By The Roofing Brief Team. Last reviewed: October 2026.
Duro-Last roofing is a custom-fabricated PVC single-ply system sold by a Saginaw, Michigan, company since 1978, and owned since June 23, 2025 by Amrize, the North American company Holcim spun off two years after buying Duro-Last for $1.293 billion. The flagship membrane comes in 40, 50 and 60 mil, with 28 mil of PVC above the scrim on the 50 and 60 mil sheets, and the factory welds up to 85% of the seams before the roof ships, per Duro-Last’s membrane page.
Every number on this page comes from Duro-Last, Carlisle or Sika data sheets, Duro-Last warranty forms and requirement sheets revised between 2018 and December 2025, court records, Holcim releases, BLS price data or a public 2009 state price schedule. Contractor blogs that rank for “Duro-Last roofing” are quoted only where they publish a price, and each one is labeled as a contractor claim.
Duro-Last roofing key numbers at a glance
The figures below answer the questions owners and specifiers ask first about Duro-Last roofing: thickness, top-layer thickness, warranty length, custom panel size and ownership. Values are typical published values from the dated maker documents named in the Source column, not a guarantee for a specific building.
| Item | Figure | Source |
|---|---|---|
| Membrane families | PVC (Duro-Last, Duro-Last X, Duro-Tuff, Duro-Fleece), KEE-PVC (Duro-Last EV), TPO (Duro-TECH, launched 2025) | duro-last.com product pages, October 2026 |
| Flagship thickness | 40, 50 or 60 mil; PVC above scrim 17, 28 and 28 mil | Duro-Last 40, 50 and 60 mil data sheets, rev. Aug. to Oct. 2025 |
| Product standard | ASTM D4434 (PVC); 50 mil classed Type III, 40 mil Type IV | Duro-Last 50 and 40 mil data sheets |
| Largest custom deck sheet | 2,500 sq ft (40 mil), 2,000 sq ft (50 mil), 1,500 sq ft (60 mil) | Duro-Last 2-Minute Fact Sheet, rev. 3.24.25 |
| Warranty terms | 15 to 25 year NDL on the flagship; 30 year NDL needs 80 mil roll goods | Duro-Last 25 and 30-Year Warranty Requirements, rev. 03/07/2024 |
| Consequential damage cap | Up to $2,000,000 of leak-related interior damage (Supreme 15-year form) | Duro-Last sample Supreme warranty DL280016, 06.04.2025 |
| Owner | Amrize Building Envelope LLC (Amrize, NYSE: AMRZ) | Duro-Last data sheets; Holcim release, June 2025 |
Is Duro-Last roofing good? What the data sheets show
On its own published test results, Duro-Last’s flagship PVC passes every ASTM D4434 requirement with margin: the 50 mil sheet reports 438 x 390 lbf/in breaking strength against a 200 lbf/in minimum and 28 mil above the scrim against a 16 mil minimum. Those are maker-reported typical values, so the real test of a given roof is the installer and the warranty paperwork.
The table compares the three flagship thicknesses with the ASTM D4434 requirement printed on each Duro-Last data sheet. Machine-direction results are listed first, as Duro-Last prints them.
| Property (test method) | DL40 | DL50 | DL60 | ASTM D4434 requirement printed on the sheet |
|---|---|---|---|---|
| ASTM D4434 class | Type IV | Type III (also meets II and IV) | Type III with fabric backing (also meets II) | n/a |
| Thickness over scrim (D7635) | 17 mil | 28 mil | 28 mil | 16 mil minimum |
| Breaking strength (D751 grab) | 441 x 355 lbf/in | 438 x 390 lbf/in | 438 x 390 lbf/in | 275 (Type IV) or 200 (Type III) lbf/in |
| Elongation | 28% x 31% | 31% x 31% | 31% x 31% | 25% (Type IV) or 15% (Type III) |
| Tear strength (D751 Proc. B) | 125 x 136 lbf | 132 x 163 lbf | 132 x 163 lbf | 90 (Type IV) or 45 (Type III) lbf |
| Seam strength | 360 lbf | 417 lbf | 431 lbf | 75% of breaking strength |
| Water absorption, 168 h at 158°F (D570) | 2.6% | 1.7% | 2.6% | 3% maximum |
| Low-temperature bend (D2136) | Pass at -40°F | Pass at -40°F | Pass at -40°F | Pass at -40°F |
| Weight | 0.22 lb/sq ft | 0.29 lb/sq ft | 0.36 lb/sq ft | n/a |
| Data sheet revision | 10/16/2025 | 08/28/2025 | 10/14/2025 | n/a |
Source: Duro-Last 40 mil, 50 mil and 60 mil product data sheets. Each sheet lists UL Evaluation Report ER10128, FM Approvals, CCMC 13299-L, State of Florida, Miami-Dade County and Texas Department of Insurance among its codes and approvals.
