SAINT-GOBAIN NEWS PAGES 6 & 7 OFFICIAL SUPPORTER PAGE 5 SEPTEMBER 2023 N°97 SHAREHOLDERS LETTER TO SAINT-GOBAIN FINALIZES THE ACQUISITION OF BUILDING PRODUCTS OF CANADA PAGE 4 OFFICIAL SUPPORTER PARIS 2024 FURTHER RECORD RESULTS IN H1 2023 2023 OUTLOOK UPGRADED SALES €25.0bn OPERATING INCOME €2.8bn 11.3% operating margin RECURRING NET INCOME* €1.8bn FREE CASH FLOW €2.2bn * Net attributable income excluding capital gains and losses on disposals, asset write-downs and material non-recurring provisions.

A FEWWORDS FROM BENOIT BAZIN Chief Executive Officer of Saint-Gobain 2 LETTER TO SHAREHOLDERS N°97 H1 2023 RESULTS “In a difficult macroeconomic environment, the Group once again demonstrated its strategic positioning as worldwide leader in light and sustainable construction and the relevance of its “Grow & Impact” strategy. Thanks to our teams’ agility, entrepreneurial spirit and dedication, we once again delivered record earnings, margins, and value creation in the first half of 2023. Our organization by country has enabled the Group to outperform, both by proactively adapting our operations on the ground but also by making selective growth investments, including in additional production capacity and with acquisitions such as Building Products of Canada. Over 60% of our earnings are now generated in North America, Asia and emerging countries, where trends are improving and the growth outlook is supported by demographics and rapid urbanization. In Western Europe, renovation – our biggest market – continues to show good resilience as expected, with stimulus measures and regulations aimed at accelerating the path to carbon neutrality; structural demand for new construction is growing, even though additional financing costs are temporarily impacting the sector. Despite a moderate slowdown in its markets in the short-term, in 2023 Saint-Gobain will deliver a double-digit operating margin for the third consecutive year. Over the medium term, I am confident that the Group’s new profile places it firmly on a sustainable profitable growth trajectory.” • Like-for-like sales up 1.6% • Record margin of 11.3% and record operating income of €2,813m despite a difficult environment • Significant operating income growth in North America, Asia and emerging countries, which represent over 60% of the Group’s earnings • Strong increase in free cash flow, up 30% at €2,192m • Double-digit operating margin expected in full-year 2023 for the third consecutive year, demonstrating the Group’s resilience A GROWTH STRATEGY BUILT ON SUSTAINABLE SOLUTIONS AND INNOVATION Saint-Gobain continues to outperform its markets thanks to the pertinence of its strategic positioning at the heart of energy and decarbonization challenges, and to the strength of its local organization by country, which enables it to offer comprehensive solutions to its customers: ►A comprehensive range of solutions accelerating growth Saint-Gobain’s solutions for renovation, the building envelope and innovative new light construction methods drastically reduce CO2 emissions while increasing user wellbeing (thermal and acoustic comfort, light, air quality and hygiene). Each country CEO has adopted a specific local approach. ►A sustainable, innovative offer Innovation at Saint-Gobain follows various transversal axes: • Light construction systems; • Sustainable solutions protecting natural resources; • Materials and solutions to conquer new markets; • Decarbonizing production processes. In a difficult macroeconomic environment, the Group continues to demonstrate its resilience and its strong operating performance, thanks to its focused strategy and its proactive commercial and industrial initiatives. The Group continues to focus on developing sustainable and innovative solutions with a positive impact, supported by strong innovation and investments for growth. 2023 will therefore mark another successful year for Saint-Gobain, with the continued implementation of its “Grow & Impact” priorities. The Group confirms its assumptions for its markets in 2023 with contrasting trends: a marked decline in new construction in certain regions but good resilience overall in renovation, and is raising its operating margin guidance. Amid a moderate market slowdown, Saint-Gobain is now targeting for full-year 2023 a double-digit operating margin, for the third consecutive year. For second-half 2023, the Group is targeting an operating margin of between 9% and 11%, in line with the “Grow & Impact” strategic plan target.

