Even though truss-designed roofs are prevalent throughout most of the residential construction industry, there are regions where building with steel frame roofs is still common. There are two common ways to frame the roof of a house: with premanufactured trusses, or with rafters and ceiling joists, commonly called stick framing.
While support roofs are the most popular construction style today, there are regions of the country where builders still prefer steel-frame roofing. There are several reasons for this. One of the most common is that with steel building frame components, it’s easier to customize the roofline. Builders sometimes also prefer this construction method when they want to provide a large attic space or high, vaulted ceilings.
However, building a framed roof is not always easy. Whether it’s because of the growing size of houses, or because roofs are getting more complicated, the code requirements for stick framing roofs have become more complex over the years, too. Meeting current IRC roof framing requirements means builders are really constructing very simple triangles using the rafters and ceiling joists because triangles are known to be the most stable shape.
In order to maintain the triangle shape, there are specific requirements for how to fasten the corners of the triangle together. Most importantly, the bottom of each triangle must be fastened securely to the rafters on each end and must continue across the entire width of the ceiling so they keep the ends of the rafters from spreading out when loaded.