Algae-Resistant Shingles: Copper Granule Specs and Warranty Terms by Brand

A shingle algae resistance warranty does not promise your roof stays clean. It promises a specific, capped payment if blue-green algae (Gloeocapsa magma) stains a shingle the manufacturer labeled algae resistant, and every major brand writes that promise differently. Terms in the current 2026 warranty documents run from 10 years to lifetime, the remedy is sometimes cleaning labor only, and on four of the seven brands below the headline number collapses if the roofer used the wrong hip and ridge cap.

Here is what the primary warranty documents actually say, pulled from the current published PDFs for GAF, Owens Corning, CertainTeed, IKO, Atlas, TAMKO and Malarkey, plus the granule specification that sits underneath all of it.

By The Roofing Brief Team. Last reviewed: August 2026.

What a shingle algae resistance warranty actually pays for

Every algae warranty in this comparison covers one organism and one symptom: discoloration from blue-green algae, the cyanobacterium Gloeocapsa magma. None of them cover moss, lichen, mold, mildew or green algae. The remedy is money toward cleaning or replacing the stained shingles, never a full roof replacement, and it is capped well below what a reroof costs.

The distinction that matters is the non-prorated period. That is the window when the manufacturer pays the full stated remedy. After it closes, the payment shrinks every month against a formula, and on most brands labor stops being covered at the same moment. A 25 year algae warranty with a 1 year non-prorated period is a very different product from a 25 year warranty with a 10 year one.

Algae coverage is also parasitic on the main warranty. CertainTeed states outright that coverage under its Limited Algae-Resistant Warranty “is valid only if coverage under the Limited Warranty for manufacturing defects … has not expired, been terminated, or been voided.” Lose the base warranty to a ventilation problem and the algae coverage goes with it.

Algae warranty terms by brand

The table below compares the algae provisions in each manufacturer’s current published limited warranty. Terms are for the algae-resistant version of each product only. Non-AR shingles carry no algae coverage at all on any of these brands.

Brand and program	Algae term	Non-prorated period	Remedy type	Cap
GAF StainGuard Plus PRO (Timberline UHDZ)	30 years	10 years	Commercial cleaning cost, or replacement at GAF’s option	Lesser of original cost of affected shingles or cost to clean
GAF StainGuard Plus	25 years	10 years	Cleaning or replacement at GAF’s option	Same as above
GAF StainGuard (base)	10 years	1 year	Cleaning or replacement at GAF’s option	Same as above
CertainTeed AR, Lifetime Products A (Landmark PRO, Grand Manor, Presidential, Belmont, Highland Slate, NorthGate ClimateFlex)	30 years	15 years	Pay to clean or replace, at CertainTeed’s sole option	Prorated share of shingle cost after year 15
CertainTeed AR, Lifetime Products B (Landmark, Landmark ClimateFlex)	25 years	10 years	Clean or replace, sole option	Prorated after year 10
CertainTeed Patriot / Patriot XL	10 years max, regardless of hip and ridge	10 years	Clean or replace, sole option	No proration inside the 10 years
Owens Corning StreakGuard AR, with qualifying hip and ridge	25 years	10 years	Repair (defined as cleaning), replace or recover, including labor	Not to exceed cost of AR shingles plus cost of installation
Owens Corning AR, without qualifying hip and ridge	10 years	1 year	Same	Same, then material only
Atlas featuring Scotchgard Protector, single-family site-built detached	Lifetime (matches shingle warranty)	10 years Premium Protection	Clean, repair or replace including labor and tear-off in year 1 to 10; full cost to clean only afterward	Cleaning cost of affected shingles after year 10
Atlas featuring Scotchgard Protector, all other property types	25 years	10 years	Same	Same
Atlas “ARS” designated shingles	10 years	1 year	Clean or replace only affected shingles	Years 2 to 10 prorated, “excluding all installation costs”
Malarkey featuring Scotchgard Protector	Limited Lifetime	10 years (120 months)	Replacement cost of materials and installation in year 1 to 10; repair, replace or cleaning labor payment afterward	Prorated on months installed after month 120
Malarkey Vista AR	25 years	10 years	Same	Same
Malarkey Highlander AR	15 years	10 years	Same	Same
IKO AR (Dynasty, Cambridge, Nordic, Armourshake, Crowne Slate, Royal Estate)	120 months (10 years)	12 months	Year 1: cost to clean or replace. After year 1: a cleaning labor payment certificate only	$15 per Square (100 sq ft), prorated
IKO Marathon Plus AR	60 months (5 years)	12 months	Same	Same
IKO Cambridge Cool Colors	No algae coverage	n/a	n/a	n/a
TAMKO 120 Month Algae Cleaning Limited Warranty (whole line, including Elite Glass-Seal 3-tab)	120 months (10 years)	12 months	Cleaning labor money only, no replacement option at any point	$15 per 100 sq ft of affected area, prorated after month 12