White Duro-Last carries Cool Roof Rating Council product ID 0610-0001a: initial solar reflectance 0.86, 3-year aged 0.69 on the 50 and 60 mil sheets (0.74 on 40 mil), thermal emittance 0.89, and an initial SRI of 108 to 109 that ages to 85 on the 50 mil sheet. Tan (0610-0005), gray (0610-0004) and dark gray (0610-0006) age to SRI values of 35, 45 and 23 to 25, so only white earns the LEED heat-island credit the data sheets mention.
Duro-Last product lines and membrane specs
The main Duro-Last membrane lines in 2026 are the custom-fabricated flagship, five roll-good families and the Duro-Life 600 system built with DuPont; fleece-backed versions (Duro-Fleece Plus, EV Fleece, Duro-TECH Fleece TPO), Duro-Shield coatings and Defendex metal panels fill out the catalog. Only the flagship ships as factory-welded deck sheets, and Duro-Last makes custom-fabricated flashings for every membrane family.
| Line (year introduced) | Polymer and standard | Thickness | Above scrim | Weight (lb/sq ft) | Scrim (threads/in) | Format and colors |
|---|---|---|---|---|---|---|
| Duro-Last (1978) | PVC, ASTM D4434 | 40 / 50 / 60 mil | 17 / 28 / 28 mil | 0.22 / 0.29 / 0.36 | 18 x 14 weft-inserted | Custom deck sheets or rolls; white, tan, gray, dark gray, terra cotta (50 mil only) |
| Duro-Last X, DLX (2021) | PVC, ASTM D4434 | 50 / 60 / 80 mil | 28 / 28 / 38 mil | 0.31 / 0.36 / 0.46 | 18 x 14 | Rolls up to 10 ft wide, custom-cut to 200 ft (50, 60 mil) or 130 ft (80 mil); matte white |
| Duro-Tuff (2012) | PVC | 50 / 60 / 80 mil | 26 / 31 / 41 mil | 0.28 / 0.35 / 0.51 | 18 x 9 | Rolls up to 10 ft x 100 ft; 12 colors including patina, copper and colonial red |
| Duro-Fleece | PVC, fleece-backed | 50 / 60 / 80 mil (68 / 78 / 98 mil with fleece) | 26 / 31 / 41 mil | 0.33 / 0.39 / 0.53 | 18 x 9 | 5 or 10 ft rolls with one 3 in fleece-free selvage; 12 colors |
| Duro-Last EV | PVC with Dow Elvaloy KEE; ASTM D4434-12 and D6754-10 | 50 / 60 / 80 mil | 25 / 28 / 38 mil | 0.28 / 0.30 / 0.51 | 18 x 9 | Rolls; white only; not compatible with Duro-Last, Duro-Tuff or Duro-Fleece accessories |
| Duro-TECH TPO (2025) | TPO, ASTM D6878 | 45 / 60 / 80 mil | 21 / 30 / 37 mil | 0.23 / 0.31 / 0.42 | 9 x 9 | Rolls; white top, gray bottom; no seam sealant required per Duro-Last |
| Duro-Life 600 (2022) | System: DL60 or DLX 60/80 over DuPont Styrofoam XPS | 60 or 80 mil membrane | 28 or 38 mil | n/a | 18 x 14 | 25 or 30 year membrane warranty; 50 year XPS re-use and thermal warranty from DuPont |
Source: Duro-Last product pages for Duro-Last X, Duro-Tuff, Duro-Fleece, Duro-Last EV, Duro-TECH TPO and Duro-Life 600, checked October 2026; Duro-TECH TPO 60 mil data sheet rev. 12/05/2025; introduction years from the Duro-Last history timeline.
Why the 60 mil flagship has the same top layer as the 50 mil
The 60 mil Duro-Last sheet adds 10 mil of thickness below the scrim, not above it: both the 50 and 60 mil data sheets list 28 mil of PVC over the scrim. The 60 mil sheet is 0.07 lb/sq ft heavier and unlocks the 25-year warranty, but its weathering layer is no thicker. Buyers who want more PVC above the scrim have to move to an 80 mil roll good, such as DLX80 at 38 mil or Duro-Tuff 80 at 41 mil.