* Sales: contribution to Group total and like-for-like variation H1-2023/H1-2022 H1 2023 RESULTS LETTER TO SHAREHOLDERS N°97 3 4%of Group sales, o/w*: ASIA-PACIFIC +6.4% like-for-like (*) HIGH PERFORMANCE SOLUTIONS 20%of Group sales, o/w*: Construction and Industry (13%): - 0.9% Mobility (7%): + 20.2% +6.4% like-for-like (*) RESULTS BY SEGMENT AMERICAS 19%of Group sales, o/w*: North America (14%): + 5.5% Latin America (5%): - 2.5% +3.4% like-for-like (*) 16,5% 852 H1-2023 723 7.8% 16.9% H1-2022 H1-2023 130 12.5% 129 12.7% H1-2022 633 12.3% H1-2023 594 12.9% H1-2022 SALES €4,784m SALES €1,036m SALES €5,163m OPERATING INCOME (€m) AND MARGIN (%) OPERATING INCOME (€m) AND MARGIN (%) OPERATING INCOME (€m) AND MARGIN (%) SOUTHERN EUROPE - ME & AFRICA 31%of Group sales, o/w*: France (24%): + 1.8% Spain - Italy (4%): + 4.3% +2.6% like-for-like (*) 688 8.6% H1-2023 693 8.9% H1-2022 SALES €7,976m OPERATING INCOME (€m) AND MARGIN (%) 572 H1-2023 8.6% 690 8.2% H1-2022 NORTHERN EUROPE SALES €6,674m 26%of Group sales, o/w*: Nordics (12%): - 3.9% UK - Ireland (5%): + 2.6% Germany - Austria (3%): - 9.3% - 3.7% like-for-like (*) OPERATING INCOME (€m) AND MARGIN (%)

4 LETTER TO SHAREHOLDERS N°97 FOCUS... On September 1, 2023, Saint-Gobain completed the acquisition announced on June 12, 2023 of Building Products of Canada (BPC), a privately owned manufacturer of residential roofing shingles and wood fiber insulation panels in Canada, for C$1,325 million (approximately €925 million) in cash. STRATEGIC BENEFITS The acquisition of Building Products of Canada, a leading roofing and exterior building products player in Canada, will add roofing materials to the range of sustainable construction solutions available to the Group’s Canadian customers. Saint-Gobain’s innovation expertise will allow the Group to develop a broader, more sustainable range of solutions in Canada. With this acquisition, Saint-Gobain takes a logical step to reinforce its leadership in light and sustainable construction in the Canadian market. VALUE CREATION & SYNERGIES to cross-selling opportunities with Kaycan (leveraging the full exterior solutions offering) and using Building Products of Canada channels to sell other Saint-Gobain product categories and expand their product range in roofing (with Landmark® shingles and GCP Ice & Water Shield® waterproofing membranes). Canada is a key growth market for Saint-Gobain’s light and sustainable construction solutions, with significant structural needs in housing, a fast-growing population driven by immigration, and a renovation market supported by ageing buildings. The Group’s pro forma sales in the country have doubled over the past two years, from C$0.9 billion to C$1.8 billion. circular economy know-how and recycle Building Products of Canada shingle waste, leveraging CertainTeed’s partnership with Asphaltica for recycling asphalt shingles used in roofing. Significant synergy opportunities are estimated at C$50 million by year 3 following the closing of the transaction. This includes cost synergies of C$40 million which are expected to be captured through the combination of Building Products of Canada’s materials procurement with that of Saint-Gobain, the implementation of Saint-Gobain’s World Class Manufacturing program leveraging best practices from its industryleading position across its 17 US roofing plants, optimization of freight and logistics costs across North America, as well as SG&A cost optimization. Sales synergies of C$10 million are expected thanks This acquisition will create value for Saint-Gobain’s shareholders by year 3 following closing and will be EPS (Earnings Per Share) accretive from year 1. It will provide an enhanced proposition for our customers thanks to a full-range offer: 1. Leverage our innovation for a unique comprehensive solutions offering: bring CertainTeed building-integrated photovoltaic (BIPV) Solstice® shingles to the Canadian market, enrich the Building Products of Canada offer with our ClimateFlex® allweather technology, our industry-leading reflective shingle Solaris®, our widest range of Landmark® premium products, and our best-in-class Roof System that utilizes all CertainTeed roofing components including GCP underlayment; 2.Drive sustainability in building materials: leverage CertainTeed’s INTERIOR SOLUTIONS EXTERIOR SOLUTIONS THE ACQUISITION OF BUILDING PRODUCTS OF CANADA REINFORCES THE GROUP’S LEADERSHIP IN CANADA

