This promotion is intended for participation in the contiguous United States and the District of Columbia (“D.C.”) only and shall be construed and evaluated according to the laws of the United States. Do not enter if you are not 18 years of age or older and a legal resident of and located in one of the eligible states or D.C.

SECUROCK ULTIMATE RACE EXPERIENCE!

Official Rules

NO PURCHASE NECESSARY TO PARTICIPATE. A PURCHASE WILL NOT INCREASE YOUR CHANCES OF WINNING. VOID IN ALASKA, HAWAII AND OUTSIDE THE REMAINING STATES, AND THE DISTRICT OF COLUMBIA (D.C.), AND WHEREVER PROHIBITED. Securock Ultimate Race Experience (“Sweepstakes”) is open only to legal residents of the contiguous United States and D.C. who are 18 years of age or older and are employed as a Commercial Roofing Contractor doing business in the contiguous United States or D.C. (see further restrictions in Rule 4 below). NOT OPEN TO THE GENERAL PUBLIC. Sweepstakes begins at 12:00:01 AM Central Time (“CT”) on 7/13/07 and ends at 11:59:59 PM (CT) on 12/31/07 (“Promotion Period”). 1. TO ENTER: Go to www.usg.com/securock, access the appropriate Sweepstakes entry page, and follow the on-screen instructions to enter the Sweepstakes. All entries must be received by 11:59:59 PM (CT) on 12/31/07. Limit one (1) entry per person/email address/household, during the Promotion Period. 2. PRIZE WINNER SELECTION: Winner will be selected in a random drawing from among all eligible entries received, on or about 1/7/08, by Promotion Activators, Inc., an independent judging organization whose decisions shall be final on all matters related to this Sweepstakes. Odds of winning depend on the total number of eligible entries received in accordance with these Official Rules. 3. PRIZE: One (1) Grand Prize will be awarded consisting of a trip for two (2) people to Daytona Beach, Florida to attend the DAYTONA 500® Race scheduled to occur on February 17, 2008 at Daytona International Speedway®. Grand Prize includes round-trip, coach class air transportation for two (2) from an airport near winner’s home within the U.S. to either Daytona Beach or Orlando, Florida or to another location within seventy (70) miles of Daytona Beach (flight destination and/or point of departure within Florida and exact travel dates will be determined by Sponsor in its sole discretion); one(1) double occupancy standard hotel room for two (2) nights; ground transportation to and from the hotel and the Daytona International Speedway® on day of race; ground transportation to and from the airport and hotel in FL; two (2) race credentials for the DAYTONA 500® Race on 2/17/08; a chance for the winner only to have a Pit and Garage tour and Meet & Greet with a race driver, a Race Scanner, a Duffel Bag, a Polo Shirt, Lanyard and Credential Holder and Earplugs. Approximate retail value: up to $2,500, depending upon winner’s point of travel origin. All expenses not specified herein, including but not limited to, meals, transportation (except as specified herein), incidental hotel expenses, taxes and gratuities are the sole responsibility of the winner. Actual value may vary depending on point of origin, destination city, time of travel and airfare fluctuations. Any difference between any stated value and actual value will not be awarded. Winner and guest must travel on the same itinerary, and on the dates and times specified by Sponsor or prize will be forfeited in its entirety. Winner and guest must comply with all security requirements. If winner is an eligible minor in his/her jurisdiction of residence he/she must travel with his/her parent/legal guardian. No additional travel expenses or any other aspects of the Grand Prize will be awarded should Guest's parent or legal guardian be required to accompany a Guest. All travel and accommodations may be subject to change, restrictions, and black out periods. If, for any reason outside the control of the Sponsor, the DAYTONA 500® Race or the Meet & Greet are postponed or cancelled, the Sponsor will have no further obligation other than to award the remainder of the prize. Winner will be responsible for all federal, state and/or other income