Porch Roof Rafter Spacing

We show you the steps involved and calculations required for buildng a roof for your porch or constructing one over your deck or patio.

Porch roof rafter spacing.

In other words the maximum distance it can cover without support from posts. Spacing in exterior exposure. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter.

However if the spacing is too wide the patio cover s beams will bow under the weight of the joists and roof covering materials. The determining factor of post spacing is the allowable span of your beams. 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 spacing is based on the width of the metal roofing panels.

The spacing between rafters in a given building is part of the engineering calculations that determine the required structure of the roof. This sizing guide for roof rafters will help determine what you need for your small project. For standard shed roof rafter spacing see rafter span chart. There are several variables to consider when determining the proper rafter size.

Maximum rafter spans for a patio roof. Span calculator for wood joists and rafters also available for the. Building a porch roof requires basic carpentry and porch roof framing knowledge. If you get premium kiln dried lumber then you could span 10 5 with the same size of lumber and.

Rafters must be strong enough to hold the roof sheathing and the shingles. For instance 2 grade 2x4s at 16 on center will span just over 9. 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. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.

Other relevant factors include the type of wood being used for the rafters the size of the rafters and the load that the rafters need to support. We show you how both a typical rafter style porch and truss roof area constructed. Wider panels allow for greater spacing between rafters. A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel.