DCT
1:25-cv-00191
CertainTeed LLC v. GAF Energy LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: CertainTeed LLC (Delaware)
- Defendant: GAF Energy LLC (Delaware)
- Plaintiff’s Counsel: Scott Douglas & McConnico LLP; Latham & Watkins LLP
- Case Identification: [CertainTeed LLC](https://ai-lab.exparte.com/party/certainteed-corp) v. [GAF Energy LLC](https://ai-lab.exparte.com/party/gaf-energy-llc), 1:25-cv-00191, W.D. Tex., 02/12/2025
- Venue Allegations: Plaintiff alleges venue is proper because Defendant has a regular and established place of business in the district—a 450,000-square-foot manufacturing facility in Georgetown, Texas—where it allegedly manufactures the infringing products, transacts business, and hires employees.
- Core Dispute: Plaintiff alleges that Defendant’s Timberline Solar Energy Shingles infringe three patents related to photovoltaic roofing elements, focusing on the specialized tie layer systems used to adhere solar components to roofing substrates.
- Technical Context: The technology at issue is building-integrated photovoltaics (BIPV), a field that seeks to combine the functions of traditional roofing materials with solar power generation in a single product.
- Key Procedural History: The complaint alleges that a named inventor on all three asserted patents, Ming-Liang Shiao, formerly worked for Plaintiff before joining Defendant, where he was allegedly a key contributor to the development of the accused product. Plaintiff further alleges that Defendant cited all three asserted patents as prior art during the prosecution of its own patents. These facts are presented to support allegations of willful infringement and to assert assignor estoppel, which may bar Defendant from challenging the patents’ validity.
Case Timeline
| Date | Event |
|---|---|
| 2007-11-06 | Earliest Priority Date for ’796, ’653, and ’465 Patents |
| 2013-02-19 | U.S. Patent No. 8,375,653 Issued |
| 2013-05-14 | U.S. Patent No. 8,438,796 Issued |
| 2014-03-01 | Named Inventor Ming-Liang Shiao allegedly began working for GAF |
| 2015-11-03 | U.S. Patent No. 9,178,465 Issued |
| 2022-01-01 | GAF allegedly launched the Accused Products |
| 2025-02-12 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,438,796 - "Photovoltaic Roofing Elements Including Tie Layer Systems, and Roofs Using Them, and Methods for Making Them," Issued May 14, 2013 (’796 Patent)
The Invention Explained
- Problem Addressed: The patent’s background section describes the difficulty of creating a "long-lived physical connection" between the materials of an encapsulated photovoltaic (PV) element and a roofing substrate, particularly when the PV element has low surface tension, making adhesion problematic (Compl. ¶28; ’796 Patent, col. 1:47-62).
- The Patented Solution: The invention proposes using a specific "tie layer system" positioned between the PV element and the roofing substrate to create a durable bond (’796 Patent, Abstract). The core of the solution is the composition of this tie layer, which is claimed as "a blend of functionalized EVA and polyolefin" designed to effectively join the two otherwise incompatible surfaces (’796 Patent, Claim 1). The general structure is depicted in the patent's figures, showing a PV element, a roofing substrate, and the tie layer system joining them (’796 Patent, Fig. 3).
- Technical Importance: This technology aims to improve the structural integrity and weather resistance of solar shingles, addressing a key manufacturing and durability challenge for building-integrated photovoltaics (Compl. ¶29).
Key Claims at a Glance
- The complaint asserts independent claims 1 (a photovoltaic roofing element) and 25 (a method of making a photovoltaic element) (Compl. ¶45).
- Independent Claim 1 requires:
- An encapsulated photovoltaic element with a bottom layer material having a surface tension no greater than 35 dyne/cm.
- A roofing substrate.
- A tie layer system comprising a blend of functionalized EVA and polyolefin, disposed between and joining the PV element and the substrate.
- Independent Claim 25 requires a method of making the element of claim 1 by arranging the tie layer system between the substrate and the PV element, and then joining them with that system.
- The complaint asserts dependent claims 3, 5, 7, and 8, and reserves the right to assert others (Compl. ¶45).
U.S. Patent No. 8,375,653 - "Photovoltaic Roofing Elements Including Tie Layer Systems," Issued February 19, 2013 (’653 Patent)
The Invention Explained
- Problem Addressed: Like the ’796 Patent, this patent addresses the challenge of achieving durable adhesion between low-surface-tension PV elements and conventional roofing substrates (’653 Patent, col. 1:47-62). The USPTO recognized that the invention "address[es] the problem of long-lived physical connection" between these components (Compl. ¶29).
- The Patented Solution: The invention is a photovoltaic roofing element that incorporates a "tie layer system" to join the encapsulated PV element to the roofing substrate (’653 Patent, Abstract). Unlike claim 1 of the ’796 Patent, which specifies a particular chemical blend for the tie layer, claim 1 of the ’653 Patent more broadly claims the structural arrangement of a "tie layer system" without limiting its composition to a specific blend in the independent claim (’653 Patent, Claim 1).