The custom-fabricated sheet sizes also shrink as thickness rises: 2,500 sq ft and 100 ft maximum in 40 mil, 2,000 sq ft and 80 ft in 50 mil, and 1,500 sq ft and 60 ft in 60 mil, with 60 mil sheets limited to 24 ft lengths on a 25 ft carpet roll. A 20,000 sq ft roof therefore needs at least 10 deck sheets in 50 mil and at least 14 in 60 mil.
Thickness over scrim: Duro-Last vs Carlisle and Sika
Thickness over scrim, measured by ASTM D7635, is the PVC layer exposed to weather; ASTM D4434 requires at least 16 mil. Several contractor reviews say Duro-Last has “the thickest membrane above scrim layer in the industry.” The data sheets show Duro-Last ahead by 1 to 6 mil at 50 and 60 mil; at 80 mil, Duro-Tuff’s 41 mil edges Sika’s 40 mil while DLX80’s 38 mil trails it.
| Membrane | 50 mil | 60 mil | 80 mil | Source and date |
|---|---|---|---|---|
| Duro-Last flagship PVC | 28 mil | 28 mil | Not made | Duro-Last data sheets, 2025 |
| Duro-Last X PVC | 28 mil | 28 mil | 38 mil | DLX 80 mil data sheet rev. 10/14/2025; DLX page |
| Duro-Tuff PVC | 26 mil | 31 mil | 41 mil | Duro-Tuff product page, October 2026 |
| Carlisle Sure-Flex PVC | 22 mil | 27 mil | 37 mil | Sure-Flex PVC data sheet, 10.10.25 |
| Sika Sarnafil G410 | n/a | 27 mil | 40 mil | G410-60 data sheet (Nov. 2023); G410-80 EnergySmart (Sept. 2022) |
| Duro-TECH TPO (for reference) | 45 mil: 21 mil | 30 mil | 37 mil | Duro-TECH TPO page and 60 mil data sheet |
| ASTM D4434 minimum | 16 mil | 16 mil | 16 mil | Printed on each data sheet |
Two caveats apply to that comparison. Sika lists G410 overall thickness as a minimum while Duro-Last and Carlisle list nominal or typical values, and Sika’s data sheet names an integral fiberglass mat as G410’s reinforcement where Duro-Last and Carlisle use polyester scrims, so the sheets are not built identically. A 1 to 6 mil difference in top layer is a real but modest gap; seam quality and warranty terms move service life more than 3 mil of PVC.
How custom fabrication changes the Duro-Last seam count
Duro-Last’s own comparison sheet models a 50,000 sq ft roof and counts 1,278 linear feet of field seams for its custom-fabricated system, against 5,130 LF with 10 ft roll goods and 7,968 LF with 6 ft rolls. Those are the maker’s figures from its Field Seam Overlay sell sheet (updated 9.27.18), not an independent count.
| System on the 50,000 sq ft example roof | Field seams (LF) | Field seams per 1,000 sq ft | Duro-Last’s field seams as a share |
|---|---|---|---|
| Duro-Last custom-fabricated, 5 ft laps | 1,278 | 25.6 | 100% |
| 10 ft wide roll goods | 5,130 | 102.6 | 25% (75% fewer field seams) |
| 6 ft wide roll goods | 7,968 | 159.4 | 16% (84% fewer field seams) |
Arithmetic: field seams divided by 50 (thousands of sq ft); share equals 1,278 divided by the roll-good figure. Roofing Brief calculation from Duro-Last’s sheet.
The worked example applies the deck-sheet limits and data-sheet weights to a 20,000 sq ft low-slope roof. It shows how thickness choice changes the number of factory-welded panels a crew unfolds and the dead load added to the deck.
| Input or result | DL50 | DL60 | Arithmetic |
|---|---|---|---|
| Roof area | 20,000 sq ft | 20,000 sq ft | Given |
| Largest deck sheet | 2,000 sq ft | 1,500 sq ft | 2-Minute Fact Sheet |
| Minimum deck sheets | 10 | 14 | 20,000 / 2,000; 20,000 / 1,500 = 13.3, rounded up |
| Membrane weight | 5,800 lb | 7,200 lb | 20,000 x 0.29; 20,000 x 0.36 |
| Added dead load | 0.29 psf | 0.36 psf | Data sheet weight per sq ft |
| Longest warranty available | 20 year NDL | 25 year NDL | Data sheet warranty tables |
Duro-Last warranties: which membrane qualifies for which term
Duro-Last sells four warranty families, Supreme, Ultra, Basic and Residential, and the term available depends on membrane thickness: 15 years on 40 mil, up to 20 on 50 mil, up to 25 on 60 mil and up to 30 only on 80 mil roll goods. Only Supreme includes consequential damages; every Ultra, Basic and Residential form carries a footnote excluding them.
