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.
Patio roof made with rafters.
Then force the rafter s tip snugly against the house wall.
It is almost similar to the first method but to make the patio roof a little bit higher you will need to remove the house gutter and place the back channel a bit higher.
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.
Your top chords can protrude beyond the bottom chord anywhere from 1 3 feet 0 30 0 91 m.
Using a block of wood as a ruler mark the ends for cutting.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
Rafters are placed on 24 centers and attached to the beams and settle joists are attached as needed image 1.
If you think you d prefer an overhang style truss adjust the measurements for your top chords accordingly.
A pergola is a non traditional style roof in that it s open and provides filtered shade than protection from the elements.
These trusses the meet building code criteria as specified by structural building components of america sbca and the truss plate institute tpi.
Pre manufactured stock trusses are constructed with spruce pine fir spf or southern yellow pine syp lumber.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
Attach 2x6 rafters to the house with joist hangers and or supported by the ledger board.
Plan your pergola carefully.
On some roof trusses the 2 top chords extend down over the edges of the bottom chord creating a built in overhang.
If necessary use a sliding bevel to determine angles needed where the rafters will meet the ledger board.
To cut sloping rafters for a house attached patio roof lay a rafter board so it rests on its edge on both the ledger and the beam parallel to the ledger.
The tables below give maximum spans for rafters and beams.
The figures are based on quality materials.
Make the patio roof a little bit higher.
Because the gutter is removed you will need to install transfer flashing from the roof of the house to the patio.
This freestanding structure is supported by posts or columns and the roof is made up of evenly spaced slatted beams.
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.
If you re building rafters and aren t sure where to start when determining the length of your lumber you re in the right place our rafter stock size calculator shows you how long your rafters should be so you ll know what you need in terms of framing lumber dimensional lumber studs and more.
Just enter the dimensions of the roof rise and run to get started.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