Two things jump out of that table. First, the two brands that put a hard dollar figure on the page, IKO and TAMKO, chose the identical number: $15 per 100 square feet. That looks like an industry convention rather than a competitive position, and it is worth reading as a floor rather than a differentiator. Second, GAF’s base StainGuard tier and Owens Corning’s downgraded tier both give you a 1 year non-prorated window. Algae staining rarely becomes visible in year one, so on those tiers the practical value of the warranty is close to zero by the time you would notice a problem.

For how the same seven brands compare on wind, proration and price, see the 2026 shingle brand comparison report. This page stays on the algae document itself.

There is no ASTM standard for shingle algae resistance

No ASTM standard tests asphalt shingles for algae resistance. Every “algae resistant” claim on a shingle wrapper rests on manufacturer-proprietary test methods, long-term outdoor exposure decks, and in the case of 3M Scotchgard Protector a third-party check on granule composition. There is no published pass/fail performance threshold anyone can hold a brand to.

The standards commonly name-dropped in roofing marketing all measure something else:

• ASTM D3273-21 rates mold growth on interior coatings in an environmental chamber. The standard itself cautions that use of the method for evaluating exterior coating performance has not been validated.
• ASTM D4610-98(2021) is a guide to detecting and removing fungal defacement from paint, not a resistance test.
• ASTM D3274-09(2021) is a visual rating scale for fungal and algal defacement, written for paint films.
• ASTM D7897-26 is a laboratory soiling and weathering method used to estimate aged solar reflectance and thermal emittance, not algae performance.
• ASTM G21-15(2021)e1 covers fungi resistance of synthetic polymeric materials.
• ASTM D3462/D3462M-25, the asphalt shingle specification itself, places in-service performance outside its scope and does not address algae.

That absence explains why warranty language is where the real information sits. A brand cannot be compared on a test result that does not exist, so the enforceable claim is the contract: the term, the remedy, the cap and the exclusions.

How copper granules actually stop algae

Algae resistance works by leaching copper ions off the roof surface into dew and rainwater at a controlled rate, which suppresses cyanobacteria colonies before they can stain. The delivery system is a copper-bearing roofing granule blended in with the standard color granules, not a coating sprayed on the finished shingle.

3M, which still manufactures roofing granules as part of its Safety and Industrial business, describes its product as a “tough, dense, non-porous, weather and UV resistant, ceramic-coated rock” and identifies the active ingredient as cuprous oxide. The widely repeated claim that these granules are a porous ceramic is a secondary-source description, not 3M’s own.

The one hard specification anyone publishes is the blend ratio. Per 3M’s Scotchgard Protector FAQ, its research shows that “a minimum 10% blend of copper-containing granules, uniformly distributed across the shingle surface and the hip and ridge, helps prevent black streaks caused by algae,” and all shingles featuring Scotchgard Protector are “tested by a third-party laboratory to ensure they contain the minimum 10% of copper-containing granules.”

Read that carefully: the third-party test verifies how much copper granule is in the blend. It is a composition audit, not an algae performance test. That is the honest ceiling on what third-party verification means here.

The two durations 3M publishes do not match

3M’s Scotchgard Protector FAQ says the product “is designed to prevent black streaks on roofs for the life of the shingle.” 3M’s copper roofing granules marketing page says the granules protect “for up to 20 years.” Those are different promises for the same technology, and the 20 year figure is the more defensible one to plan around.

3M’s own patent record supports treating 20 years as a realistic ceiling rather than a floor. US Patent 5,356,664 (3M, granted 1994) reports results from a Houston, Texas atmospheric exposure deck run over 12 years, projecting roughly 23 years of algicidal action for a 30% blend at 40 lb per ton copper and about 18 years for a 20% blend at 60 lb per ton. The same patent notes algae infestation began while copper still remained in the granules, which means the failure mode is the rate at which copper releases, not running out of it. A later 3M patent, US 8,808,756 B2 (granted 2014), describes a proprietary Copper Extraction Test, again not an ASTM method.

Which brands use 3M granules, and which use their own

Per 3M’s published FAQ, Atlas Roofing and Malarkey Roofing each manufacture shingle products featuring Scotchgard Protector. Both, not one. That is worth stating plainly because “the only brand with 3M Scotchgard” is a common line in roofing marketing and in third-party roundups.

