If not the patio roof only bears it s own weight and the block stiffens the joists dramatically.
How far apart do you put boards for porch roof.
In this example the section of roof is 20 feet wide and 14 feet from the fascia to the peak.
The higher the snow load the closer the purlin spacing required.
Another thing you will need to do is brace the second gable end on the roof and secure it.
If so you may want to go to 2 x 8.
Too high a snow load means the purlins fail regardless of how close together you put them because a 2 4 or 2 6 flat can only span a certain distance between trusses as snow loads increase.
Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter.
However you will want to have boards that can be used as braces for the tresses.
When you cut the rafters you ll need to make 3 separate cuts.
The best size board to use is 1x4 pieces that are 10 feet long.
This translates to seven rows of strips 20 feet long spaced two feet apart or 140 lineal feet of.
Do you get a massive amount of snow.
The other issue is the building code.
You do not have to brace all the trusses just plumb the second gable.
The ridge cut also called the plumb cut at the top of the rafter the birdsmouth cut which itself comprises 2 different cuts where the rafter meets the building s wall and the tail cut at the base.
The smallest beams for patio covers are typically 4 by 6.
That s a long span.
The common 4 on center design is suitable for snow loads up to 60 for most applications.