“Asphalt vs fiberglass shingles” is a comparison that mostly does not exist anymore. Nearly every asphalt shingle sold in North America today is a fiberglass shingle. The real distinction is the mat inside the shingle: a fiberglass mat versus the older organic (felt) mat. Both are asphalt shingles. Organic-mat shingles were largely discontinued by 2012, so when a product page says “fiberglass shingle,” it is describing the reinforcement mat, not a material that competes with asphalt.
This guide clears up the terminology, then covers the differences that still matter when you compare a fiberglass-mat shingle to an organic-mat shingle: weight, fire rating, moisture behavior, and lifespan.
Are asphalt shingles and fiberglass shingles the same thing?
In most cases, yes. A fiberglass shingle is a type of asphalt shingle. Both are built from an asphalt-coated mat topped with mineral granules. “Fiberglass” refers to the reinforcing mat at the core, which is a woven glass-fiber mat instead of the older organic felt. Because organic-mat shingles have been phased out of North American production, almost any asphalt shingle you buy in 2026 is a fiberglass shingle whether the label says so or not.
The two shingle families are asphalt shingles built on two different mats:
- Fiberglass-mat asphalt shingles. A fiberglass mat is saturated and coated with asphalt, then surfaced with ceramic-coated granules. Covered by ASTM D3462.
- Organic-mat asphalt shingles. A cellulose felt mat (paper or wood fiber) saturated with asphalt, then surfaced with granules. Covered by the withdrawn ASTM D225.
So the honest version of the question is not “asphalt or fiberglass.” It is “fiberglass mat or organic mat,” and the market has already answered that for you. For a related terminology mix-up, see how asphalt vs composite shingles is the same trap on a different axis, and how composition shingles is just another name for the same product category.
What is a fiberglass shingle mat?
A fiberglass shingle mat is a thin, non-woven layer of glass fibers bonded with a resin binder that forms the structural core of the shingle. Asphalt is applied to both sides of this mat, and mineral granules are pressed into the top surface. The glass mat gives the shingle its tear strength and dimensional stability while using less asphalt than an organic felt of the same size.
The mat is why a fiberglass shingle can hit a Class A fire rating. Glass fibers do not burn, so the mat resists flame spread far better than a cellulose felt core. This is the single biggest safety reason the industry moved to fiberglass. Manufacturers reinforce the nail zone (GAF calls its version LayerLock, and the reinforced strip is often labeled StrikeZone) to improve pull-through resistance, a property tested directly under ASTM D3462.
What is an organic-mat shingle?
An organic-mat shingle uses a base of cellulose felt, made from recycled paper or wood fiber, saturated with asphalt. Because the felt soaks up asphalt, an organic shingle carries roughly 40% more asphalt by weight than a comparable fiberglass shingle. That extra asphalt made organic shingles heavier, more flexible in cold weather, and, for a time, valued in northern climates.
Organic shingles are now effectively obsolete. ASTM withdrew D225, the organic shingle specification, in 2012 because organic felt-reinforced shingles were no longer being manufactured in North America. You will still find them on older roofs installed before roughly 2010, and a handful of specialty products exist, but you generally cannot buy a mainstream organic shingle new today.
Fiberglass mat vs organic mat: the differences that matter
The practical differences come down to weight, fire performance, moisture behavior, and lifespan. Fiberglass wins on fire rating, weight, and moisture resistance. Organic historically won on cold-weather flexibility and tear toughness, which is why it lingered longest in northern markets before disappearing.
| Property | Fiberglass-mat shingle | Organic-mat shingle |
|---|---|---|
| Mat material | Glass-fiber mat | Cellulose felt (paper/wood fiber) |
| ASTM standard | D3462 (active) | D225 (withdrawn 2012) |
| Asphalt content | Lower | About 40% more |
| Weight | Lighter | Heavier |
| Typical fire rating | Class A achievable | Class C typical |
| Moisture resistance | Higher (glass does not absorb) | Lower (felt can absorb, curl) |
| Cold-weather flexibility | Lower | Higher |
| Availability in 2026 | Standard product | Effectively discontinued |
Weight and installation
Fiberglass shingles are lighter because the glass mat needs less asphalt to hold its shape. Lower weight means less dead load on the roof deck and easier handling on the roof. Organic shingles carried more asphalt, so a square of organic weighed more, which mattered on marginal framing and made bundles harder to carry. For most homes this difference is minor, but it favors fiberglass on older structures where load is a concern.
Fire resistance
Fiberglass shingles reach a Class A fire rating, the highest level under UL 790 (also tested as ASTM E108), because the glass mat does not feed a flame. Organic shingles typically rated Class C, since the cellulose felt core is combustible. Fire rating is not just a spec sheet number: some jurisdictions and some insurers treat roof fire class as a factor, and Class A is the benchmark most codes reference for wildfire-prone areas.
