How to calculate stair headroom
I want to add head room calculations to my stair calculator http://www.blocklayer.com/stairs But I'm not real sure about the lower point to measure from. I was going to add inputs for the opening length and floor thickness, as in the drawing below, but should headroom be measured from the top line of the stringer (as diagram) or from the next highest tread? Am I on the right track here? I also thought if the headroom was below regulation, I'd mark it on the drawing. What is the minimum headroom (in Australia) All suggestions welcome (Don't forget, I'm a blocklayer)
Thanks for any input.
http://www.blocklayer.com/HeadRoom.gif