Ask ten homeowners to name the types of roofing on their street and most will say "shingles" and stop there. Walk any block in the North Hills, Bellevue or Squirrel Hill and you will see three distinct roofing systems: asphalt shingles on most houses, standing seam metal on a growing number of homes and additions, and flat membrane roofs on porches, garages, row houses and every commercial building between them. Those three systems cover almost every roof we install, and knowing how they differ is the first step toward a sound roof replacement in Pittsburgh.
This guide explains the three main types of roofing systems, the materials inside each one, how they hold up to Western Pennsylvania weather, and the related questions about roof classes, roof shapes and the 25 percent rule. We are Malick Brothers Exteriors, a family owned roofing company founded in 2022 by Ryan Malick and based at 500 Perry Highway in West View, so the examples below come from roofs we have put on.
What Are the Three Main Types of Roofing?
Roofing is grouped by how the system sheds water, and that gives you three categories:
- Shingle roofing: overlapping pieces (asphalt, slate, wood or synthetic) laid from eave to ridge so each course sheds water onto the one below. The standard pitched roof on Pittsburgh homes.
- Metal roofing: long panels or metal shingles fastened to the deck, usually standing seam steel on houses. Metal sheds snow and water faster than any shingle.
- Flat and low slope roofing: continuous membranes such as EPDM rubber, TPO, PVC and modified bitumen that form one watertight surface on roofs with little or no pitch.
Some guides list asphalt, metal and tile instead, but tile is another shingle style system and rare in our climate. The shingle, metal and membrane grouping is the one roofers use because it maps to how a roof is built, warranted and repaired. You can see every material we install on our roof materials page.
Shingle Roofing Systems: Asphalt, Slate and Wood
Shingle roofs are by far the most common of the different roofing systems in Allegheny County, and asphalt is on most of them. A complete asphalt system is more than the shingles you see: ice and water shield at the eaves and valleys, synthetic underlayment over the rest of the deck, starter strip, ridge cap and ridge ventilation. When every piece comes from one manufacturer the system can carry a longer warranty, which is why we install complete Atlas systems as an AtlasPro+ Platinum Select contractor and can offer the Atlas 50 year warranty on them. Learn more on our asphalt shingles page.
Three tab, architectural and designer shingles
Asphalt shingles come in three grades. Three tab shingles are the thin, flat product that covered most houses built from the 1960s through the 1990s. Architectural (dimensional) shingles are laminated in two layers, weigh more, resist wind far better and give the roof texture. Designer shingles are thicker still and imitate slate or shake. Nearly every roof we replace gets an architectural shingle such as Atlas Pinnacle Pristine, and lines such as Atlas StormMaster Shake carry a Class 4 impact rating for hail.
Do roofers still use three tab shingles?
Rarely. Three tab shingles are still sold for budget rentals and sheds, but their wind rating is low, their service life is the shortest of any asphalt product and several manufacturers have cut their three tab lines. The small saving buys a roof that may need replacing ten years sooner, so for a home you plan to keep, architectural shingles are the better value.
Slate and wood shingles
Natural slate is the original premium shingle system, and Pittsburgh still has thousands of early 1900s slate roofs in service in neighborhoods like Highland Park and Sewickley. Slate can last a century, but it is heavy and brittle, and the nails and flashing holding it usually fail first. Most "slate roof leaks" are flashing and fastener problems, which is why we offer slate roof repair rather than tearing off a roof with decades left. Wood shakes are uncommon here because damp shade feeds moss and rot.
Metal Roofing Systems: Standing Seam and Metal Shingles
Metal roofing has moved well beyond barns. The dominant residential product is standing seam steel: vertical panels with raised seams that lock together and conceal every fastener, so no exposed screws back out and leak. Exposed fastener panels (corrugated or ribbed) cost less and suit outbuildings, but their screws and washers need attention over time. Metal shingles and stone coated steel mimic shake or tile.
