Rafter Spacing For Metal Roof

It is always better to have a large rafter rather than be concerned with a sagging roof.

Rafter spacing for metal roof. Common spacing for trusses on this type of building is often between 2 and 4 feet but trusses built with advanced designs may allow spacing as great as 8 or 12 feet. An engineer will use a load chart in order to determine the spacing between metal purlins. Do not use pressure treat wood for the purlins it will eat up the metal roofing and screws. A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel.

The same concept holds true for roof trusses. Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. You have to take the width of your roofing panel into the considerations.

An essential part of planning a patio roof or gazebo project is determining the number size and spacing of rafters beams and posts according to the loads they will carry. Once the purlin spacing is determined then the metal roofing panels are typically attached to every line of purlins. Wider panels allow for greater spacing between rafters. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.

The most common measurement used for rafter spacing is either 16 or 24 inches. 2 4 rafters can span up to 7. Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. Most roof framing is 24 on center and you can still build sheds up to 14 with 2 4 rafters at 24 on center.

Spacing your 2 4 shed rafters at 24 on center limits the width of your roof. For light load roofs 24 o c. Rafter spacing is based on the width of the metal roofing panels. Keep it at 24.

Never seen anyone use 2 x 4 s always 1 x 4 s. Screw line spacing for metal roofing over metal purlins this will depend upon the type of panel that is used and the thickness of the steel. For heavy loads 2x4s can span up to 5. So the space between rafters can be greater without reducing the maximum span.