- Technical Importance: The invention provides a structural solution for integrating PV elements into roofing products, aiming to enhance product longevity and performance in outdoor conditions.
Key Claims at a Glance
- The complaint asserts independent claims 1 (a photovoltaic roofing element) and 12 (a method of making the element) (Compl. ¶76).
- Independent Claim 1 requires:
- An encapsulated photovoltaic element with a bottom layer material having a surface tension no greater than 35 dyne/cm.
- A roofing substrate.
- A tie layer system disposed between and joining the PV element and the substrate.
- Independent Claim 12 requires a method of making the element of claim 1 by arranging the tie layer between the components and joining them.
- The complaint asserts dependent claims 2, 4, 5, and 15, and reserves the right to assert others (Compl. ¶76).
U.S. Patent No. 9,178,465 - "Photovoltaic Roofing Elements Including Tie Layer Systems and Roofs Using Them," Issued November 3, 2015 (’465 Patent)
Technology Synopsis
This patent also discloses a photovoltaic roofing element using a tie layer system to bond a PV element to a roofing substrate (’465 Patent, Abstract). The invention is distinguished by its focus on the specific physical properties of the tie layer; the claims require the tie layer to include a polymeric material with specific viscoelastic properties defined by a "Chang viscoelastic window," which is a method of characterizing pressure-sensitive adhesives to ensure durable bonding (’465 Patent, Claim 1).
Asserted Claims
Independent claim 1 is asserted (Compl. ¶106).
Accused Features
The complaint alleges that the adhesive used in the tie layer system of the GAF Timberline Solar Energy Shingles is a polymeric material that exhibits coordinates lying within the claimed Chang viscoelastic window (Compl. ¶¶118-119, 121).
III. The Accused Instrumentality
Product Identification
GAF’s Timberline Solar Energy Shingles and roofing systems comprising the same ("Accused Products") (Compl. ¶32).
Functionality and Market Context
The Accused Products are described as nailable solar shingles intended to function as both a protective roofing material and a generator of electricity (Compl. ¶49). The complaint alleges the shingles have a multi-layer construction comprising an encapsulated PV element, a roofing substrate, and an intermediate tie layer, and offers annotated microscope images as evidence of this structure (Compl. ¶¶52, 56, 58). A provided image of the product's data plate identifies it as part of a "Solar Roofing System" (Compl. ¶50). Plaintiff alleges that GAF and CertainTeed are two of the largest competitors in the U.S. residential solar roofing market (Compl. ¶37).
IV. Analysis of Infringement Allegations
’796 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A photovoltaic roofing element comprising: an encapsulated photovoltaic element having a top surface and a bottom surface, a top layer material at its top surface and a bottom layer material at its bottom surface, | The GAF Timberline Solar Energy Shingle is alleged to be a photovoltaic roofing element that includes an encapsulated PV element, as shown in annotated cross-sectional images. | ¶51-52 | col. 3:41-54 |
| the bottom layer material at the bottom surface of the encapsulated photovoltaic element having a surface tension no greater than 35 dyne/cm; | On information and belief, the bottom layer material of the shingle's PV element has a surface tension below the claimed threshold. | ¶53-54 | col. 4:18-19 |
| a roofing substrate having a top surface; and | The shingle is alleged to comprise a roofing substrate with a top surface, as identified in annotated cross-sectional images. | ¶55-56 | col. 5:45-6:3 |
| a tie layer system comprising a blend of functionalized EVA and polyolefin disposed between the encapsulated photovoltaic element and the roofing substrate and joining the bottom surface... to the top surface... | On information and belief, an adhesive layer in the shingle functions as the tie layer system and is composed of a blend of functionalized EVA and polyolefin. A scanning electron microscopy image shows this adhesive layer. | ¶57-59 | col. 7:41-45 |
’653 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A photovoltaic roofing element comprising: an encapsulated photovoltaic element having a top surface and a bottom surface, a top layer material at its top surface and a bottom layer material at its bottom surface, | The GAF Timberline Solar Energy Shingle is alleged to be a photovoltaic roofing element that includes an encapsulated PV element, supported by product images and annotated cross-sections. | ¶82-83 | col. 3:41-54 |
| the bottom layer material at the bottom surface of the encapsulated photovoltaic element having a surface tension no greater than 35 dyne/cm; | On information and belief, the bottom layer material of the PV element in the accused shingle has a surface tension of less than 35 dyne/cm. | ¶84-85 | col. 4:18-19 |
| a roofing substrate having a top surface; and | The accused shingle is alleged to include a roofing substrate, as identified in an annotated cross-sectional microscope image. | ¶86-87 | col. 5:45-6:3 |
| a tie layer system disposed between the encapsulated photovoltaic element and the roofing substrate and joining the bottom surface... to the top surface... | The accused shingle is alleged to contain a tie layer system situated between the PV element and the roofing substrate, as shown in annotated images. | ¶88-89 | col. 6:4-20 |
Identified Points of Contention
- Technical Questions: A central point of contention may be the specific, technical properties of the materials used in the Accused Products. The complaint alleges, "on information and belief," that the materials meet quantitative thresholds required by the claims, such as the surface tension of the PV element's bottom layer (Compl. ¶¶54, 85), the specific chemical blend of the tie layer in the ’796 Patent (Compl. ¶59), and the specific viscoelastic properties required by the ’465 Patent (Compl. ¶¶119, 121). These allegations will require evidentiary support through discovery and testing, and the defense may argue that its materials fall outside these claimed parameters.
