What does 6 12 roofing rafter mean? A 6/12 roofing rafter refers to a roof pitch where the roof rises 6 units vertically for every 12 units horizontally. How long can a 2×8 rafter span? Span length for a 2×8 rafter can be approximately 7 to 10 feet, depending on load and pitch.Ĭan a 2×6 rafter span 20 feet? A 2×6 rafter is unlikely to safely span 20 feet without additional support due to its limited load-bearing capacity. How far can a 2×8 rafter span 16 on center? Estimating around 10 to 12 feet, but this depends on various factors like wood species, load, and pitch. What is the spacing for rafters on a metal roof? Common rafter spacing for a metal roof is 24 inches on center, but this can vary based on factors like the type of metal roofing and local building codes. How far can a 2×10 rafter span without support? A rough estimation might be around 13 to 15 feet for a 2×10 rafter, but this depends on factors like the wood species, roof load, and pitch. For instance, for a 16-foot span with 24-inch spacing, you’d need 8 rafters. How do you calculate the number of rafters needed? Divide the span by the on-center spacing. How long is a 6 12 rafter per foot? A 6/12 rafter (which means the roof rises 6 units vertically for every 12 units horizontally) would have a slope angle of approximately 26.57 degrees. What size rafters do I need for a 16-foot span? For a 16-foot span, using 2×8 or 2×10 rafters is common, but the specific size would depend on factors like the roof pitch and load conditions. You’ll typically need to use a span/rafter sizing table or an online calculator that takes these factors into account. Our experts are standing by to take your call now to answer questions about our metal building roof purlins.How do you calculate rafter size? Rafter size is determined by factors like span, roof pitch, snow load, and the type of wood used. Pre-welded clips simplify construction and speed up the purlin framing process.Ĭall RHINO today at 940.383.9566 to learn more about the cost-effective RHINO Difference of low-rise construction. Moreover, RHINO rafters have factory-welded clips already installed for attaching purlins. The amount of lapping increases as the load increases. Consequently, all RHINO purlins overlap by design. The greater the amount of overlap between connecting purlins, the stronger the connection will be. However, at RHINO, we design our purlin systems for maximum strength. Some steel building companies provide purlin connections that butt flush against each other on the rafter. Taller purlins also allow room for increased insulation.įor coastal climates where high-humidity or salt corrosion poses problems, RHINO offers optional galvanized purlins, if desired.

If your design or local building codes demand extreme spans or snow loads, taller purlins may be required. Traditionally, RHINO steel buildings use 8” to 10” primed red-iron C-purlins and Z-purlins. The heavier the expected load is, the shorter the distance between the purlins. However, engineering determines the optimal roof purlin spacing. On a standard load, most designs call for purlin placement at five-foot intervals. The eave purlin marks the first purlin at the wall connection. When looking at the ends of the rails, the purlins shapes look like the letter “C” or the letter “Z.” These purlin styles get their names from their shapes. In general, metal roof purlins come in two varieties: C-purlins and Z-purlins. Consequently, a metal building system saves money on both building material and labor. Steel building purlins eliminate the need for oriented strand board (OSB) or plywood decking. It is also time-consuming to install, driving up labor costs. Wood framing employs decking to tie roof trusses together and support the roof. Thirdly, purlins add additional support between the spans of the individual framing bays.Īs an added bonus, metal roof purlins increase the structure’s resistance to strong winds.Secondly, purlins tie the rafters together, stabilizing and strengthening the structure’s rigid framing.Metal building roof purlins provide three structural functions: These structural supports run perpendicular across the rafter beams.Īlso known as “sheeting rails,” purlins create the roofing members of the secondary framing of a steel building. Purlins are an important component in a pre-engineered steel structural kit. What are purlins on a roof? Let’s get down to the basics of metal building roof purlins. What Purpose do Purlins Serve on a Steel Building?

Rafter spacing for metal roofing