LP and Ainsworth Agree to Extend Outside Date for Completion of Previously Announced Plan of Arrangement

NASHVILLE, Tenn. and VANCOUVER, B.C. (April 18, 2014) – Louisiana-Pacific Corporation (NYSE: LPX) (“LP”) and Ainsworth Lumber Co. Ltd. (TSX: ANS) (“Ainsworth”) announced today that they have agreed to extend the outside date for completion of the previously announced plan of arrangement (the “Arrangement”) under the Business Corporations Act (British Columbia) involving the proposed acquisition by LP of all the outstanding common shares of Ainsworth, fromApril 18 to June 2, 2014.

The extension comes as a result of continued discussions with each of the Canadian Competition Bureau (the “CCB”) and the Antitrust Division of the U.S. Department of Justice (the “DOJ”) as both Ainsworth and LP continue to work with the CCB and the DOJ as they conduct their reviews. The Arrangement agreement permits either party to further extend the outside date for an additional 45 day period if required to obtain certain regulatory approvals.

The closing of the Arrangement remains subject to a number of conditions, including the expiration or termination of the waiting period under the HSR Act and the receipt of other regulatory approvals and clearances including under the Canadian Competition Act.

Further information about the Arrangement is set out in Ainsworth’s management proxy circular dated September 24, 2013, which is available under Ainsworth’s profile on www.sedar.com and under LP’s profile at www.sec.gov.

Cautionary Statement Regarding Forward-Looking Information

Forward-looking information provided in this news release relating to Ainsworth’s and LP’s expectations regarding the completion of the Arrangement and Ainsworth’s and LP’s future prospects and financial position are forward-looking information pursuant to National Instrument 51-102 promulgated by the Canadian Securities Administrators and the Private Securities Litigation Reform Act of 1995. Ainsworth and LP believe that expectations reflected in such information are reasonable, but no assurance is given that such expectations will be correct. Forward-looking information is based on Ainsworth’s and LP’s beliefs and assumptions based on information available at the time the assumptions were made and on their managements’ experience and perceptions of historical trends, current conditions and expected further developments as well as other factors deemed appropriate in the circumstances. Investors are cautioned that there are risks and uncertainties related to such forward-looking information (including the satisfaction of closing conditions for the Arrangement) and actual results may vary. Important factors that could cause actual results to differ materially from those expressed or implied by such forward looking information include, without limitation, factors detailed from time to time in Ainsworth’s or LP’s periodic reports filed with the Canadian SecuritiesAdministrators, the U.S. Securities and Exchange Commission or other regulatory authorities. The forward-looking information is made as of the date of this news release and neither Ainsworth nor LP assumes any obligation to update or revise them to reflect new events or circumstances, except as explicitly required by applicable securities laws.

About Ainsworth - Ainsworth Lumber Co. Ltd. is a leading manufacturer and marketer of oriented strand board (“OSB”) with a focus on value-added specialty products for markets in North America and Asia. Ainsworth’s four OSB manufacturing facilities, located in Alberta,British Columbia and Ontario, have a combined annual capacity of 2.5 billion square feet (3/8-inch basis). Ainsworth is a publicly traded company listed on the Toronto Stock Exchange under the symbol ANS. For more information, visit www.ainsworthengineered.com. The website at www.ainsworthengineered.com (the “Ainsworth Website”) is operated by Ainsworth, and LP disclaims any responsibility for the accuracy or completeness of any information contained on the Ainsworth Website or on any website linked to the Ainsworth website. The website at www.lpcorp.com (the “LP Website”) is operated by LP, and Ainsworth disclaims any responsibility for the accuracy or completeness of any information contained on the LP Website or on any website linked to the LP website.

About LP Building Solutions - As a leader in high-performance building solutions, Louisiana-Pacific Corporation (LP Building Solutions, NYSE: LPX) manufactures engineered wood building products that meet the demands of builders worldwide. Its extensive offerings include innovative and dependable building products and accessories, such as LP^® SmartSide^® Trim & Siding, LP Structural Solutions portfolio (LP WeatherLogic^® Air & Water Barrier, LP Legacy^® Premium Sub-Flooring, LP^® TechShield^® Radiant Barrier, LP^® FlameBlock^® Fire-Rated Sheathing and more), oriented strand board (OSB), LP^® TopNotch^® Sub-Flooring, LP^® Outdoor Building Solutions^®, and LP Elements^® Performance Fencing. In addition to product solutions, LP provides industry-leading service and warranties. Since its founding in 1972, LP has been Building a Better World^™ by helping customers construct beautiful, durable homes. Headquartered in Nashville, Tennessee, LP operates 26 plants across the U.S., Canada, Chile and Brazil. For more information, visit LPCorp.com.