack and split at about 20–23 years. We have had callbacks on these and we don’t like callbacks.

Valleys — For composition shingles, there are 3 types of valleys: woven, closed, and metal W valley. We use all-metal W-valley (14″ wide on each side, 26 gauge, brown or black baked enamel) on all roofs from 30-year 3-tab to Presidential and cedar shakes. It looks great and we never have valley problems.

Ventilation

Proper airflow in the attic space will prevent condensation from developing and rotting out the roof sheathing or plywood. It will help cool the home in the summer and prevent ice dams from building up in the winter.

The basic idea is to ensure that the attic temperature is close to the outside temperature. It is the difference in temperatures that causes condensation in the attic and snow melting above the eaves — then icing up at the gutters in winter.

Traditionally, gable vents at the ends of the house provided ventilation. Roof vents also supplied ventilation by convection when placed at the top of the roof just below the ridge, usually on the backside where they would be less visible. Soffit vents help improve this airflow and are now code. Ridge vents were initially developed to vent cathedral ceiling areas where it was not reasonable to install a roof vent every 2 feet. As they became more common and better looking, they are now the norm and are used whenever possible. On hip roofs which sometimes have limited ridge sections, roof vents must still be installed to provide adequate outflow.

5 Signs Your Roof Needs Replacing

Your roof is one of the most important components of your home. Knowing when it needs replacing — not just repairing — can save you from costly water damage and structural problems.

1. Your Roof Is Over 20 Years Old

Most asphalt shingle roofs last 20-25 years. If yours is approaching or past that age, it may be time to plan for replacement even if there are no obvious problems yet.

2. Shingles Are Curling or Buckling

Shingles that curl at the edges or buckle in the middle are past their lifespan. This typically happens due to moisture, heat, or age-related wear.

3. You Have Granules in Your Gutters

Asphalt shingles shed granules as they age. If your gutters are full of dark, sand-like granules, your shingles are deteriorating.

4. Daylight Visible from the Attic

If you can see daylight through your roof boards when in the attic, water and cold air can get in too. This is a serious structural issue.

5. Persistent Leaks After Repairs

If you have had repairs done but leaks keep recurring in different spots, your roof system has failed and needs replacement — not more patches.

Understanding WA Roofing Permits in King and Snohomish Counties

Whether you need a permit to re-roof your home in Washington depends almost entirely on where the house sits. Permitting is handled locally — by your city if you are inside city limits, by the county if you are not — and the answer genuinely changes from one side of a boundary to the other.

In unincorporated King County, a standard re-roof usually needs no permit at all. In unincorporated Snohomish County, it usually does. Inside city limits, every city sets its own rule.

We have been pulling roofing permits across King and Snohomish counties since 1983. Here is what actually triggers a permit, what happens at inspection, and what we handle for you.

Do I Need a Permit to Replace My Roof?

Short answer: it depends on your jurisdiction and on whether the work is structural. Like-for-like replacement is often exempt. Anything that touches the roof sheathing, changes the type of material, or adds significant weight generally is not.

Three questions decide it:

• Who has jurisdiction? A city, if your address is inside city limits. Otherwise the county — and King and Snohomish counties start from opposite defaults.
• Are you touching the sheathing? Removing or replacing the plywood or boards under the roofing is structural work. It needs a permit and an inspection almost everywhere.
• Is the new roof heavier? Swapping a light material for tile or slate adds dead load to a frame that was engineered for something else.

Everything below is the detail behind those three questions.

Unincorporated King County

Standard re-roofing on detached one- and two-family houses in unincorporated King County generally does not require a building permit. The county’s own guidance lists replacement of roofing or siding for detached one- and two-family houses as work that is exempt.

No permit needed for:

• Tear-off and replace. An ordinary residential re-roof.
• Overlay. Adding a layer over the existing roofing, as long as it stays inside the structural weight limit.
• Minor repairs. A few compromised shingles, or a localized leak.

A permit is required for:

• Commercial and multi-family buildings. Apartments, condos, and commercial structures always need one for roofing work.
• Environmentally critical areas. A steep slope, wetland, or protected shoreline carries its own review, and the roofing exemption does not apply.
• A real increase in weight. Going from a lightweight material to heavy tile or slate raises the roof’s dead load. King County code sets the trigger at more than 5 pounds per square foot of added cumulative dead load.

Unincorporated Snohomish County

Snohomish County runs the opposite default. In unincorporated areas a re-roof permit is required unless the work fits inside a specific exemption.

Exempt from permit:

• An overlay on a residential structure, up to a maximum of two total layers of roofing material.
• A complete tear-off and replacement using the same type of roofing material, provided the roof sheathing is not removed or replaced.
• Roof repairs.

Permit required if you are:

• Replacing roof sheathing.
• Changing the type of roofing material.
• Exceeding the maximum layer limit or the weight limit.

Inside City Limits, the Rules Vary

If your address is inside a city, that city — not the county — decides. The rules differ meaningfully from one to the next, which is why we do not publish a single blanket answer for the region.

Seattle is a good example of why that matters. SDCI does not require a re-roof permit for a one- or two-family home or townhouse where the only change to the building envelope is adding or replacing insulation to an equal or better value. A permit is needed once the work alters the envelope some other way — roof pitch, new skylights, rooftop equipment, or structural deck work — and for commercial or multifamily work over 500 square feet.

