I like a very safe size rather than figuring everything too tight. Span Calculator for Wood Joists and Rafters available for the iPhone and iPad. (Maximum spans for Douglas fir-larch, hem-fir, southern pine and spruce-pine-firb and. You never know when the client will call and want to add an air conditioner on the roof, or they’re going to invite you to their 50th anniversary out on their deck. Simple clicks on the drop down boxes will allow variable inputs to calculate a.
