Calculating the size of the floor joists you need when building a home or an addition is not a complex situation as we have provided a chart that will allow you to make your selection.
Note: Always check with your local building department to ensure that your choice of floor joist size and material meets their requirements.
Four charts are provided:
- 40 psf and 12″ spacing
- 40 psf and 16″ spacing
- 30 psf and 12″ spacing
- 30 psf and 16″ spacing
![floor joists - 30 psf - 12″ spacing - part 1](images/floor-joist-12-30-1.jpg)
![floor joists - 30 psf - 12″ spacing - part 2](images/floor-joist-12-30-2.jpg)
![floor joists - 30 psf - 12″ spacing - part 3](images/floor-joist-12-30-3.jpg)