GAF uses its own system. Per GAF’s published technology page, its Time-Release Algae-Fighting Technology is “proprietary to GAF” and “engineered with thousands of copper microsites that release algae-fighting copper efficiently, over time,” with Timberline UHDZ carrying “10% MORE” of it than the StainGuard Plus tier. Owens Corning (StreakGuard), CertainTeed (AR), IKO and TAMKO likewise use their own copper-containing granule formulations rather than a licensed 3M program. GAF’s warranty document itself puts it vaguely, noting only that prevention “is achieved through formulations or through unique blends of granules.”

The hip and ridge condition that quietly cuts coverage

On four brands, the advertised algae term is conditional on installing that manufacturer’s algae-resistant hip and ridge cap. Miss it and coverage drops, in one case by 15 years and by 9 years of non-prorated protection at the same time. This is the single most common way a homeowner ends up with less algae coverage than the brochure said.

Brand	Required accessory	Penalty for skipping it
Owens Corning	DecoRidge, DuraRidge, ImpactRidge, ProEdge or RIZERidge	AR period drops from 25 years to 10, and the non-prorated period drops from 10 years to 1 year
CertainTeed	CertainTeed AR hip and ridge accessories	25 or 30 year coverage drops to 10 years from installation
Malarkey	EZ-Ridge or RidgeFlex featuring Scotchgard Protector	Algae protection warranties require it; both the Scotchgard and AR programs are conditioned on it
Atlas	StormMaster Hip and Ridge, Pro-Cut High Profile Hip and Ridge, or Pro-Cut Hip and Ridge, each featuring Scotchgard Protector	Shingles do not qualify for the Scotchgard algae warranty
IKO	Marathon Plus AR, IKO UltraHP, UltraHP IR, Hip & Ridge 12, Hip & Ridge Class 4, or an IKO-approved equivalent	Condition applies across the whole algae warranty table
GAF	None stated for the shingle term, but ridge cap and starter strip carry their own StainGuard terms and must bear the logo to be covered	Unlabeled accessories are simply outside the algae warranty

The mechanism behind the condition is sound: the ridge is the highest point on the roof, so copper leaching from a non-AR cap contributes nothing and the cap itself streaks. 3M’s blend guidance specifically calls for uniform distribution “across the shingle surface and the hip and ridge.” The commercial effect is that a $200 accessory decision can be worth 15 years of coverage.

Paying more does not always buy more algae coverage

Two findings in the current documents cut against the assumption that upgrading buys better algae protection. IKO’s ROOFPRO contractor-certification warranties list the algae term as 10 years in every ROOFPRO column, with the footnote “Same as standard warranty.” The enhanced warranty extends other coverages and leaves algae untouched.

The other is IKO’s Cambridge Cool Colors, which shows “N/A” in the algae resistance column of the current 12/25 print of document MR1L032. The cool-roof variant of a shingle whose standard version carries 120 months of algae coverage has none. Buyers optimizing for solar reflectance should check the algae column separately rather than assuming it carries across the color family.

Revision dates matter here. An earlier 02/25 print of the same IKO document code showed Dynasty Cool Colors Plus as N/A and carried a footnote limiting Cambridge Cool Colors algae coverage to one color. The current 12/25 print, effective for shingles installed on or after February 1, 2026, removed both. Ask which revision governs your installation date before relying on any figure.

What voids, excludes or shrinks algae coverage

The exclusions do more work than the terms. Five stand out across the current documents, and three of them are specific enough that most homeowners and plenty of contractors never see them coming.

1. TAMKO’s territory exclusion. TAMKO’s remedies “APPLY ONLY TO SHINGLES INSTALLED IN THE FORTY-EIGHT CONTIGUOUS UNITED STATES AND CANADA (EXCLUDING QUEBEC AND NEW BRUNSWICK).” Outside that footprint the shingles are, in TAMKO’s words, “SOLD ‘AS IS’ AND WITHOUT WARRANTY OF ANY KIND.” Alaska, Hawaii, US territories, Quebec and New Brunswick get no algae warranty at all.
2. Atlas requires the whole roof. Atlas excludes claims where its Scotchgard shingles “do not comprise the entire shingled area of the roof, including, without limitation, hip and ridge shingles,” and also where non-Atlas Scotchgard shingles shed water onto Atlas Scotchgard shingles. Partial reroofs and mansard or low-slope tie-ins can fall outside coverage. Atlas separately excludes slopes of 2:12 or less.
3. Cashing the cheque may end everything. TAMKO’s document states that “ACCEPTANCE OF PAYMENT … SHALL IMMEDIATELY TERMINATE ALL OBLIGATIONS,” which on its face means accepting a cleaning payment closes out the broader warranty as well. Read the settlement letter before depositing it.
4. Claims cost the owner money and material. TAMKO may require a completed questionnaire, photographs and two shingle samples, at the owner’s expense, and states that refusal terminates the warranty. Pulling samples off a sealed roof is destructive work.
5. Only one organism counts. Every brand here excludes moss, lichen, mold, mildew and green algae. Only blue-green algae staining is covered. A roof with visible moss growth on the north face has no claim, and the difference between algae streaking and other growth determines whether there is a claim at all.