| Warranty family | DL40 | DL50 | DL60 | DLX80 | Consequential damages |
|---|---|---|---|---|---|
| Supreme | 15 yr NDL | 15 yr NDL; 20 yr NDL (15 yr consequential + 5 yr material, or + 5 yr material and labor) | Same as DL50 | Same as DL50 | Yes, for 15 years |
| Ultra | 15 yr high wind | 15 yr hail; 15 yr hail and high wind; 15 and 20 yr high wind | Adds 25 yr high wind | 15 yr hail; 15 yr hail and high wind; 15, 20 and 25 yr high wind | No |
| Basic | 15 yr NDL | 15 or 20 yr NDL | 15, 20 or 25 yr NDL | 15, 20, 25 or 30 yr NDL | No |
| Residential | 15 yr material limited | 15 or 20 yr material limited | 15 or 20 yr material limited | 15 or 20 yr material limited | No |
Source: warranty tables on the Duro-Last 40, 50 and 60 mil and DLX 80 mil product data sheets (revised 2025) and the Duro-Last warranties page, checked October 2026.
What the 2025 sample warranty forms actually say
Duro-Last’s sample warranty forms dated 06.04.2025 are issued by Amrize Building Envelope LLC and set deadlines and exclusions that contractor reviews skip. The Supreme form gives an owner 72 hours to report a leak, while the FAQ and the Protecting Your Investment booklet say 7 to 14 days depending on the warranty. The issued form governs, so read the notice clause first.
| Term | Supreme 15 yr NDL (DL280016) | Basic 15 yr NDL (DL280010) | Ultra 20 yr High Wind (DL280015) |
|---|---|---|---|
| Leak notice deadline | 72 hours from discovery | 14 days | 14 days, including any wind event over 72 mph (3 second gust at 33 ft) |
| Wind exclusion | Winds over 54 mph, 3 second gust at 10 m | Winds over 54 mph | Blank speed filled in per project |
| Hail | Excluded | Excluded | Excluded (hail needs an Ultra hail form) |
| Interior damage | Covered up to $2,000,000 when caused by a system defect or installer workmanship | Excluded | Excluded |
| Transfer | Duro-Last’s written consent; pre-transfer inspection possible | No transfer clause in the sample form | $500 transfer fee plus any non-warranted repairs found |
| Uncovered leak call | Owner pays Duro-Last’s direct inspection expenses | Not in the form; the owner booklet says such investigations are invoiced | Not in the form; same booklet rule |
| Disputes | Mediation, then state or federal court, in Davidson County, Tennessee | Same | Same |
Source: Duro-Last sample warranties downloaded from the Duro-Last specifications library, October 2026. Owner care rules come from the Protecting Your Investment booklet: at least two inspections a year, sealants bought from Duro-Last, power washing no higher than 1,000 psi with a wide tip held 12 in from the membrane, and no solvent cleaners.
Duro-Last 25 and 30-year warranty requirements
The two longest Duro-Last warranties are Basic or Ultra high-wind forms with no consequential or hail coverage, and they add installation rules beyond the standard specification. The custom-fabricated flagship qualifies for 25 years at 60 mil but is listed “N/A” for 30 years, which requires 80 mil DLX, Duro-Tuff, Duro-Fleece, Duro-Fleece Plus, EV or EV Fleece.
| Requirement | 25 year NDL | 30 year NDL |
|---|---|---|
| Minimum field membrane | 60 mil | 80 mil |
| Flagship custom-fab Duro-Last | Allowed | Not available |
| Parapets / flashings / T-lap patches | 60 / 50 / 40 mil minimum | 60 / 50 / 40 mil minimum |
| Wood deck for mechanically fastened | 5/8 in plywood or 1 in plank minimum | Same |
| Fastener pull test | 250 lb or greater | 250 lb or greater |
| Adhered system test | 150 lb per sq ft (1 ft x 1 ft tester) or 600 lb (2 ft x 2 ft) | Same |
| Insulation, when code requires it | At least 2 layers, joints staggered 6 in minimum | Same |
| Edge metal | Bought from Exceptional Metals or Duro-Last | Same |
| Consequential damages / hail | No / No | No / No |
| Transfer | Inspection and fee | Inspection and fee |
Source: Duro-Last 25 and 30-Year Warranty Requirements, revised 03/07/2024. Hail coverage has its own Hail Warranty Requirements sheet (rev. 10/19/2023): hail up to 1 inch, a 15-year maximum, 50 mil or thicker membrane, a 1/4 in Duro-Guard cover board or at least 1-1/2 in Duro-Guard ISO on top, and insulation, cover board and adhesives all bought from Duro-Last.
