In this case the framer used 9 8d nails on each side of splice which is adequate in this case.
2x4 rafters to 2x8 floor joists.
A 9 2 2x4 2 2x6 2 2x6 2 2x6 2 2x8 2 2x10 2 2x10 2 2x12 2 2x12 n 10.
This a rough guideline.
Floor beam table.
Get free shipping on qualified 2x4 joist hangers or buy online pick up in store today in the building materials department.
While every effort has been made to insure the accuracy of the information presented and special effort has been made to assure that the information reflects the state of the art neither the west coast lumber inspection bureau the american wood council nor its members assume any responsibility for any particular design prepared from this online span calculator.
In this case the framer just needed a longer rafter.
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.
Also available for the android os.
The heavier the load the closer together the.
However when running spf 2 6 floor joists into the floor joist calculator referenced above you get a maximum span of 9 feet 8 inches with a minimum bearing length of 3 inches at each end on 12 centers.
Most new construction uses 2 by 8 lumber for joists although 2 by 6.
Span calculator for wood joists and rafters also available for the android os.
If you want to put down flooring in your attic and want more insulation underneath that floor then you need to increase your joist size.
Measure the width and length of the existing joist.
The rule of thumb is 6 foot span with a 2 6 on 16 centers.
Joist span and spacing is set by your local building code.
Floor joist table joist size joist spacing maximum span 2 x 6.
Use your common sense when deciding how many fasteners are needed.
Splitting the wood does no good.
Hem fir 2 joists with a live dead load of 40 10 psf.
While most residential construction uses 2x8 joists with 16 inch spacing there are many other factors you need to consider when determining the proper joist span length.
Pictured at left is a diagram of some recommend prescriptive repair techniques for floor joists.