Copper granules and aluminum gutters

CertainTeed, Owens Corning and Atlas all publish the same warning, and all three disclaim liability for it: in low-volume rain areas and salt fog areas, copper released by algae-resistant granules can react with aluminum gutters and cause severe corrosion. CertainTeed defines low-volume rain as areas receiving insignificant rainfall over a 90 day period and names parts of the Southern California coastline as a salt fog example. All three recommend vinyl or copper gutters instead of aluminum with AR shingles.

This is a real cost consideration in dry and coastal-arid markets, because it converts an algae upgrade into a gutter material decision. It is also one of the few places where the manufacturers agree with each other almost word for word.

How the proration math actually works

After the non-prorated period ends, the payment is reduced against the elapsed portion of the algae term. The brands split into two formula families, and one of the published formulas appears to be written backwards.

TAMKO prorates on months remaining. Its own worked example: with 40 months remaining on a 120 month term, the multiplier is one third, so the $15 per 100 sq ft rate becomes $5 per 100 sq ft. That is the intuitive direction.

Owens Corning prorates on years elapsed. Its worked example: a claim in the 16th year of a 25 year AR term is reduced by 16/25ths of the purchase cost of the affected AR shingles. Labor is not covered at all during the prorated period.

GAF uses the same elapsed-time direction, calculating “the amount of use” by dividing months elapsed since installation by the number of months in the algae warranty term, and reducing its contribution accordingly.

IKO’s printed formula reads differently. The document describes the payment as prorated by the “months that the Shingles have been installed … divided by the maximum period of coverage.” Taken literally, that multiplier grows as the roof ages, which would mean a larger payment the longer you wait. TAMKO’s formula is the inverse. This looks like a drafting error rather than a genuinely generous term, and how IKO administers it in practice is not something the public document establishes. Anyone filing an IKO algae claim should ask the warranty department to state the calculation in writing.

How to check an algae warranty before you sign the contract

The algae column on a brochure is not the contract. Work through these six steps against the actual limited warranty PDF for the product and revision date on your proposal, and the real coverage becomes clear in about ten minutes.

1. Confirm the shingle is the AR version. Algae coverage attaches to the algae-resistant SKU only, and on GAF specifically to packages bearing the StainGuard, StainGuard Plus or StainGuard Plus PRO logo. A non-AR shingle in an AR color has no coverage.
2. Find the non-prorated period, not the headline term. This is the number that determines what a claim is worth. Compare 10 years against 1 year before comparing 25 years against 30.
3. Check the hip and ridge requirement and get the specified cap named in the contract. Write the exact accessory into the scope of work, because this is where the 25 to 10 year downgrades happen.
4. Read the remedy sentence. Decide whether you are being sold cleaning labor money (TAMKO, IKO after year 1) or a cleaning-or-replacement option at the manufacturer’s discretion (GAF, CertainTeed, Owens Corning, Malarkey, Atlas).
5. Check the geographic and property-type limits. TAMKO excludes Alaska, Hawaii, US territories, Quebec and New Brunswick. Atlas limits lifetime algae coverage to single-family site-built detached residences and drops everything else to 25 years. Owens Corning and CertainTeed reduce terms on non-residential ownership.
6. Match the revision date to your installation date. Warranty documents are revised on their own schedule, and terms move. Ask the supplier for the revision that governs the date your shingles are installed.

If your roof already has streaking, the warranty question and the cleaning question are separate decisions. Roof washing cost runs well under the deductible-level numbers people expect, which is often why a prorated $5 per 100 sq ft certificate is not worth the claim paperwork. Whether algae is likely on your roof in the first place is largely a climate question, and where Gloeocapsa magma hits roofs hardest tracks how long roof surfaces stay damp rather than how hot or humid the region feels.

Is the algae warranty worth paying for?

The algae upgrade is usually worth buying for the granules, not for the warranty. Copper granules genuinely delay staining, with 3M’s own exposure-deck data pointing to roughly 18 to 23 years of algicidal action depending on blend and copper loading. The warranty behind it pays a capped, prorated cleaning allowance that in many cases is smaller than the cost of filing.