How much does a Duro-Last roof cost?
Expect roughly $9 to $14 per sq ft installed for a new PVC roof in 2026, the range in The Roofing Brief’s 2026 roofing cost report; a mechanically fastened Duro-Last recover with no tear-off can land lower. Duro-Last does not publish installed prices. Its FAQ says cost depends on the building’s condition and materials and sends buyers to a sales representative.
| Price point | Figure | What it includes | Source and date |
|---|---|---|---|
| PVC single-ply installed, national | $9 to $14 per sq ft | New PVC roof, all brands | Roofing Brief 2026 cost report |
| Duro-Last 50 mil recover, metal or wood deck, under 100,000 sq ft | $4.21 per sq ft (2009); about $6.65 in Sept. 2026 dollars | Mechanically fastened, no tear-off, recovery board, up to 25 penetrations, 4 walkpads | Ohio STS contract 7756400506, effective April 1, 2009; CPI-U adjustment by Roofing Brief |
| Duro-Last membrane, material only | $0.83 (40 mil) and $0.93 (50 mil) per sq ft list in 2009; about $1.31 and $1.47 today | White, gray or tan membrane, no tabs | Duro-Last GSA price list GS-07F-5689P, effective 3/29/2009 |
| Duro-Last overlay of an existing flat roof | $3 to $5 per sq ft | Contractor claim, undated | Sentry Roofing blog, checked October 2026 |
| Duro-Last metal roof retrofit | $2.75 to $5.00 per sq ft | Contractor claim, undated | Sentry Roofing and Exterior Pro blogs |
| Government or prevailing-wage project | $6 to $12 per sq ft | Contractor claim, undated | Exterior Pro blog, checked October 2026 |
CPI adjustment: BLS CPI-U was 213.240 in April 2009 and 336.940 in September 2026, a factor of 1.580. General inflation understates roofing cost growth, so treat the adjusted 2009 contract rates as a floor rather than a quote.
Is there a Duro-Last price list?
Duro-Last’s current price list is not public: its warranty requirement sheets point contractors to “the Duro-Last Price List under Sales/Price Lists on the Duro-Last Portal.” The most detailed public Duro-Last schedule found is a 2009 GSA and Ohio STS price list that priced membrane, accessories and installed line items for public buyers. Public agencies today buy through Duro-Last’s job order contract with TIPS-USA, a cooperative that Duro-Last says serves more than 90,000 schools, cities and nonprofits.
Worked example: Duro-Last cost on a 20,000 sq ft warehouse
The table builds a 20,000 sq ft, single-story warehouse estimate from the 2009 Ohio STS line items, each multiplied by the 1.580 CPI-U factor. It is a Roofing Brief estimate to show which choices move the price, not a bid.
| Line | 2009 rate | 2026 dollars | On 20,000 sq ft |
|---|---|---|---|
| Base: 50 mil, mechanically fastened recover, metal deck | $4.21/sq ft | $6.65/sq ft | $133,000 |
| Add: tear off a 2 in thick existing roof ($1.21 per inch) | $2.42/sq ft | $3.82/sq ft | $76,400 |
| Add: fully adhered instead of mechanically fastened | $0.68/sq ft | $1.07/sq ft | $21,400 |
| Total, tear-off and adhered | $7.31/sq ft | $11.54/sq ft | $230,800 |
| Cross-check: 2026 PVC range | n/a | $9 to $14/sq ft | $180,000 to $280,000 |
What moves a Duro-Last price, and by how much
The same April 1, 2009 Ohio STS schedule priced 17 installation adders (items C.1 to C.17) per sq ft, linear foot or unit, which makes it one of the few public sources that puts a dollar figure on each Duro-Last cost driver. Insulation, cover board and decking were priced as further extras.
| Cost driver (roofs under 100,000 sq ft) | 2009 adder | About in 2026 dollars |
|---|---|---|
| Concrete deck instead of metal or wood (50 mil base $5.53 vs $4.21) | $1.32/sq ft | $2.09/sq ft |
| 60 mil instead of 50 mil ($4.47 vs $4.21) | $0.26/sq ft | $0.41/sq ft |
| Building over 40 ft high | $1.21/sq ft | $1.91/sq ft |
| Pitched roof steeper than 4:12 | $1.47/sq ft | $2.32/sq ft |
| Asphalt-resistant product over an asphalt roof | $0.95/sq ft | $1.50/sq ft |
| Special project requirements | $3.16/sq ft | $4.99/sq ft |
How long does a Duro-Last roof last?
