In a log cabin with exposed beams, the tongue-and-groove roof decking boards will be visible from underneath, inside the house. The boards fit together much like the elements of a hardwood floor. These were secured by hand — with hammer and nails, rather than using a pneumatic framing nailer — since the hand nailing helps drive the tongue-and-groove elements together more tightly.
Once the first wood layer is down, cover it with 15-pound felt paper (Image 1). Tack the 15-pound felt paper into place with button-cap nails (Image 2); their wide tops prevent the nails from ripping the paper.
Expanded polystyrene insulation offers high R-value for enhanced insulation. Wood lathing strips laid across the foam insulation (Image 1) add rigidity to the roof structure and provide an air channel for ventilation of the roof underneath the meal surface. Secure the lathing and foam red to the roof substrate with extra-long screws (Image 2).
Secure a layer of OSB plywood on top of the lathing, followed by a layer of thicker (30-pound) felt paper. The second layer of felt paper adds more resistance to water penetration.
Finally, install the metal panels (Image 1), placing metal closures on the top and sides of the roof structure to hold the panels in place. Secure them with clip fasteners (Image 2), not screws, penetrating the metal panels themselves. The panels that make up the roof fit together like pieces of a puzzle — snug and tight.