5 LETTER TO SHAREHOLDERS N°97 FOCUS... easily converted into homes and student housing after the event. The plasterboard will then have a second life on new building sites in the Paris region, as part of a reuse experiment. • Innovation and technological feats: the buildings in the Athletes’ Village are mid-rise structures with wooden façades. Weber, a leader in industrial mortars and a SaintGobain Group subsidiary, worked with manufacturers to propose an innovative external thermal insulation system for wooden façades on mid-rise buildings (max. 28 meters). • A work of art made in Alsace: the sculpture topping the Signal Tower located right in the middle of the Athletes’ Village, a reinterpretation of the Olympic rings, was made in Saint-Gobain’s glass factory in Alsace using local manufacturing expertise. Take a 4-minute visit of this unique project. To find out more, click here: https://www.saint-gobain.com/en/ supporteur-officiel-paris-2024 objectives. In the Athletes’ Village, an open-air laboratory for the sustainable construction of tomorrow, the Group has put in place innovative and differentiating solutions designed especially for the Village, which is intended to be a role model in terms of being both environmentally virtuous and entirely modular: • Building materials transported on the river: Point.P, a Saint-Gobain Group brand, delivers construction materials on two barges. Inland waterway transportation reduces CO2 emissions by 50%, or 5.5kg CO2 per ton delivered. For this specific site, 1,500 tons of materials have been delivered and 60 25-ton trucks avoided since the start of the year. In addition to curbing CO2 emissions, river transport reduces traffic nuisances and avoids potential delivery delays caused by traffic congestion in the Paris region. • A full-scale experiment in the reuse of construction materials: the interior walls of the Village buildings, co-developed by Saint-Gobain’s Placo® subsidiary and built for the Paris 2024 Olympic and Paralympic Games, have been especially designed to be dismantled and the majority of materials reused. More than 20,000 people will be housed here during Paris 2024. From 2025, the Village will be transformed to accommodate 120,000 sq.m. of activities, offices and shops and more than 2,800 new homes. A total of 60,000 sq.m. of demountable partitions will be available for reuse after the competition and will allow athletes’ dwellings to be On June 22, 2023 Saint-Gobain announced the signing of a partnership with the Paris 2024 Olympic and Paralympic Games Organizing Committee as “Official Supporter” for renovation and sustainable construction solutions. Shared values… The Group shares Paris 2024’s ambition to create a responsible, fair and inclusive Olympics and is providing its expertise in sustainable construction for the benefit of both athletes and spectators. …at the service of a responsible project “This partnership is an opportunity for Saint-Gobain to demonstrate in concrete terms, through the completion of major construction works, the Group’s responsible commitment and the excellence of its solutions in sustainable and lightweight construction as well as renovation,” explains Benoit Bazin, Saint-Gobain’s CEO. Tony Estanguet, President of Paris 2024: “We are delighted that the Saint-Gobain Group is joining the Paris 2024 adventure. With SaintGobain, we are driven by the same ambition to offer environmentally responsible and exemplary Games, inspired by a typically French pioneering and innovative spirit.” The projects in which the SaintGobain Group has participated in Paris and in the French host cities of the Paris 2024 Olympic and Paralympic Games are all demonstrations of its capacity to innovate, to offer tailor-made solutions and to meet the organizers’ environmental SAINT-GOBAIN BECOMES AN “OFFICIAL SUPPORTER” OF THE PARIS 2024 OLYMPICS AND PARALYMPIC GAMES