Duro-Last’s longest warranties run 25 years on 60 mil and 30 years on 80 mil roll goods, and its Duro-Life 600 system is marketed for 600 months, or 50 years, of roof and insulation performance. Duro-Last does not publish a single service-life figure for the flagship; its membrane page claims “more than four decades of proven performance,” dating from the first roof installed in 1978.
A warranty term is not a lifespan. The data sheets report accelerated aging under ASTM G155 for 10,000 hours and heat aging for 56 days at 176°F as passes, which says the sheet meets the standard, not how many years a roof lasts. Drainage, rooftop traffic and the 2-inspections-a-year schedule in Duro-Last’s booklet decide most real outcomes. Broader low-slope data are on our flat roof lifespan page.
Who owns Duro-Last roofing?
Amrize owns Duro-Last. Holcim agreed to buy Duro-Last on February 7, 2023 in a $1,293 million deal, closed it on April 3, 2023, and then spun off its North American business as Amrize, which began trading on the NYSE and SIX on June 23, 2025. Duro-Last now sits in Amrize Building Envelope with Elevate, GenFlex, Malarkey and Gaco.
| Date | Event | Source |
|---|---|---|
| 1978 | First Duro-Last roof installed; founder John R. Burt was 58 | Duro-Last history |
| 1981 | Duro-Last incorporated with 7 employees and $200,000 in sales | Duro-Last history |
| 2011 | Tom Saeli becomes first non-family CEO | Duro-Last history |
| Feb. 7, 2023 | Holcim agrees to buy Duro-Last for $1,293 million; pro forma net sales $540 million; 840 employees | Holcim release |
| April 3, 2023 | Holcim completes the acquisition | Holcim release |
| June 23, 2025 | Amrize spin-off completed; Amrize lists on NYSE (AMRZ) and SIX | Holcim release |
| 2025 | 8th plant opens in Kernersville, North Carolina (104,000 sq ft); Texas operations move to a 130,000 sq ft Dallas plant | Duro-Last history |
Sister brands are listed on the Amrize Building Envelope page. Amrize’s other single-ply lines are covered in our commercial membrane market share report.
Duro-Last lawsuits and complaints: what the court record shows
CourtListener’s RECAP index lists 20 federal dockets filed since January 2005 with Duro-Last in the case name; 19 show a termination date, 11 of them within a year of filing. A docket is a filing, not a finding of fault. Two published appellate opinions describe the best-documented disputes in detail.
| Case | Court and date | What the record says |
|---|---|---|
| Phillips v. Duro-Last Roofing, Inc., 973 F.2d 869 | 10th Cir., Aug. 25, 1992 | An installer fell when, he claimed, Duro-Last material tore; a $187,000 jury verdict was vacated and remanded for a new trial over a comparative-fault jury instruction |
| Duro-Last, Inc. v. Custom Seal, Inc., 321 F.3d 1098 | Fed. Cir., Feb. 28, 2003 | Duro-Last sued over its stack-flashing and corner patents (4,652,321 and 4,872,296); the court reinstated the jury’s verdict that both were invalid as obvious and affirmed no inequitable conduct |
Sources: Caselaw Access Project texts of Phillips and Duro-Last v. Custom Seal.
