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.
Sizing roof supports.
If one side of the roof is supported by the house and the other side is supported by the beam divide the total load by two as the beam is only supporting half of the roof.
There are a few things to know before erecting a protective roof.
This sizing guide for roof rafters will help determine what you need for your small project.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
Beams can be solid lumber or be built from lengths of 2 by lumber nailed together with 1 2 inch pressure treated plywood spacers in between this forms a 3 1 2 inch thick beam that is equal to the width of a 4 by post.
If our example roof has only one beam it must carry half of the total load or 4 000 pounds.
Maximum rafter spans for a patio roof.
Wood beam calculator american wood council website rafter and joist span faq.
While i know your idea seems logical and it might work consulting with an architect or engineer is the only way to know for sure.
If there is also a beam in the middle of the roof divide the total load by three.
Ridge beam sizing is based on the span of the beam between supports and the amount of roof load supported by the beam.
A roof on a treasured deck can open up more possibilities for enjoying the space throughout the year.
Raised floor homes look great and protect homeowners against risks from flooding and subsiding soils.
This article excerpts from provides copies of roof framing suggestions from canadian building codes and the cmhc wood frame house construction guide.
The sizes of your porch roof framing members their spacing the type of.
For heavy roofs or in.
For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine.
Roof framing suggestions canadian guidelines.
The 1 grade.
Framing any roof but particularly a gable roof low slope roof and cathedral ceilign roofs requires collar ties rafter ties and possibly a structural ridge beam to support the roof and to.
Ridge boards can only be used in roofs with slopes from 3 in 12 up to 12 in 12.
There are several variables to consider when determining the proper rafter size.
A ridge board is a non structural member that serves as a prop for opposing rafters to rest against and connect to.
The lengths and sizes of joists vary depending on the species and quality of the lumber used.
Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter.
