Exhibit 99.1

RPM REPORTS FISCAL 2019 FIRST-QUARTER FINANCIAL RESULTS

Medina, Ohio – October 3, 2018 – RPM International Inc. (NYSE: RPM) today reported financial results for its fiscal 2019 first quarter ended August 31, 2018.

First-Quarter Results

Fiscal 2019 first-quarter net sales were a record $1.46 billion, up 8.5% over the $1.35 billion reported a year ago. Including the impact of restructuring charges, first-quarter net income was $69.8 million versus $116.4 million in the year-ago period, and diluted earnings per share (EPS) were $0.52 compared to $0.86 in the year-ago quarter. Income before income taxes (IBT) was $91.9 million compared to $155.3 million reported in the fiscal 2018 first quarter. RPM’s consolidated earnings before interest and taxes (EBIT) were $113.9 million compared to $177.6 million reported in the fiscal 2018 first quarter. The fiscal 2019 first quarter included asset write-offs and other restructuring-related expenses of $39.8 million. Excluding these charges, RPM’s adjusted EBIT was $153.7 million and diluted EPS was $0.76.

“We saw strong top-line sales growth in the first quarter, with organic sales growth up 7.8%, while profitability continued to be adversely affected by rising raw material costs. In addition, bottom-line results reflected the impact of restructuring charges, higher legal and advertising costs in our consumer segment, and the adverse effect of transactional foreign exchange,” stated Frank C. Sullivan, RPM chairman and chief executive officer.

“Our team is focused on driving increased profitability, long-term growth and enhanced value for our shareholders, and we are making good progress in executing on our operating improvement plan, which is specifically designed to increase margins, reduce working capital, and improve overall operating efficiency. During the quarter, we continued our strategic restructuring initiatives, including the reduction of more than 150 positions and the announced closure of four manufacturing facilities, all in line with our 2020 Margin Acceleration Plan,” stated Sullivan.

First-Quarter Segment Sales and Earnings

The company’s industrial segment net sales increased 7.2%, to $782.0 million from $729.8 million reported a year ago, reflecting organic growth of 6.7% and acquisitions contributing an additional 1.6%. Foreign currency translation reduced sales by 1.1%. Industrial segment IBT was $69.1 million compared with $88.9 million a year ago. EBIT was $71.5 million compared to $91.5 million in the fiscal 2018 first quarter. Adjusted EBIT, which excludes the charges mentioned earlier, increased 2.5% to $93.8 million from the year-ago period.

RPM Reports Fiscal 2019 First-Quarter Financial Results

October 3, 2018

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“The industrial segment benefited from especially strong performance in North American waterproofing and a healthy recovery in our businesses serving the oil and gas sector. Leverage to the bottom line was masked by unfavorable transactional foreign exchange expense resulting from the strengthening of the dollar versus certain international currencies,” stated Sullivan. “In the process of realigning our global brands, we adjusted our leadership structure, initiated the closure of two plants and discontinued certain international product lines.”

RPM’s consumer segment generated a 13.6% increase in sales to $485.2 million from $427.1 million in the fiscal 2018 first quarter. Organic sales increased 12.4%, while acquisition growth contributed 1.7%. Foreign currency translation reduced sales by 0.5%. Consumer segment IBT was $51.3 million compared with $72.4 million in the prior-year period. EBIT was $51.5 million compared to $72.6 million in the fiscal 2018 first quarter. Excluding asset write-offs and other restructuring-related expenses, adjusted EBIT was $52.9 million versus the prior period.

“Consumer segment sales were strong due to new accounts and market share gains, particularly in wood stains and automotive finishes,” stated Sullivan. “As previously discussed during our fiscal 2018 fourth-quarter conference call, we anticipated that the fiscal 2019 first quarter would be the high-water mark for margin erosion in the consumer segment. We responded with price increases late in the first quarter to help address this. In addition, legal costs accounted for nearly half of the EBIT decline for the quarter, with much of the remainder resulting from stepped up advertising to support recent market share gains.”

