sealants and institutional roofing systems used in building protection, maintenance and weatherproofing applications marketed under our TREMCO, REPUBLIC, VULKEM and DYMERIC brand names

Exhibit 10.15.6

SIXTH AMENDMENT TO THE
RPM INTERNATIONAL INC. 1997 RESTRICTED STOCK PLAN

     THIS SIXTH AMENDMENT to the RPM International Inc. 1997 Restricted Stock Plan is executed by RPM International Inc. (hereinafter referred to as the “Company”) as of the date set forth below.

WITNESSETH:

     WHEREAS, the Company adopted and maintains the RPM International Inc. 1997 Restricted Stock Plan (hereinafter referred to as the “Plan”) for the benefit of certain of its employees and certain employees of the Company’s subsidiaries; and

     WHEREAS, the Company reserved the right, pursuant to Section 8 of the Plan, to make certain amendments thereto; and

     WHEREAS, it is the desire of the Company to amend the Plan so that, upon lapse of restrictions on stock awarded thereunder, the Company or the escrow agent shall automatically sell the number of shares necessary to generate sufficient proceeds to satisfy the grantee’s minimum tax liability arising from the lapse of restrictions;

     NOW, THEREFORE, pursuant to Section 8 of the Plan and effective as of the date hereof, the Company hereby amends the Plan as follows:

     1. Section 5.1 of the Plan is hereby amended by the deletion of Section 5.1 in its entirety and the substitution in lieu thereof of a new Section 5.1 to read as follows:

     “5.1 The Shares shall not be sold, transferred or otherwise disposed of and shall not be pledged or otherwise hypothecated (and any such sale, transfer or other disposition, pledge or other hypothecation being hereinafter referred to as “to dispose of” or a “disposition”) until the earliest of (a) the later of either the employee’s termination of

employment with the Company and any of its subsidiaries or the lapse of the right of the Company to a return of such Shares pursuant to Section 5.2 below; (b) a change in control that occurs with respect to the Company; or (c) the termination of the Plan. Notwithstanding the foregoing, but subject to the terms, conditions and restrictions specified under this Plan, after the date that a participant’s Shares become nonforfeitable in accordance with Article 5 or Article 6, and provided that the participant has not surrendered the Shares in accordance with Section 11.3, the Company or the escrow agent (as the case may be) shall sell the fewest number of such Shares with respect to which restrictions have lapsed necessary for the proceeds of such sale to equal (or exceed by not more than the actual sale price of a single Share) the participant’s minimum tax liability determined by multiplying (A) the aggregate minimum marginal federal and applicable state and local income tax rates on the date of the lapse of restrictions; by (B) the total number of Shares with respect to which restrictions have lapsed. The Company or the escrow agent (as the case may be) shall withhold the proceeds of such sale for purposes of satisfying the participant’s federal, state and local income taxes resulting from the lapse of restrictions. The Company or the escrow agent (as the case may be) shall deliver the proceeds of the sale of Shares to the Internal Revenue Service and/or other taxing authority in satisfaction of the participant’s tax liability arising from the lapse of restrictions. The participant shall provide the Committee, the Company and/or the escrow agent with such stock powers and additional information or documents as may be necessary for the Committee, the Company and/or the escrow agent to discharge their obligations under this Section.”

     IN WITNESS WHEREOF, RPM International Inc., by its officer duly authorized, has caused this Sixth Amendment to the RPM International Inc. 1997 Restricted Stock Plan to be signed effective as of September 1, 2006.

		RPM INTERNATIONAL INC.
		By:		/s/ Ronald A. Rice
				Ronald A. Rice
		Its:		Senior Vice President — Administration