How roofing products are made

Colorado Roof Guide has no business relationship with any company named on this page, as of October 2026. Brands appear only where a manufacturer or reliable source describes how the product is made.

Every roofing material starts as a raw ingredient: crude-oil asphalt, steel coil, clay, quarried stone, plastic resin or cedar logs. How a factory turns that into a roof decides how it handles the four things Colorado throws at it. Those are hail, strong sun at altitude, freeze-thaw cycles and downslope wind.

This page walks through each product family. For how the layers fit together on your house, start with how your roof works. For who makes what, see roofing manufacturers.

At a glance

Asphalt shingles

Most Colorado roofs are asphalt, so this is the longest section. A shingle is made on one long, continuous production line.

The mat

The core is a fiberglass mat: glass fibers held together with resin binders. It arrives in big rolls and is unwound at the head of the line. The mat gives the shingle its strength. When hail hits hard enough to fracture that mat, the shingle has lost function even if granules stay in place.

The asphalt

Asphalt comes from oil refining. Before it goes on the mat, makers "oxidize" it by blowing air through the hot asphalt to thicken it. IKO describes this as a balancing act. Too much blowing makes shingles brittle, and too little leaves them soft and easy to scuff in summer heat.

A fine mineral filler is mixed into this coating asphalt to improve weathering and fire performance. The mat is then soaked and coated on both sides.

Granules

While the asphalt is still hot, granules are dropped on and pressed in. They're crushed, screened rock. The exposed ones get a ceramic coating that gives them color. Their real job is blocking UV, which matters more here: the WHO says UV rises roughly 10% per 1,000 meters (about 3,300 feet) of elevation.

Specialty granules exist too. 3M, a major granule supplier, makes copper granules that resist algae, solar-reflective granules for cooler roofs, and smog-reducing granules. Copper granules fight the blue-green algae behind black streaks, which grow with dew and humidity. That's a smaller concern on a dry Front Range roof. Reflective granules are covered on our roof color page.

Back, sealant and lamination

The back gets fine sand or limestone-type powder so shingles don't stick together in the bundle. A strip of heat-activated sealant goes on, plus a plastic release film on the back so the sealant doesn't bond in the package. Installers don't need to peel that film off.

For architectural (laminated) shingles, two layers are glued together with a similar adhesive. IKO calls the top layer the "dragon tooth" and the bottom layer the "shim." That double layer is what gives the dimensional look.

The sealant only works once sun warms it on the roof. A roof installed in a cold Colorado month may not seal until a warm spell, and until then it's more vulnerable to wind. See asphalt shingles for wind ratings.

How impact-resistant shingles differ

Class 4 shingles start on the same line but change one of two things. Some change the asphalt, and some add reinforcement. A few do a version of both. Here is what each maker says about its own Class 4 line, as of October 2026.

SBS (styrene-butadiene-styrene) is a synthetic rubber. Blended into asphalt, it keeps the shingle flexible, so a hailstone is more likely to dent it than crack the mat. In 2014 research, IBHS found SBS-modified impact shingles outperformed traditional impact-resistant shingles at Class 4 impacts. Flexibility also helps in cold weather, when plain oxidized asphalt gets stiff.

Reinforcement backs the shingle with a tough layer that holds it together when struck. It can pass the same lab test, but it's a different way to get there.

Where shingles sold here are made

Shingles are heavy to ship, and GAF, for one, says its newest plant adds capacity close to end markets. Here's what we could confirm for Colorado and nearby states, as of October 2026.

• Owens Corning, Denver. OSHA establishment records list Owens Corning Roofing and Asphalt on Fox Street in north Denver under the federal industry code for asphalt shingle and coating materials manufacturing. A manufacturing database lists Duration and Oakridge shingles at that address. Trade press reported OSHA gave an Owens Corning asphalt plant in Denver its Voluntary Protection Program "Star" status. We didn't find Owens Corning's own page confirming the plant.
• Westlake Royal concrete tile, Henderson. MonierLifetile opened a $10 million concrete tile plant in Henderson in October 2002 to serve Colorado. A facility listing now shows the site under Westlake Royal Roofing Solutions, which took over Boral's North American roofing business in 2021.
• Malarkey. Plants in Portland, Oregon; South Gate, California; Oklahoma City; and Williamsport, Maryland. A new plant in Franklin, Indiana, was targeted to start shingle production in mid-2026.
• IKO. A shingle plant in Hillsboro, Texas, started production in late 2017 to serve the Southwest.
• GAF. GAF is building a shingle plant in Newton, Kansas, to make Timberline HDZ and ArmorShield II, with production expected in 2027. We found no GAF plant in Colorado.