CONSTRUCTING A SUSTAINABLE FUTURE Saint-Gobain is publishing its first sustainable construction magazine, Constructing a Sustainable Future. This 84-page first edition looks at the environmental and societal impacts of the construction sector, takes in different views from experts and showcases exemplary projects to inspire all our stakeholders. Click here to browse the digital version and sign up for future editions SAINT-GOBAIN NEWS SAINT-GOBAIN FRANCE, THE CITY OF PARIS AND ITS LANDLORDS JOIN FORCES TO RECYCLE GLASS AND PLASTERBOARD Renovating buildings, homes and public infrastructure is a key element to the success of the Paris Air Quality, Energy & Climate Action Plan, and will enable the goals of achieving carbon neutrality by 2050, having “zero recoverable waste in landfill” and adapting the building stock to climate change to be met. This ecological transition launched by the City of Paris requires close cooperation with stakeholders in the real estate sector. SaintGobain France, the City of Paris and the city’s landlords have joined forces to reduce the building industry’s environmental footprint: on the one hand by developing closed-loop recycling of building site waste (recycling window glazing and using it to make new, more sustainable windows) and on the other, by increasing the percentage of recycled content in construction solutions, particularly glass and plasterboard. PROFOUND CHANGES IN HEALTHCARE FACILITIES Bringing more flexibility into a sector shaped by numerous health and safety constraints to guarantee patient care under good conditions is no easy task. Healthcare establishments – whether old or new – must be redesigned to make them more modular, flexible and open. Climate change is another major challenge. Reducing CO2 emissions and being more sustainable and low-carbon should lead to buildings with an optimal design in terms of thermal properties, energy, carbon impact and summer comfort. All issues for which Saint-Gobain provides practical solutions to: • Take care of the design and construction quality of these buildings, in terms of thermal, acoustics and light, as well as air quality and hygiene; • Allowmodularity and adaptability of interior spaces; • Renovate and thereby reduce energy consumption and CO2 emissions. White paper on healthcare facilities (*). Guide tohealthcare infrastructure (*). STRATEGY ENERGY SAVINGS AT SCHOOLS Whether new or old, school buildings must also adapt to the climate emergency, as well as evolving to keep pace with new teaching methods. This dual challenge must take center stage in all construction and renovation projects for the 65,000 establishments in France today. To this end, the Group has carried out a comprehensive analysis of these growth markets, notably through the actions of SaintGobain Solutions France. This proactive approach has resulted in a white paper, Educational establishments: current and future challenges (*). The white paper addresses issues such as energy performance, designing the school of tomorrow, and improving comfort and quality of use for students and teachers. All issues for which Saint-Gobain provides practical solutions to: • Treat the building shell and its acoustics; • Improve indoor air quality; • Enhance lighting comfort; • Decarbonize at a competitive cost. CHALLENGES MARKETS AND CUSTOMERS MARKETS AND CUSTOMERS *In French

ONE PRECISION ASSEMBLIES: A COMPREHENSIVE RANGE OF SOLUTIONS FOR THE RESIDENTIAL CONSTRUCTION SECTOR IN THE US In May 2023 in the US, SaintGobain launched One Precision Assemblies (OPA), its first-ever prefabricated residential construction solution for walls, floors, ceilings and roofing. In 2022, two pilot projects were launched with fullyconstructedpanelsdevelopedwith Saint-Gobain products, built at a partner plant, shipped to a building site and assembled to form two energy-efficient individual homes in Mystic, Connecticut, and Keene, New Hampshire. These homes currently consume half the energy consumed by a traditional house, resulting in an excellent cost/ performance ratio. Manufacturing lead times are also considerably less: for a fully customized house, in-factory production of the wall panels takes a week, while just one day is needed to assemble them on site, compared to between four and nine months approximately in more conventional building projects, depending on the project’s location, scale and complexity, and on the builder. COMFORT FOR SENIORS! In France from January 1, 2024, new financial aid will be available for people to better adapt their homes for old age. Ma Prime Adapt’ will be available to lowincome and very low-income households, but will no doubt have a positive