Moisture behavior
The organic felt mat can absorb moisture, which leads to swelling, curling, and blistering over time, especially with poor attic ventilation. A glass mat does not absorb water, so fiberglass shingles hold their shape better in humid and rainy climates. This moisture advantage is a large part of why fiberglass displaced organic across most of the country.
Lifespan
A modern fiberglass architectural shingle is typically warrantied in the 25 to 50 year range depending on the line, while the organic shingles of the past commonly ran 15 to 30 years before the moisture and curling issues set in. Real field lifespan depends far more on ventilation, installation quality, and climate than on the mat alone. For how manufacturer claims compare to observed field data, see the Roofing Material Market Share Report.
How to tell if your existing shingles are fiberglass or organic
If your roof was installed after about 2010, it is almost certainly fiberglass. To confirm on an older roof, check the mat and the weight. Fiberglass shingles show a light-colored, matted glass fiber layer on the back and along a torn edge; organic shingles show a darker, paper-like felt that tears more like cardboard.
- Check the install date. Post-2010 roofs are fiberglass by default. Organic production had largely ended by then.
- Look at a torn or cut edge. Fiberglass reveals fine white or translucent glass strands. Organic reveals a fibrous brown felt, like thick paper.
- Feel the weight and flex. Organic shingles are heavier and more flexible; fiberglass is lighter and slightly more rigid.
- Check the wrapper or paperwork. Product data or a leftover bundle wrapper will cite ASTM D3462 for fiberglass. A D225 reference indicates organic.
Does the fiberglass vs organic choice affect what you should buy?
For a new roof, there is no real choice to make: you are buying a fiberglass shingle. The decisions that matter now are within the fiberglass category, not between fiberglass and organic. Focus on shingle grade (3-tab, architectural, or designer), wind and impact rating, and warranty rather than the mat, because the mat is already fiberglass.
Where your energy is better spent:
- Shingle grade. Compare 3-tab, architectural, and designer lines. See types of asphalt shingles for how they differ in cost and lifespan.
- Impact rating. In hail regions, a Class 4 impact-resistant shingle can qualify for an insurance discount of roughly 20 to 25% in some states.
- Wind rating and warranty. Look at the labeled wind speed rating and the enhanced-warranty requirements, which usually hinge on using matched starter, ridge, and underlayment from the same manufacturer.
For a broader grounding in roofing terminology and how these product families fit together, start at the Learn About Roofing hub.
Frequently asked questions
Are asphalt shingles fiberglass?
Most modern asphalt shingles are fiberglass shingles. A fiberglass shingle is an asphalt shingle built on a glass-fiber mat rather than an organic felt mat. Since organic-mat shingles were largely discontinued and their ASTM D225 standard was withdrawn in 2012, nearly every asphalt shingle sold new in North America today uses a fiberglass mat.
What is the difference between asphalt and fiberglass shingles?
There is usually no meaningful difference, because a fiberglass shingle is a type of asphalt shingle. The real comparison is between the two mats inside asphalt shingles: fiberglass mat versus organic felt mat. Fiberglass mats are lighter, resist fire and moisture better, and have replaced organic mats across the market.
Which is better, fiberglass or organic shingles?
Fiberglass is better for most homes and is what you can actually buy today. Fiberglass mats reach a Class A fire rating, resist moisture, and weigh less. Organic mats offered more cold-weather flexibility and tear toughness, which is why they lasted longest in northern climates, but they were discontinued because of moisture and fire drawbacks.
Why were organic shingles discontinued?
Organic-mat shingles were phased out mainly because the cellulose felt core absorbed moisture, leading to curling and blistering, and because it typically rated only Class C for fire versus Class A for fiberglass. ASTM withdrew the organic shingle standard, D225, in 2012 after North American production had effectively stopped.
Do fiberglass shingles cost more than organic shingles?
The cost comparison is now academic since organic shingles are effectively unavailable new. Historically, fiberglass shingles were priced competitively and often cost less to ship because they weigh less. Today, price differences you see between shingles come from grade (3-tab, architectural, designer) and brand, not from the mat, since the mat is fiberglass either way.
How can I tell if my roof has fiberglass or organic shingles?
Check the install date and a torn edge. Roofs installed after about 2010 are fiberglass. On a cut or damaged shingle, fiberglass shows fine white glass strands, while organic shows a brown, paper-like felt. Fiberglass also feels lighter and more rigid. Product paperwork citing ASTM D3462 confirms fiberglass; D225 indicates organic.
Reviewed by The Roofing Brief Team. Last reviewed July 2026.