| Nature of suit (federal dockets 2005 to 2025) | Dockets | Examples |
|---|---|---|
| Contract | 5 | Safeway Inc. v. Duro-Last (D. Colo., 2010); GG & A Central Mall Partners v. Duro-Last (W.D. Okla., 2016); Duro-Last v. J.A. Taylor Roofing (S.D. Fla., 2006, Duro-Last as plaintiff) |
| Product liability | 3 | Attagirl Properties v. Duro-Last (E.D. Cal., 2009); American Home Assurance v. Duro-Last (W.D. Tex., 2019) |
| Insurance | 3 | Employers Insurance Co. of Wausau v. Duro-Last (E.D. Mich., 2011) |
| Patent | 3 | Custom Seal v. Duro-Last (E.D. Tex., 2011; E.D. Mich., 2012) |
| Trademark (Duro-Last as plaintiff) | 2 | Duro-Last v. Nutech Paint (E.D. Mich., 2014) |
| Bankruptcy adversary proceedings | 2 | Angell, Trustee v. Duro-Last (Bankr. E.D.N.C., 2025) |
| Other or uncoded | 2 | Willis v. Duro-Last (S.D. Miss., 2012); Mack Trucks v. Duro-Last (D. Md., 2016) |
Source: CourtListener RECAP search for “Duro-Last” in the case name, filed after January 1, 2005, run October 19, 2026. State-court cases are not in this count. For complaints, owner and contractor threads on Reddit and roofing forums are anecdotes, so the practical check is the warranty: Duro-Last’s Quality Assurance line is 866.284.9424.
Finding Duro-Last roofing contractors near you
Duro-Last sells through authorized contractors, and its Quality Assurance technical representatives do a “hands and knees” inspection of every commercial installation before a warranty issues, per the warranties page. Duro-Last’s find-a-contractor form takes a project ZIP code and contact details, or owners can call 800.248.0280; the page shows no public contractor directory or map.
Duro-Last’s 25 and 30-year requirement sheet names four contractor levels, standard, Master, Elite and Platinum, with pricing tied to level on the contractor portal. Ask these questions before signing a Duro-Last bid:
- Which warranty form number will be issued (for example DL280016 Supreme or DL280010 Basic), and what is its leak-notice deadline: 72 hours or 14 days?
- Which membrane and thickness is quoted, and does it qualify for the term promised: 60 mil for 25 years, 80 mil roll goods for 30 years?
- For an Ultra high-wind warranty, what wind speed will be written into the blank exclusion line, and does the design meet Duro-Last’s TB 163 requirements?
- Is the job a recover or a tear-off, how many inches of existing roof come off, and is insulation installed in 2 layers with 6 in staggered joints where code requires it?
- Will edge metal come from Exceptional Metals or Duro-Last, which the 25 and 30-year forms require?
- For hail coverage, is there a 1/4 in Duro-Guard cover board or 1-1/2 in Duro-Guard ISO on top, as the hail requirement sheet specifies?
- What fastener pull values (250 lb minimum on 25 and 30-year jobs) will the contractor record, and will the owner get the test report?
On repairs, the warranty forms let Duro-Last choose the repair method and product, and the owner booklet covers only sealants bought from Duro-Last; our PVC roof repair guide compares Duro-Last’s repair and cleaning rules with Sika, Carlisle and GAF. Over an existing metal roof, Duro-Last sells a separate metal retrofit system; see our metal retrofit roofing guide.
Duro-Last vs TPO and other PVC: which should you pick?
Pick the Duro-Last line by the condition on your roof, then confirm the warranty form. The decision table maps common building situations to a starting point drawn from the data sheets and requirement sheets above; a design professional still sets wind, fire and insulation values for the specific building.
| Your situation | Starting point | Why, with the threshold |
|---|---|---|
| Want leak-related interior damage covered | Duro-Last flagship or DLX with a Supreme warranty | Only Supreme covers consequential damage, up to $2,000,000 for 15 years |
| Want a 25-year term | DL60, DLX60 or another 60 mil line | 25-year NDL needs 60 mil minimum; no consequential or hail coverage |
| Want a 30-year term | DLX80, Duro-Tuff 80, Duro-Fleece 80 or EV 80 | 30-year NDL needs 80 mil; the custom-fab flagship is not eligible |
| Hail-prone region | 50 mil or thicker with an Ultra hail warranty | Covers hail up to 1 inch for a maximum of 15 years; cover board or 1-1/2 in ISO required |
| Grease, oils or harsh chemicals on the roof | Duro-Last EV (KEE) or a KEE membrane such as FiberTite | EV adds Dow Elvaloy KEE; get the specific chemical approved in writing |
| Recover over aged BUR, gypsum or lightweight concrete | Duro-Fleece, adhered | Fleece back is listed for direct adhesion to those substrates |
| Large open roof, lowest first cost | A 60 mil TPO, including Duro-TECH | 2026 report: TPO $7 to $12 per sq ft vs PVC $9 to $14 |
| Colored roof required by design | Duro-Tuff or Duro-Fleece | 12 colors vs 5 on the flagship; darker colors reflect less heat (flagship dark gray aged SRI 23 to 25 vs 85 for white) |
For the KEE alternative, see our FiberTite roofing review; for brand-by-brand PVC pricing, see our PVC roof cost guide.