RPM’s specialty segment reported sales growth of 2.3%, to $192.8 million from $188.5 million in the fiscal 2018 first quarter. Organic growth contributed 2.0%, while acquisition growth was 0.4%. Foreign currency translation reduced sales by 0.1%. Specialty segment IBT was $27.8 million compared with $33.2 million in the prior-year period. EBIT was $27.7 million compared to $33.0 million in the fiscal 2018 first quarter. Adjusted EBIT, which excludes restructuring-related expenses, was $30.5 million in the fiscal 2019 first quarter.

“Specialty segment first-quarter results for the prior year were elevated by our water damage restoration businesses’ response to Hurricane Harvey, which created tougher year-over-year comparisons. Also, the first quarter of fiscal 2019 is the last quarter of negative comparisons related to the NatureSeal patent expiration last August,” Sullivan stated.

Cash Flow and Financial Position

During the fiscal 2019 first quarter, cash used from operations was $7.1 million compared to $26.1 million a year ago. Capital expenditures were $28.3 million in the quarter, compared to $17.5 million in the year-ago period.

Total debt at August 31, 2018 of $2.27 billion compares to $2.17 billion at May 31, 2018 and $2.12 billion at the end of last year’s first quarter. Net (of cash) debt-to-total capital was 56.2%, versus 54.7% at the end of last year’s first quarter and 54.2% at the end of the prior fiscal year. Total liquidity, including cash and long-term available credit, was $868.9 million, compared to $1.0 billion a year ago and $1.0 billion at May 31, 2018.

RPM Reports Fiscal 2019 First-Quarter Financial Results

October 3, 2018

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Business Outlook

“Our businesses will continue to aggressively pursue price increases to protect our gross profit margins in the face of continued raw material cost escalation. With asbestos trust payments now behind us, we are implementing strategic initiatives to enhance shareholder value through operational improvements and improved capital allocation. The current phase of our restructuring program is proceeding as scheduled with recently announced plant closings and leadership realignment. We will share a comprehensive update on our plan at an investor day on November 28, which will be webcast via the RPM website at www.rpminc.com,” stated Sullivan.

Webcast and Conference Call Information

Management will host a conference call to discuss the quarter’s results beginning at 10:00 a.m. EDT today. The call can be accessed by dialing 888-771-4371 or 847-585-4405 for international callers. Participants are asked to call the assigned number approximately 10 minutes before the conference call begins. The call, which will last approximately one hour, will be open to the public, but only financial analysts will be permitted to ask questions. The media and all other participants will be in a listen-only mode.

For those unable to listen to the live call, a replay will be available from approximately 12:30 p.m. EDT today until 11:59 p.m. EDT on October 10, 2018. The replay can be accessed by dialing 888-843-7419 or 630-652-3042 for international callers. The access code is 47510575. The call also will be available both live and for replay, and as a written transcript, via the RPM website at www.rpminc.com.

About RPM

RPM International Inc. owns subsidiaries that are world leaders in specialty coatings, sealants, building materials and related services across three segments. RPM’s industrial products include roofing systems, sealants, corrosion control coatings, flooring coatings and other construction chemicals. Industrial companies include Stonhard, Tremco, illbruck, Carboline, Flowcrete, Euclid Chemical and RPM Belgium Vandex. RPM’s consumer products are used by professionals and do-it-yourselfers for home maintenance and improvement and by hobbyists. Consumer brands include Rust-Oleum, DAP, Zinsser, Varathane and Testors. RPM’s specialty products include industrial cleaners, colorants, exterior finishes, specialty OEM coatings, edible coatings, restoration services equipment and specialty glazes for the pharmaceutical and food industries. Specialty segment companies include Day-Glo, Dryvit, RPM Wood Finishes, Mantrose-Haeuser, Legend Brands, Kop-Coat and TCI. Additional details can be found at www.rpminc.com and by following RPM on Twitter at www.twitter.com/RPMintl.

For more information, contact Russell L. Gordon, vice president and chief financial officer, at 330-273-5090 or rgordon@rpminc.com.

