#Spacing rafters for metal roof code

When compared to rafters with wider spacing, 16' spacing indicates the use of a smaller lumber size and a lower wood grade. Six rafters are placed every 8' when 16' spacing is used. 16” Spacing or 24” Spacing for Rafters?Ī rafter spacing of 16' is quite common in oriented strand board and plywood roofs. If the rafters are heavier, then 16” spacing is provided for rafters used in pergolas. Spacings of 12' and 16' are most commonly used.Ī spacing of 12' is used when the dead weight of the rafters is not heavy enough to cause problems. The standard spacing provided in pergolas ranges between 12” to 20”. Rafter spacing in pergolas varies with its dimensions and aesthetics. You need to fasten the metal plates to the roof rafters to provide support. While the manufacturer determines the metal panel width, the length depends upon the ridge-to-eave measurement.

The common spacing for the rafters used in metal roofing is 16” or 24” in the center. Metal roofing for houses commonly uses aluminum or steel sheets. To determine the final size of a rafter, consider various factors such as loads, wood species, wood grade, the slope of a roof, and the location of the rafter. The size of a rafter is a measure of its width and depth, and the most common rafter sizes are 2x4, 2圆, 2x8, 2x10, and 2x12.Ģx4 rafters are more commonly used in residential construction. You can also calculate the rafter span with the American Wood Council's online calculator. Note that these values are for unattached ceilings with a 180-degree deflection. These tables are for dead loads of 10 psf and live loads of 20 psf with unattached ceilings. Once the rafter spacing is determined, the number of total rafters and their span can be calculated.Ī greater distance between two rafters allows them to span a shorter length.Ī Douglas fir-larch, SS grade 2圆 rafter spans 18’ with 12” spacing, while it only spans 14’-4” with 24” spacing. Rafter spacing is an essential parameter of roof design.

#Spacing rafters for metal roof code

The typical on-center spacing provided in the International Residential Code (IRC) 2021 includes spacings of 12”, 16”, 19.2”, and 24”. Rafter spacing is the distance between the centers of two consecutive parallel rafters. Roof Rafter Spacing, Span, and Sizing Requirements Roof Rafter Configuration.

For a particular span, rafter spacing distance can vary based on the species of lumber, grade, and load conditions. The International Residential Code (IRC) 2021 specifies roof rafter spacings of 12', 16', 19.2', and 24'.The common sizes for rafters include 2x4, 2圆, 2x8, 2x10, and 2x12. Rafters act as support for roofs of houses, sheds, porches, cabins, and garages.