We keep a page for every city we work in, with that city’s permit office, application portal, and requirements. Start at our roofing permit directory, or go straight to Seattle, Bellevue, Kirkland, Redmond, Woodinville, or Everett.

On cost: most of these jurisdictions calculate the permit fee from the valuation of the work rather than charging a flat rate, so a larger or more complex roof costs more to permit than a small rambler. Across King and Snohomish counties they generally run $150 to $600. Check your city’s published fee schedule before you budget — or ask us, and we will confirm the real figure for your address with your estimate.

When a Re-Roof Becomes Structural Work

The most common way a routine job turns into a permitted one around here is cedar.

Older cedar shake roofs were installed over skip sheathing — spaced 1×4 boards with gaps between them. Composition shingles cannot be laid over that. So when we remove a cedar shake roof installed over skip sheathing, we install all new ½” CDX plywood before re-roofing. That is a structural change, and it requires an inspection.

The same applies if we find rot in the decking or rafters once the old roof is off. It changes the scope of the job, and we tell you before we proceed rather than after.

Why new construction and re-roofing are inspected differently

On a new build, the general contractor is responsible for obtaining all permits and scheduling inspections. The framing stays exposed to the weather for days at a time, which gives the inspector a thorough look at the plywood roof deck and the nailing patterns.

A re-roof is the opposite situation. We dry in the home with waterproof underlayment immediately after tear-off to protect it — we do not leave a roof exposed for any length of time. Where an inspection is required, the inspector does spot checks under the paper to confirm proper nailing.

That is the reason many cities and unincorporated county areas do not require an inspection when we tear off one or two layers of composition shingles and replace them with similar material: the plywood was already inspected for its nailing pattern when the home was built, the weight of the new roof has not changed substantially, and nothing structural has been altered. Some cities still inspect every roof to review nailing and ventilation regardless.

HOA Approval Is Separate From Your Permit

A homeowners association is not a permitting authority, but it can still stop your project. Many have covenants restricting the type of material, its weight, and even its color. Approval from the HOA is separate from the city or county permit — you need both, and the HOA is often the slower of the two.

In many neighborhoods where a homeowner is converting from a cedar shake roof to composition, the HOA specifically requires re-roofing with CertainTeed Presidential TL in select colors. Check your covenants before you settle on a product, not after.

Historic districts and landmarks. Seattle neighborhoods with landmark status — and homes individually listed — may need design review before a change of material or color. That adds time, so start early.

Who Pulls the Permit — and Why It Should Be Us

Where a permit is required, a licensed contractor should pull it. If a homeowner pulls it themselves as an “owner-builder,” they take on the liability for the work meeting code — including work they did not perform.

Be cautious of any contractor who suggests skipping a required permit to save money, or who asks you to pull it in your own name. Both are signals worth paying attention to. An unpermitted roof can surface later as:

• A problem at resale. Unpermitted work shows up in county records, or fails to show up when a buyer’s agent expects it to. Either way it can hold up a transaction.
• An insurance dispute. Carriers have declined claims on work that was never permitted or inspected.
• A retroactive permit. Cities can require you to open up completed work for inspection after the fact, at your cost.

Where a permit is required, its fee is a small fraction of a roof replacement. It is not the place to economize.

How Long Permitting Takes

Short answer: where a permit is required, expect it to add roughly one to two weeks before work starts — and because it runs in parallel with scheduling, it rarely delays the job itself.

We submit the application as soon as the contract is signed, so review happens while we are scheduling materials and crews. For a standard re-roof with no structural change, most jurisdictions turn it around inside a week.

The exception is a complex, historic, or critical-area property, where review can run several weeks. If that applies to your home, we will tell you at estimate time rather than after.

What We Handle for You

On every job, Stout Roofing takes care of:

• Determining whether your address needs a permit at all, and from whom
• Preparing and submitting the permit application
• Providing licensing, bonding, and insurance documentation
• Scheduling and meeting all required inspections
• Closing out the permit so it does not sit open on your property record

That last item gets missed surprisingly often. An open permit can cause exactly the same resale headaches as no permit at all. We close ours out.

Planning a project? Our roof cost calculator gives you a ballpark for the work itself, and we offer financing options if you would rather spread the cost.

Who to Contact

King County. Reach the Permitting Division at 206-296-6600 or PermitQuestions@kingcounty.gov. You can apply for permits, or check which jurisdiction your property actually falls under, at MyBuildingPermit.com.

Snohomish County. Planning and Development Services (PDS) is at 425-388-3311, or 3000 Rockefeller Avenue, Everett, WA 98201. Applications are submitted online.

Or just ask us. We have been pulling roofing permits across King and Snohomish counties for over 40 years and we know how each office works. If you are unsure whether your project needs a permit, call us at (425) 643-0888 or request a free estimate. We will tell you straight, before you commit to anything.

The requirements summarized above reflect King County and Snohomish County guidance current as of August 2026 and apply to unincorporated areas. Cities within both counties set their own rules. Jurisdictions update their codes and fee schedules periodically — confirm with your permit office, or ask us and we will confirm it for your address.