taxes on prize. Prize is non-transferable and no substitutions or cash redemptions will be made except as provided herein or at Sponsor’s sole discretion. Winner must comply with all Sweepstakes rules as published. Winner will be notified by overnight mail and will be required to execute and return an affidavit of eligibility and liability/publicity release (where permitted) within seven (7) days of notification. Travel companion of Grand Prize winner (or his/her parent or legal guardian if companion is a minor) must complete and return a liability/publicity release prior to departure. If a winner is a minor in his/her state of residence, the prize will be awarded on winner’s behalf to a parent/legal guardian of winner who must execute and return all required documents as noted previously in these rules. Failure of a winner (or his/her parent or legal guardian) to comply with the above prize claim requirements for any reason, or the return of any prize notification or prize as undeliverable, or the determination that the winner is ineligible to receive a prize, will result in forfeiture of the prize. If a winner is found to be in violation of any of these rules, he/she will be required to forfeit his/her prize, or, at Sponsor’s discretion, to reimburse Sponsor for the stated value of the prize if such violation is found after the prize has been used. If a prize is forfeited for any reason, an alternate winner will be drawn at random from the remaining eligible entries and awarded the prize, time permitting. Unless otherwise noted, allow approximately 4 weeks for shipment of prize items (Duffel Bag, Polo Shirt, Lanyard and Credential Holder and Earplugs) following completion of notification process and verification of eligibility. Sponsor reserves the right to substitute prize (or any element thereof) for one of equal or greater value if the prize (or any element thereof) should become unavailable for any reason. Any and all guarantees and warranties for merchandise prizes are subject to the manufacturer’s terms and conditions and winners agree to look solely to such manufacturers for any such warranty or guarantee claim. 4. ELIGIBILITY RESTRICTIONS: Employees of Sponsor, its parent company, affiliates, subsidiaries, agents, retailers, advertising, promotion, and judging agencies and members of the immediate families or households of any of the above are NOT eligible to participate. For purposes of these rules, “immediate families” means spouse, parents or legal guardians, siblings, children, step-parents, step-siblings, step-children, and the spouses of each of the foregoing. 5. GENERAL: Prize must be accepted as awarded. Except where prohibited by law, acceptance of a prize constitutes permission to use winner's name, hometown, likeness, photograph, statements made by winner about the promotion and/or prize information for advertising, trade and/or publicity purposes in commerce and in all media worldwide without limitation and without additional compensation. BY PARTICIPATING IN THIS SWEEPSTAKES, ENTRANTS AGREE TO BE BOUND BY THE OFFICIAL RULES AND THE DECISIONS OF THE JUDGES AND TO RELEASE AND HOLD HARMLESS SPONSOR, ITS RELATED COMPANIES, AND EACH OF THEIR RESPECTIVE SUBSIDIARIES, AFFILIATES, ADVERTISING, PROMOTION, JUDGING AGENCIES, DIRECTORS, OFFICERS, PRIZE SUPPLIERS, EMPLOYEES, AND AGENTS FROM AND AGAINST ANY LIABILITY WHATSOEVER FOR ANY CLAIMS, COSTS, INJURIES, LOSSES OR DAMAGES OF ANY KIND ARISING OUT OF OR IN CONNECTION WITH PARTICIPATION IN THE SWEEPSTAKES, OR THE DOWNLOADING OR ACCESSING OF ENTRY MATERIALS, OR THE ACCEPTANCE, POSSESSION OR USE/MISUSE OF ANY PRIZE AWARDED HEREIN, ANY SERVICES PROVIDED BY PARTIES OTHER THAN SPONSOR IN CONNECTION WITH THE PRIZE AWARDED, OR PARTICIPATION IN ANY PRIZE-RELATED ACTIVITY (INCLUDING, WITHOUT LIMITATION, CLAIMS, COSTS, INJURIES, LOSSES OR DAMAGES RELATED TO PERSONAL INJURIES, DEATH, DAMAGE TO, LOSS OR DESTRUCTION OF PROPERTY, RIGHTS OF PUBLICITY OR PRIVACY, DEFAMATION OR PORTRAYAL IN A FALSE LIGHT). BY ACCEPTING THE GRAND PRIZE, THE WINNER (OR HIS/HER PARENT OR LEGAL GUARDIAN) ACKNOWLEDGES THE INHERENTLY DANGEROUS NATURE OF AND RISKS INVOLVED IN TRAVEL AND ATTENDING A NASCAR RACE, INCLUDING BUT NOT LIMITED TO PERSONAL INJURY AND OR DEATH, AND AGREES TO SIGN A RELEASE TO THAT EFFECT. 