Rafter Spacing For Slate Roof

Surveyors span tables for designing roof rafters.

Rafter spacing for slate roof.

Rafters must be strong enough to hold the roof sheathing and the shingles. But they do tend to space rafters in one of several industry standard increments typically. A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel. For pitched roofs flat roofs and ceiling joists.

As a general rule roofs that have a high human occupancy rate should be framed with rafters every 16 structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. Other imposed loads roof snow load and short term point load altitude not exceeding 100m. Rafter and roof joist spacing is only one part of a complex roof design that works together to form a structure that meets building codes and can hold up the weight of the roof and roof load. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.

Roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16 size of rafters in mm 400mm 450mm 600mm. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. The boards creating the slope of the roof are wider than lumber used to build trusses 2x8s 2x10s and 2x12s are most common in rafters vs. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

Rafter spacing is based on the width of the metal roofing panels. Builders aren t bound by standard rafter spacing measurements. In finished space insulation is placed between the rafter boards and drywall or other material is fastened to the face. 0 75 kn m snow load 0 9 kn.

This is the distance between rafter centres. Usually 400 450 or 600mm but any value can be used up to 610mm max. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. Rafter boards are fastened to the ridge board at the peak and the top plate where they join the wall.