N LOG HOMES Leaders i Excellence PRODUCT SPECIFICATIONS For Timber Si din Description: Kiln-dried SPF, # 2 grade or better, milled to finished size. Size: 1 7/16” thick at curvature, 917 tall. Details: 7/16” groove, 3/8” tongue. Coverage: 8 5/8” wall coverage. Conversion Factor: 1.39 lineal feet = 1 square foot. To convert wall square footage to lineal feet, multiply the length of the wall by the height of the wall to find the total square footage.