- Scope Questions: What evidence does the complaint provide that the layer identified as the "roofing substrate" (Compl. ¶56, ¶87) in the accused integrated shingle functions as the "roofing substrate" contemplated by the patents, which describe substrates such as asphalt shingles and polymeric tiles as distinct components? (’796 Patent, col. 5:45-67). The court may need to determine if the integrated lower portion of the accused shingle meets the definition.
V. Key Claim Terms for Construction
The Term: "tie layer system" (asserted in all three patents)
- Context and Importance: This term is the technological core of all asserted patents. Its construction will be critical to the infringement analysis, as it defines the adhesive component that allegedly makes the invention novel. The scope given to this term will likely determine whether the adhesive layer in GAF's product (Compl. ¶59) infringes.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes the system’s function broadly as providing "sufficient bond strength to join the bottom surface of the encapsulated photovoltaic element to the top surface of the substrate" and notes it can "comprise other layers of structural features, such as woven or nonwoven mat, a fibrous surface, a patterned surface..." (’796 Patent, col. 6:7-20). This language could support a construction that encompasses a wide range of adhesive structures.
- Evidence for a Narrower Interpretation: The specification also provides highly specific examples, including commercial products (e.g., "HB Fuller HL2688PT"), specific chemical blends (e.g., "a 70% polypropylene/30% EVA blend"), and materials with specific properties (e.g., a Chang viscoelastic window) (’796 Patent, col. 6:45-56; col. 7:46-60). A party could argue the term should be limited to these specific embodiments.
The Term: "roofing substrate" (asserted in ’796 and ’653 Patents)
- Context and Importance: Practitioners may focus on this term because the accused product is an integrated solar shingle, and the parties may dispute which part of the shingle constitutes the "roofing substrate." The complaint identifies a specific layer as the substrate in its annotated images (Compl. ¶56, ¶87).
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent states that the invention can be practiced with "any of a number of types of roofing substrates," listing examples such as polymeric material, metal panels, and bituminous materials, suggesting the term is not narrowly limited (’796 Patent, col. 5:45-55).
- Evidence for a Narrower Interpretation: The specification repeatedly refers to the substrate in the context of conventional roofing products like an "asphalt roofing shingle" or a "polymeric roofing tile" (’796 Patent, col. 5:56-64). A party could argue that the integrated, non-PV portion of the accused shingle is structurally and functionally distinct from these examples and therefore falls outside the claim scope.
VI. Other Allegations
Willful Infringement
The complaint alleges that Defendant's infringement has been willful and deliberate since at least April 2022 (Compl. ¶¶33, 72, 102, 130). The allegations are based on alleged pre-suit knowledge from two primary sources: (1) Defendant's employment of Ming-Liang Shiao, a named inventor on all three asserted patents, who allegedly was a "key contributor" to the development of the Accused Products, and whose knowledge Plaintiff seeks to impute to the company (Compl. ¶¶34-35); and (2) Defendant's disclosure of all three asserted patents to the USPTO as prior art during the prosecution of its own patents related to solar roofing (Compl. ¶36).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of evidentiary proof: can Plaintiff demonstrate through discovery that the materials in the accused GAF Timberline shingle possess the specific, quantitative technical properties required by the claims—such as the 35 dyne/cm surface tension, the "blend of functionalized EVA and polyolefin," and the precise "Chang viscoelastic window" coordinates—all of which are currently alleged on information and belief?
- A key legal and factual question will be the impact of the shared inventor: to what extent can the knowledge of the former CertainTeed inventor, Mr. Shiao, be imputed to GAF to establish the subjective recklessness required for willful infringement, and will the doctrine of assignor estoppel, as argued by Plaintiff, prevent GAF from challenging the validity of the patents he invented?
- The case may also turn on a question of definitional scope: will the term "roofing substrate," which the patents describe in the context of components like asphalt shingles and tiles, be construed to read on the integrated lower portion of the accused all-in-one solar shingle?