Panels are formed from galvanized or Galvalume steel with a baked on finish, or from aluminum, copper or zinc. Standing seam roofs commonly serve 40 to 70 years, shed snow quickly, resist fire and wind, and reflect summer heat better than dark asphalt. The trade offs are a higher upfront cost and the need for an installer who understands panel expansion, snow guards and trim details. We added metal roofing in 2023 and have since installed standing seam roofs in Wexford, Bellevue and across the North Hills. See our metal roofing page for colors and profiles.
Flat and Low Slope Roofing Systems Explained
Any roof with a pitch below about 2 in 12 cannot rely on shingles, because standing water works back up under the laps. These roofs need a membrane sealed into one continuous sheet, and Pittsburgh has many of them: row houses in Lawrenceville and the South Side, porch and dormer roofs on 1920s houses, garages, additions and nearly every commercial building.
The common types of commercial roofing systems are:
- EPDM (ethylene propylene diene monomer): a black synthetic rubber sheet with taped or glued seams. It stays flexible in the cold, tolerates freeze and thaw cycles and is the membrane we install most, as a MuleHide certified contractor using .060 inch EPDM. Details are on our EPDM roofing page.
- TPO (thermoplastic polyolefin): a white reflective single ply with heat welded seams, popular on large commercial roofs where cooling loads matter.
- PVC: a welded thermoplastic membrane with strong chemical and grease resistance, often used over restaurants.
- Modified bitumen: reinforced asphalt sheets applied in two plies. Our MuleHide 2 ply low slope system falls here and suits porch roofs and small additions.
- Built up roofing (BUR): the traditional tar and gravel roof, still found on older commercial buildings but seldom installed new.
- Silicone coatings: a restoration option that seals a sound existing membrane or metal roof instead of replacing it. We use MuleHide silicone coatings on commercial roofs and box gutters.
The right membrane depends on the deck, the drainage and how the roof is used. Our commercial roofing page covers the low slope systems we install.
Comparing the Types of Roofing Systems at a Glance
| System | Typical service life | Best roof pitch | Weight | Maintenance | Where we see it in Pittsburgh |
|---|---|---|---|---|---|
| Three tab asphalt | 15 to 20 years | 4 in 12 and steeper | Light | Moderate | Older roofs, rentals |
| Architectural asphalt | 25 to 30 years (longer with a full system warranty) | 2 in 12 and steeper | Light to medium | Low to moderate | Most homes |
| Standing seam metal | 40 to 70 years | 1 in 12 and steeper | Light | Low | New builds, additions, log and farm style homes |
| Natural slate | 75 to 100 plus years | 4 in 12 and steeper | Very heavy | Low, but repairs need a specialist | Pre 1940 homes in older neighborhoods |
| EPDM rubber | 25 to 30 years | Flat to 2 in 12 | Light | Low | Porches, garages, row houses, commercial |
| TPO, PVC or modified bitumen | 20 to 30 years | Flat to 3 in 12 | Light to medium | Low | Commercial, small low slope sections |
These are typical ranges for a properly installed roof. Ventilation, flashing quality and how quickly small problems are fixed matter as much as the material, and a yearly roof inspection catches most of them.
What Are the Three Classes of Roofing?
When a product sheet or insurance form mentions roof "classes," it means fire and impact ratings, not material types. Fire ratings run Class A (highest, carried by nearly all asphalt, metal and slate roofs), Class B and Class C. Impact ratings under the UL 2218 test run from Class 1 to Class 4, with Class 4 shingles surviving a two inch steel ball dropped from 20 feet. Some Pennsylvania insurers discount Class 4 shingles, so ask your agent before you choose a product.
What Are the Three Primary Roof Designs?
The shape of the roof decides which systems will work. The three primary roof designs are gable (two slopes meeting at a ridge, the classic Pittsburgh four square), hip (slopes on all four sides, common on 1950s ranches in Ross Township and McCandless), and flat or low slope. Many homes combine all three, each section needing its own system. The fourth common type is the gambrel, with the mansard close behind on older Victorian houses. The newest roofing products are better versions of the three systems above, such as Class 4 polymer modified shingles, not new shapes.