We couldn't confirm plants near Colorado for CertainTeed, TAMKO or Atlas. Where a bundle was made is usually printed on the wrapper.

Underlayment and ice barriers

Older roofs used asphalt-saturated felt: paper or fiber soaked in asphalt. Most roofs now use synthetic underlayment. One example, CertainTeed RoofRunner, is a woven polypropylene base with a polyolefin layer and a polymer coating on the back. It's evaluated under ICC-ES criteria as an alternative to the ASTM D226 felt standard. Synthetics are lighter and don't wrinkle when wet.

Ice and water barriers are self-adhering sheets with a sticky layer of rubberized asphalt or butyl under a release liner. The adhesive seals around nails driven through it. Butyl can be made to handle higher temperatures. Rubberized asphalt can react badly with plasticizers in some sealants and membranes. With both, a formula tuned for heat tends to grip less in the cold, so installers follow the maker's temperature limits. Whether you need one at all depends on local code; see how your roof works.

Metal roofing

Steel and its coating

Residential metal panels usually start as steel coil run through a hot-dip coating line. There are two common coatings.

• Galvanized is zinc. The zinc corrodes in place of the steel at a fairly steady rate. G90 is a common coating weight.
• Galvalume-type coatings are about 55% aluminum, 43.5% zinc and 1.5% silicon. The aluminum mostly acts as a barrier, the zinc protects cut edges, and corrosion slows over time. AZ50 is about as thick as G90, and AZ55 is common outdoors.

Paint

After coating, the coil is primed and painted in the factory. Two paint families dominate.

• SMP (silicone-modified polyester) is the economy option.
• PVDF, sold under names like Kynar 500, must be at least 70% PVDF resin. Metal manufacturers describe it as the best at resisting fading and chalking, at a somewhat higher material cost.

Under strong high-altitude sun, paint system matters. Check the fade and chalk terms in the paint warranty, not just the panel warranty.

Panel forming and gauge

Painted coil is roll-formed into panels, either in a plant or on a portable machine in your driveway. On-site forming makes long single panels with fewer seams, but needs room for the machine and dry, calm weather.

• Exposed-fastener panels are screwed through the face. They're often 24, 26 or 29 gauge (lower number means thicker). Every screw is a possible leak point, and expansion can loosen them over time.
• Standing seam panels lock together at raised seams and attach with hidden clips, often in 22 or 24 gauge. Clips let the panel expand and contract, which helps with big Colorado temperature swings.

Thicker steel resists denting better, but metal can still dent cosmetically in hail. See metal roofs.

Stone-coated steel

DECRA describes its process this way. Structural steel is cut and stamped into shingle, shake or tile shapes and hot-dip coated with aluminum, zinc and silicon. Then it gets an acrylic resin coat, pigmented natural stone granules, a clear overglaze and a final cure. Westlake Royal's Unified Steel and Tilcor make similar products. The steel core takes the impact while the stone surface gives texture.

Concrete and clay tile

Concrete tile is sand, cement, water and iron oxide pigment. Eagle Roofing says its mix is pressed onto steel molds, dried in a kiln for about four hours and coated with a masonry sealer to limit white efflorescence. Eagle tests break strength hourly against a 300 psi code minimum and runs periodic freeze-thaw, fire, impact and wind tests. Concrete tile is heavy, so a switch from asphalt needs a framing check. See tile roofs.

Clay tile is formed and then fired. Ludowici, which makes tile in New Lexington, Ohio, says it fires at 2,100°F for 24 hours. It says its tile meets ASTM C1167 Grade 1, the clay tile standard's highest grade, with water absorption under 2%. Those are the maker's claims. Low absorption matters here because water soaked into a tile can freeze, expand and spall the surface.

Slate

Natural slate is quarried, not manufactured. In the Slate Valley on the Vermont–New York border, blocks are drilled and blasted out of open pits, then sawn with water-cooled diamond blades. Workers split each piece by hand with a hammer and chisel. That step is still manual. Trimmers then bevel the edges, and nail holes are punched from the back.

Slate also comes from Virginia and is increasingly imported from Spain, Brazil and China, which raises quality and testing questions.