6. INTERNET: The use of any automated launching or entry software or any other mechanical or electronic means that permits the participant to automatically enter repeatedly is prohibited. Any person who uses or attempts to use such means to enter the Sweepstakes will be disqualified from participation in the Sweepstakes and will be ineligible to receive a prize. If for any reason this Sweepstakes is not capable of running as planned due to infection by computer virus, bugs, tampering, unauthorized intervention, fraud, technical failures, or any other causes beyond the control of Sponsor which corrupt or affect the administration, security, fairness, integrity, or proper conduct of this Sweepstakes, Sponsor reserves the right at its sole discretion, to disqualify any individual who tampers with the entry process, and to cancel, terminate, modify or suspend the Sweepstakes. In the event that the Sweepstakes is cancelled or terminated prior to the stated end date, prize will be awarded in a random drawing from among all eligible, non-suspect, entries received prior to the time of the action or event warranting such cancellation/termination. Proof of entering information on Sponsor’s website is not considered proof of delivery or receipt by Sponsor. Sponsor assumes no responsibility for any error, omission, interruption, deletion, defect, delay in operation or transmission, communications line failure, theft or destruction or unauthorized access to, or alteration of, entries. Sponsor is not responsible for electronic transmissions or entries that are lost, late, stolen, incomplete, illegible, damaged, garbled, destroyed or misdirected, or for any problems or technical malfunction of any telephone network or telephone lines, computer on-line systems, servers, or providers, computer equipment, software, failure of any e-mail or entry to be received by Sponsor on account of technical problems, human error or traffic congestion on the Internet or at any Web site, or any combination thereof, or for any injury or damage to participant's or any other person's computer relating to or resulting from participation in this Sweepstakes or the downloading or accessing of any materials in this Sweepstakes. Sponsor is further not responsible for incorrect or inaccurate entry information whether caused by Internet users or by any of the equipment or programming associated with or utilized in the Sweepstakes or by any technical or human error, which may occur in the transmission, receipt or processing of entries. All incomplete or otherwise non-conforming entries will be disqualified. CAUTION: ANY ATTEMPT TO DELIBERATELY DAMAGE ANY WEB SITE OR UNDERMINE THE LEGITIMATE OPERATION OF THE SWEEPSTAKES MAY BE A VIOLATION OF CRIMINAL AND CIVIL LAWS AND SHOULD SUCH AN ATTEMPT BE MADE, SPONSOR RESERVES THE RIGHT TO DISQUALIFY AND SEEK DAMAGES OR OTHER REMEDIES FROM ANY SUCH PERSON (S) RESPONSIBLE FOR THE ATTEMPT TO THE FULLEST EXTENT PERMITTED BY LAW. In the event of a dispute as to the identity of a potential winner based on an e-mail address, the potential winning entry will be declared made by the authorized account holder of the e-mail address submitted at time of entry, provided such person meets the eligibility requirements of these Official Rules. "Authorized account holder" is defined as the natural person who is assigned to an e-mail address by an Internet access provider, on-line service provider or other organization (e.g., business, educational, institution, etc.) that is responsible for assigning e-mail addresses for the domain associated with the submitted e-mail address. 7. WINNER’S NAME: For the prize winner’s name, available after 12/31/07, send a self-addressed stamped envelope to: Securock Ulitimate Race Experience Winners, 1851 Elmdale, Glenview, IL 60026 by 3/31/08.

Sponsor: USG Corporation, 550 W. Adams St., Chicago, IL 60661-3676.

® Securock, DAYTONA, DAYTONA 500, Daytona International Speedway are registered trademarks and are used with permission.