The exception is the front end. During a 10 year non-prorated period on Owens Corning, Atlas, Malarkey, CertainTeed’s B tier or GAF’s Plus tiers, a valid claim can cover cleaning labor and in some cases replacement. That is real coverage, and it is precisely the window that shrinks to 1 year if the specified hip and ridge cap is left off the job. Getting the accessory right is the highest-value decision in this entire comparison, and it costs a fraction of the shingle upgrade. Brands like Malarkey that tie the algae program to a named ridge product make the requirement easy to verify on a proposal.

Frequently asked questions

How long is the algae warranty on shingles?

Algae warranty terms in the current 2026 manufacturer documents run from 10 years to lifetime. IKO and TAMKO cap most products at 120 months. GAF runs 10, 25 or 30 years by StainGuard tier. CertainTeed runs 10, 25 or 30 years by product. Owens Corning runs 25 years with a qualifying hip and ridge cap or 10 without. Atlas and Malarkey offer lifetime terms on their Scotchgard Protector products.

Is there an ASTM standard for algae resistant shingles?

No. No ASTM standard tests asphalt shingles for algae resistance. ASTM D3273 covers interior coatings in a chamber, D4610 and D3274 address paint defacement, D7897 measures soiling for solar reflectance, and G21 covers fungi on synthetic polymers. ASTM D3462, the asphalt shingle specification, places in-service performance outside its scope. Algae claims rest on proprietary methods and outdoor exposure decks.

What voids an algae resistance warranty?

The common triggers are installing a non-algae-resistant hip and ridge cap, which cuts terms sharply on Owens Corning, CertainTeed, Malarkey, Atlas and IKO, and losing the underlying manufacturing-defect warranty, which CertainTeed states also voids algae coverage. TAMKO excludes shingles installed outside the 48 contiguous states and Canada excluding Quebec and New Brunswick. Atlas excludes roofs where its Scotchgard shingles are not the entire shingled area.

How much do algae warranties actually pay?

IKO and TAMKO both cap payment at $15 per 100 square feet of affected area, prorated after the first year. GAF caps its contribution at the lesser of the original cost of the affected shingles or the cost to clean them. Owens Corning caps at the cost of the AR shingles plus installation during the non-prorated period, then material only. None of them fund a roof replacement.

Do algae resistant shingles damage aluminum gutters?

CertainTeed, Owens Corning and Atlas all warn that in low-volume rain areas and salt fog areas, copper released by algae-resistant granules can react with aluminum gutters and cause severe corrosion. All three recommend vinyl or copper gutters instead and disclaim liability for aluminum gutter damage. CertainTeed defines low-volume rain as insignificant rainfall over a 90 day period.

Do algae warranties cover moss and lichen?

No. Every major brand’s algae warranty covers only discoloration from blue-green algae, the cyanobacterium Gloeocapsa magma. Malarkey excludes “all other forms of algae, mold, mildew, lichens, moss.” Owens Corning excludes mold, lichen and green algae. TAMKO excludes moss and fungus outright. Green staining, moss cushions and lichen crusts fall outside coverage on every document reviewed here.

Does a contractor certification upgrade extend algae coverage?

Not on IKO. Every ROOFPRO column in IKO’s current warranty table lists the algae resistance term as 10 years with the footnote “Same as standard warranty,” so the enhanced contractor warranty extends other coverages while leaving algae unchanged. Enhanced warranties on other brands typically extend the non-prorated period for manufacturing defects rather than the algae term. Check the algae column specifically.

Which shingle brands use 3M Scotchgard Protector granules?

Per 3M’s published Scotchgard Protector FAQ, Atlas Roofing and Malarkey Roofing each manufacture shingle products featuring Scotchgard Protector. GAF uses its own Time-Release Algae-Fighting Technology with copper microsites. Owens Corning StreakGuard, CertainTeed AR, IKO and TAMKO use their own copper-containing granule formulations rather than a licensed 3M program.

Sources: GAF Shingle and Accessory Limited Warranty; CertainTeed Limited Warranty (2026 printing); Owens Corning Limited Lifetime Warranty; IKO Limited Warranty document MR1L032 (12/25 printing) and ROOFPRO warranty tables; Atlas Limited Warranty; TAMKO Fiberglass Asphalt Shingle Limited Warranty document 41001460 (Rev. 03/16/2026); Malarkey Limited Warranty; 3M Scotchgard Protector FAQ and 3M copper roofing granules product page; US Patents 5,356,664 and 8,808,756 B2; ASTM D3273-21, D3274-09(2021), D4610-98(2021), D7897-26, G21-15(2021)e1, D3462/D3462M-25.