What Is the 25 Percent Rule in Roofing?
The 25 percent rule comes from the Florida Building Code: if more than 25 percent of a roof section is repaired or replaced within 12 months, the whole section must meet current code. Pennsylvania follows the International Residential Code through its Uniform Construction Code and does not use that trigger, but IRC Chapter 9 limits a roof to two layers of asphalt shingles and requires ice barrier at the eaves, so a large repair on a two layer roof often becomes a full tear off. That is why we give a written estimate for repair and for replacement so you can compare them.
What Is a Type 3 Roof?
"Type III" is a building construction class in the International Building Code, not a roofing material: noncombustible exterior walls, usually brick or block, with framing and a roof structure that may be wood. Most older brick storefronts, churches and apartment buildings around Pittsburgh fall into this class.
Types of Roofing Services
The types of roofing services are simpler than the systems. Replacement is a full tear off, deck repair, new underlayment, flashing, shingles or membrane and ventilation. Repair fixes a leak, storm damage or failed flashing on a roof that is otherwise sound. Inspection documents the roof for a sale, a claim or a yearly check. Gutters, soffit and fascia are usually done at the same time.
How to Choose the Right Roofing System for a Pittsburgh Home
Start with the roof itself: a steep gable gets shingles or metal, a flat porch or garage gets a membrane, and a house with both gets both. Then think about how long you plan to stay. An architectural shingle system will outlast most ownerships, while standing seam is the choice when you want to roof the house once. Pittsburgh freeze and thaw cycles are why every system we install gets ice and water shield at the eaves and valleys.
Cost is driven by more than the material: roof size and pitch, layers to remove, deck repairs, flashing, skylights, ventilation and gutters all move the number, so compare systems with a written estimate for each option on your actual roof. Finally, confirm the contractor is registered with the Pennsylvania Attorney General (look up any company, including our registration PA174918, at the PA HIC search), insured and certified by the manufacturer of the system proposed.
Frequently Asked Questions
What is the most common type of roofing on Pittsburgh homes?
Architectural asphalt shingles. They suit the steep gable and hip roofs that make up most of the housing stock, handle freeze and thaw cycles well, and carry a long warranty when installed as a complete system. Standing seam metal is the fastest growing alternative, and EPDM rubber is the standard on the flat porch and garage roofs attached to those same houses.
How many roofing systems are there?
Dozens of specific products, but they all fall into three systems: shingle (asphalt, slate, wood, synthetic), metal (standing seam, exposed fastener, metal shingle) and membrane (EPDM, TPO, PVC, modified bitumen, built up, coatings). Once you know which of the three your roof needs, the choice narrows to a handful of products.
Is a metal roof better than shingles in Pennsylvania?
Metal lasts longer, sheds snow faster and needs less maintenance, which makes it a strong choice if you plan to stay for decades. Architectural shingles cost less up front, are easier to repair and match most neighborhoods. Both perform well here over proper underlayment with ice and water shield at the eaves.
Can you put shingles on a flat roof?
No. Asphalt shingles need at least a 2 in 12 pitch, and even then they require doubled underlayment. On anything flatter, water sits behind the laps and leaks through. A low slope roof needs a membrane such as EPDM or two ply modified bitumen, which is why the porch roof on a Pittsburgh house is usually rubber while the main roof is shingles.
How long does an EPDM rubber roof last?
A properly installed .060 inch EPDM roof typically serves 25 to 30 years, and many go longer. Seams and flashing at walls, drains and penetrations fail first, so regular inspection and prompt seam repair extend its life. A sound EPDM roof can also be coated with silicone to add years without a tear off.
Talk to a Pittsburgh Roofer About Your Options
Whether your home needs an Atlas shingle system, a standing seam metal roof or an EPDM membrane on a flat section, we will walk the roof, explain which system fits and give you a free written estimate. Malick Brothers Exteriors is BBB A+ accredited, PA HIC registered and based in West View, serving Pittsburgh and the North Hills. Contact us to schedule your roof evaluation.
