Question: how to convert plf to psf?
Answer: The load on each sq ft is 100 PSF. Therefore 2 ft + 2 ft = a tributary width of 4 ft x 100 PSF = 400 PLF along the beam. Note: Rafters and floor joists have a tributary load equal to their spacing, i.e., 12" on center, 16" on center, etc. Their PLF = PSF x spacing in feet.