关于屋面的选择###屋面的选择和建筑规范屋面瓦粘土和混凝土瓦屋顶可以安装在坚固的护板或间距的护板上，在坡度为2.5/12或更高的屋顶。坡度小于4/12的屋顶需要双层覆盖衬垫(905.3.3.1);屋顶倾斜在4/12和更大需要一层(905.3.3.2)。贴瓦方法因气候条件、屋顶坡度、衬砌系统和瓦类型而异。有关正确的附件方法，请参阅IRC第905.3.7节和表905.3.7。在墙壁和垂直穿透处应设置闪蒸和反闪蒸。山谷闪光必须至少是26号规格的“W”型材，G90镀锌板，并从山谷中心线(905.3.8)向两个方向延伸11英寸。石板岩载于2006年IRC第905.6节。板岩必须用两颗钉子安装在至少4/12间距(905.6.2)的实心护套屋顶上，下面有ASTM D 226类型1衬垫(905.6.3)。有冰坝历史的屋顶区域必须用胶结的两层下垫层，或者用自粘的沥青膜从屋顶边缘延伸到建筑物外墙外24英寸。 Head lap requirements vary with roof pitch and can be found in Table 905.6.5. The minimum standard for valley flashing is 15-inch, G90 galvanized steel of .0179-inch thickness (905.6.6). Asphalt roof shingles Asphalt shingles (Section 905) must be installed on solid sheathed roofs of at least 2/12 pitch with 12-gauge roofing nails long enough to go through the shingle and penetrate the roof deck 3/4 of an inch. Roofs under 4/12 pitch require two layers of underlayment; roofs 4/12 and steeper require one layer. Roof areas with a history of ice damming must have two layers of underlayment cemented together or a self-adhering, bituminous membrane extending from the roof edge to 24 inches…