ASTM C406 grades roofing slate by lab tests for water absorption, breaking strength and weather resistance. S1 slate is expected to last over 75 years, S2 40 to 75 years and S3 20 to 40 years. Industry guidance favors S1 for roofing. Ask for the grade in writing. See slate roofs.

Synthetic and composite roofing

Synthetic slate and shake are molded from polymers. Recipes differ:

• DaVinci says it uses virgin resins with UV and thermal stabilizers and a fire retardant, not recycled tires or bottles. It's made in Kansas, and production scrap is reground into starter tiles and hidden parts.
• Brava says its tile is compressed recycled plastics and other materials. It offers Class A or Class C fire versions, so check which one you're getting.

UV stabilizers are what keep a plastic roof from fading and going brittle in strong sun. Many synthetics carry Class 4 ratings. See synthetic roofing.

Low-slope membranes

Flat and nearly flat roofs use sheets instead of overlapping pieces, so seams are everything.

• TPO is a thermoplastic sheet with polyester or fiberglass reinforcement and a top layer with UV and heat stabilizers. Seams are heat-welded with hot air.
• PVC has a similar build but includes a liquid plasticizer for flexibility. Seams are heat-welded.
• EPDM is a synthetic rubber, black from carbon black. It's a thermoset: once cured it can't be melted, so seams are glued or taped.
• Modified bitumen is asphalt blended with polymer on a reinforcing mat. SBS versions are rubbery and stay flexible at lower temperatures. APP versions are more plastic-like and stiffer. They're installed by torch, hot asphalt, cold adhesive or self-adhesion, depending on product.

Cold flexibility and seam quality matter most on Colorado flat roofs, which see ponding, freeze-thaw and hail. See flat roofs.

Cedar shakes and shingles

The Cedar Shake and Shingle Bureau describes two main types:

• Handsplit shakes are split from cedar blocks, then run diagonally through a bandsaw. That gives each shake a split face and a sawn back.
• Tapersawn shakes are sawn on both faces.

Top-grade No. 1 shingles are all heartwood, clear and edge grain.

Untreated cedar burns. Fire-retardant cedar (the bureau's Certi-Guard label) is pressure-impregnated and can be used in Class A, B or C roof systems. The rating depends on the full assembly, so check details with the treater and your building department. In mapped wildfire areas, the Colorado Wildfire Resiliency Code requires a Class A roof covering or assembly. Treated cedar also calls for Type 316 stainless steel fasteners. See wood shake.

Marks to look for on the label

These codes on wrappers and spec sheets tell you what a product was tested for. All are lab tests. None is a promise about your roof in a real storm.

For hail, a quote should name both the exact product and its impact standard. Our hiring guide covers what else to get in writing, and insurance explains how ratings can affect premiums.

Common questions

Are any shingles made in Colorado?

Federal workplace records list an Owens Corning roofing and asphalt plant in north Denver under the asphalt shingle manufacturing code, though we didn't find Owens Corning's own page confirming it. Separately, a concrete tile plant in Henderson has made tile since 2002. We didn't find a Colorado shingle plant for GAF, CertainTeed, IKO, TAMKO, Atlas or Malarkey as of October 2026.

What is SBS in a shingle?

SBS (styrene-butadiene-styrene) is a synthetic rubber blended into the asphalt so the shingle stays flexible. Several Class 4 shingles use it, including GAF Timberline AS II, Owens Corning Duration FLEX and Malarkey Vista. Not every Class 4 shingle does; Owens Corning Duration STORM uses a reinforcing mesh on the back instead.

Is Galvalume better than galvanized for a metal roof?

They protect steel differently. Galvalume-type coatings (about 55% aluminum) act mostly as a barrier and corrode more slowly over time, while galvanized zinc protects steel by sacrificing itself at a steadier rate. Ask your installer which coating and coating weight the panel has, such as AZ50 or G90.

What should I look for on the shingle bundle?

Look for ASTM D3462 (the basic shingle standard), a D7158 wind class, UL 790 or ASTM E108 Class A fire, and UL 2218 or FM 4473 for impact. These are lab ratings, not guarantees. See Class 4 roofing.

Do algae-resistant granules matter in Colorado?

Less than in humid places. Copper granules fight the blue-green algae that cause black streaks, which manufacturers say grow with dew and humidity. On a dry Front Range roof, hail and sun usually matter more than algae.