knock-on effect on the issue of age-proofing homes. The La Maison SaintGobain website has published a guide to help professionals and homeowners adapt homes to ensure comfortable “ageing at home”. This French initiative is a response to the global challenge of an ageing population. The practical, comprehensive guide will enable trade clients to advise their own customers and learn about the technical rules and best practices for age-proofing homes. La Maison Saint-Gobain can also provide support to individuals, from the birth of an idea and contact with professionals to the execution of their projects. Follow this link to download the La Maison Saint-Gobain guide. (*) INITIATIVES 3D PRINTINGWORLDWIDE Saint-Gobain Weber Beamix, a specialist in 3D concrete printing in the Netherlands, has developed Weber Mobile Setup, an innovative solution to demonstrate the potential of printed concrete. Everything you need for 3D concrete printing in a single container! Weber Mobile Setup is ready to use and can be shipped anywhere in the world. It takes less than 48 hours to get it up and running to print elements on demand. A unique service to convince any company, anywhere, of the benefits of 3D concrete printing without the initial outlay. The Weber Mobile Setup prototype has already proven its worth in the Netherlands, the UK, Hungary and the United States. INNOVATION INNOVATION SAINT-GOBAIN TO JOIN EURO STOXX 50 In the context of a review of the composition of benchmark STOXX indices, on September 18, 2023 Saint-Gobain will join the EURO STOXX 50. The EURO STOXX 50 is composed of the 50 leading listed bluechip companies in the eurozone based on market capitalization, adjusted for free float as of August 31, 2023. Saint-Gobain’s inclusion in EURO STOXX 50 is recognition of its profound transformation, begun at the end of 2018, which has significantly improved its growth and profitability profile. Since that time, Saint-Gobain has outperformed, achieving a two-fold increase in its earnings per share, a three-fold increase in its free cash flow generation, improving its return on capital by 540 basis points and is targeting a double-digit operatingmargin in 2023 for the third consecutive year. FINANCE *In French

8 LETTER TO SHAREHOLDERS N°97 SHAREHOLDER’S NOTEBOOK SHAREHOLDER’S NOTEBOOK Recent performance at 08/31/2023 (%) Saint-Gobain share CAC 40 Performance since le 01/01/2021 +60.4% +31.8% Performance since le 01/01/2023 +31.8% + 13.0% — (1) Saint-Gobain share — CAC 40 TOTAL NUMBER OF SHARES (at June 30, 2023) 509 million OWNERSHIP STRUCTURE (at June 30, 2023 – %, estimated) 9.4% Group Savings Plan (employee shareholders) 29.6% Institutional investors: Americas – Asia 19.6% Institutional investors: France 7.4% Private shareholders 34.0% Institutional investors: Other Europe SAINT-GOBAIN SHARE PERFORMANCE 01/01/2021 TO 08/31/2023 €60.160(1) 08/31/2023 SIGN UP FOR THE E-LETTER TO SHAREHOLDERS To receive your copy of the Letter to Shareholders and keep abreast of all the latest Saint-Gobain news, sign up for the e-Letter to Shareholders, in the Shareholders section of www.saint-gobain.com or send an e-mail to actionnaires@saint-gobain.com. €66.930(1) 01/12/2022 DATES FOR YOUR DIARY FINANCIAL AGENDA Sales for the third quarter of 2023: October 26, 2023, after close of trading on the Paris stock market 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 01/01/21 01/02/21 01/03/21 01/04/21 01/05/21 01/06/21 01/07/21 01/08/21 01/09/21 01/10/21 01/11/21 01/12/21 01/01/22 01/02/22 01/03/22 01/04/22 01/05/22 01/06/22 01/07/22 01/08/22 01/09/22 01/10/22 01/11/22 01/12/22 01/01/23 01/02/23 01/03/23 01/04/23 01/05/23 01/06/23 01/07/23 01/08/23 YOUR CONTACTS Saint-Gobain’s Shareholder Relations Department will be pleased to answer any enquiries. Please feel free to contact them: • By dialing: (from France) 0 800 32 33 33 or +33 (0)1 88 54 05 05 (from outside France) • Online, at www.saint-gobain.com or www.lamaisonsaintgobain.fr • By e-mail, at: actionnaires@saint-gobain.com Managing Editor: Vivien Dardel Manager, Individual Shareholders: Abiba Tinor N°ISSN 1245-3978 Design: Cédric Bertandeau Photo credits: Saint-Gobain photo library • Via the Saint-Gobain Shareholder App • By post: Compagnie de Saint-Gobain Service Actionnaires Tour Saint-Gobain 12 place de l’Iris 92096 La Défense Cedex