These plans for a gambrel roof shed will help you construct a barn style structure in your yard in no time. the detailed rafter template diagrams help you construct the roof quickly with minimum cuts.. 12'x16' barn shed shed materials materials shopping list pt = pressure treated note: loft materials not included here. material n r l l l l s f s c s y h e 2x4x8 10 15 15 10 2 6 58 2x4x8 pt 0 2x4x10 22 22 2x4x10 pt 0 2x4x12 3 3 6 2x4x12 pt 0 2x4x14 0 2x4x16 0 3 3 6 2x4x16 pt 0 2x6x8 0 2x6x8 pt 0 2x6x10 0. We offer small sheds to large sheds and offer a wide range of product sizes - amazingly low prices plus free uk delivery on all of our garden buildings. xl workshop (9) 9 products.