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RPM Reports Fiscal 2019 First-Quarter Financial Results

October 3, 2018

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Use of Non-GAAP Financial Information

To supplement the financial information presented in accordance with Generally Accepted Accounting Principles in the United States (“GAAP”) in this earnings release, we use EBIT, adjusted EBIT, adjusted net income and adjusted earnings per share, which are all non-GAAP financial measures. EBIT is defined as earnings (loss) before interest and taxes, with adjusted EBIT, adjusted net income and adjusted earnings per share provided for the purpose of adjusting for one-off items impacting revenues and/or expenses that are not considered by management to be indicative of ongoing operations. We evaluate the profit performance of our segments based on income before income taxes, but also look to EBIT as a performance evaluation measure because interest expense is essentially related to acquisitions, as opposed to segment operations. For that reason, we believe EBIT is also useful to investors as a metric in their investment decisions. EBIT should not be considered an alternative to, or more meaningful than, income before income taxes as determined in accordance with GAAP, since EBIT omits the impact of interest in determining operating performance, which represent items necessary to our continued operations, given our level of indebtedness. Nonetheless, EBIT is a key measure expected by and useful to our fixed income investors, rating agencies and the banking community all of whom believe, and we concur, that this measure is critical to the capital markets’ analysis of our segments’ core operating performance. We also evaluate EBIT because it is clear that movements in EBIT impact our ability to attract financing. Our underwriters and bankers consistently require inclusion of this measure in offering memoranda in conjunction with any debt underwriting or bank financing. EBIT may not be indicative of our historical operating results, nor is it meant to be predictive of potential future results. See the financial statement section of this earnings release for a reconciliation of EBIT to income before income taxes.

Forward-Looking Statements

This press release contains “forward-looking statements” relating to our business. These forward-looking statements, or other statements made by us, are made based on our expectations and beliefs concerning future events impacting us, and are subject to uncertainties and factors (including those specified below) which are difficult to predict and, in many instances, are beyond our control. As a result, our actual results could differ materially from those expressed in or implied by any such forward-looking statements. These uncertainties and factors include (a) global markets and general economic conditions, including uncertainties surrounding the volatility in financial markets, the availability of capital and the effect of changes in interest rates, and the viability of banks and other financial institutions; (b) the prices, supply and capacity of raw materials, including assorted pigments, resins, solvents and other natural gas- and oil-based materials; packaging, including plastic containers; and transportation services, including fuel surcharges; (c) continued growth in demand for our products; (d) legal, environmental and litigation risks inherent in our construction and chemicals businesses and risks related to the adequacy of our insurance coverage for such matters; (e) the effect of changes in interest rates; (f) the effect of fluctuations in currency exchange rates upon our foreign operations; (g) the effect of non-currency risks of investing in and conducting operations in foreign countries, including those relating to domestic and international political, social, economic and regulatory factors; (h) risks and uncertainties associated with our ongoing acquisition and divestiture activities; (i) risks related to the adequacy of our contingent liability reserves; and (j) other risks detailed in our filings with the Securities and Exchange Commission, including the risk factors set forth in our Annual Report on Form 10-K for the year ended May 31, 2018, as the same may be updated from time to time. We do not undertake any obligation to publicly update or revise any forward-looking statements to reflect future events, information or circumstances that arise after the date of this release.

CONSOLIDATED STATEMENTS OF INCOME    

IN THOUSANDS, EXCEPT PER SHARE DATA    

(Unaudited)    

SUPPLEMENTAL SEGMENT INFORMATION

IN THOUSANDS

(Unaudited)

SUPPLEMENTAL INFORMATION

RECONCILIATION OF “REPORTED” TO “ADJUSTED” AMOUNTS

(Unaudited)

CONSOLIDATED BALANCE SHEETS    

IN THOUSANDS    

(Unaudited)    

CONSOLIDATED STATEMENTS OF CASH FLOWS

IN THOUSANDS    

(Unaudited)