Just for my info, what is the typical riser material and thickness for staircases?

Ken

Riser material can just about be anything. For painted risers, it can be any paint grade wood such as pine, fir, alder, poplar, maple, MDF, plywood, etc. For stained risers, it is usually the same species of wood the treads are made of. Oak is the norm but pine was used centuries ago and fir is also used occasionally. Some will veneer old risers with a new veneer. The thickness can be as little as a thin veneer and as thick as 3/4". It depends on what is needed. I've even seen ceramic tile used for risers on spanish style architecture.