Abstract: A support mat, such as a mat suitable for supporting heavy construction equipment, includes a plurality of billets fastened together, each of the billets being made of a plurality of individual wood laminations adhesively bonded to each other. The billets comprise a plurality of vertically oriented individual wood laminations. The plurality of individual wood laminations has wide faces oriented parallel to a direction of a load applied to the support mat. Each billet has outboard laminations and the wide faces of the outboard laminations of each billet define a wide face of the billet. An expansion pad is disposed between the wide faces of adjacent billets.