Sure, building deck stairs can be tricky. But in this story, we'll make it easy by showing you how to estimate step dimensions, layout and cut stair stringers, and assemble the stair parts. And you won't have to do any hard math to figure it all out (but your calculations will have to be accurate!). These DIY steps will work for replacing an old set of stairs and for building stairs on a brand new deck. So grab your tools and let's start building!