Sources
- Duro-Last, Duro-Last PVC membrane page, 2-Minute Fact Sheet (rev. 3.24.25) and 40, 50 and 60 mil product data sheets (rev. Aug. to Oct. 2025), checked October 2026.
- Duro-Last, warranties page, sample Supreme, Basic and Ultra High Wind warranty forms dated 06.04.2025, 25 and 30-Year Warranty Requirements (rev. 03/07/2024) and Hail Warranty Requirements (rev. 10/19/2023).
- Duro-Last, FAQ, history timeline and Protecting Your Investment owner booklet, checked October 2026.
- Holcim, releases of February 7, 2023, April 3, 2023 and June 2025 on the Duro-Last acquisition and the Amrize spin-off.
- Carlisle SynTec, Sure-Flex PVC data sheet (10.10.25); Sika, Sarnafil G410-60 (Nov. 2023) and G410-80 EnergySmart (Sept. 2022) data sheets.
- Ohio STS contract 7756400506 and Duro-Last GSA contract GS-07F-5689P price list, effective 2009; U.S. Bureau of Labor Statistics CPI-U series CUUR0000SA0.
- Caselaw Access Project opinions in 973 F.2d 869 (10th Cir. 1992) and 321 F.3d 1098 (Fed. Cir. 2003); CourtListener RECAP docket search, October 19, 2026.
Frequently asked questions
Is Duro-Last roofing good?
On the 2025 Duro-Last data sheets, the 50 mil flagship PVC passes every ASTM D4434 test, with 438 x 390 lbf/in breaking strength against a 200 lbf/in minimum and 28 mil of PVC above the scrim against a 16 mil minimum. The factory welds up to 85% of seams. Results still depend on the authorized installer, roof drainage and the warranty form issued.
How much does a Duro-Last roof cost?
Duro-Last does not publish installed prices. The Roofing Brief 2026 baseline for PVC is $9 to $14 per sq ft installed. A public 2009 Ohio contract priced a 50 mil mechanically fastened Duro-Last recover at $4.21 per sq ft, about $6.65 in 2026 dollars by CPI-U, before tear-off, insulation or adhered attachment.
How long does a Duro-Last roof last?
The longest Duro-Last warranties run 25 years on 60 mil membrane and 30 years on 80 mil roll goods, and the Duro-Life 600 system is marketed for 50 years with DuPont XPS insulation. Duro-Last publishes no single service-life figure for the flagship membrane; it cites more than four decades of performance since its first roof in 1978.
Who bought Duro-Last roofing?
Holcim bought Duro-Last for $1,293 million, announcing the deal on February 7, 2023 and closing it on April 3, 2023. Holcim then spun off its North American business as Amrize, which began trading on June 23, 2025. Duro-Last is now a brand of Amrize Building Envelope LLC, alongside Elevate, GenFlex, Malarkey and Gaco.
Is Duro-Last PVC or TPO?
Both. The flagship Duro-Last membrane and the Duro-Last X, Duro-Tuff and Duro-Fleece lines are PVC tested to ASTM D4434, and Duro-Last EV adds Dow Elvaloy KEE. In 2025 Duro-Last added Duro-TECH TPO in 45, 60 and 80 mil, tested to ASTM D6878, with 30 mil of TPO above the scrim on the 60 mil sheet.
Is there a Duro-Last roofing price list?
The current Duro-Last price list sits on its contractor portal under Sales/Price Lists and is not public. The most detailed public list is a 2009 GSA and Ohio STS schedule that priced 40 mil membrane at $0.83 per sq ft and 50 mil at $0.93 per sq ft, material only. Public agencies now buy through the Duro-Last TIPS-USA job order contract.
Can a Duro-Last roof be installed on a house?
Yes, with proper design. The Duro-Last FAQ says its PVC and Duro-TECH TPO systems can be installed on any roofing surface, and it offers 15-year and 20-year Residential Material Limited Warranties, which exclude consequential damages. Most homes use it on low-slope sections; the 2009 Ohio schedule added $1.47 per sq ft for slopes steeper than 4:12.
Does the Duro-Last warranty cover leak damage inside the building?
Only the Supreme warranty does. The June 2025 Supreme 15-year sample form covers reasonably foreseeable leak-related interior damage up to $2,000,000 when a system defect or installer workmanship causes it, and it requires notice within 72 hours of discovery. Basic, Ultra and Residential warranties exclude consequential damages.