RAM SS: Modelling Wood Diaphragms

Hello, 

I am trying to model wood roofs for some of my models (wood joists with plywood sheathing, wood trusses). I am considering them semi-rigid, but I do not know what properties to use (Modulus of elasticity, Poisson's ratio, etc.).

Are there any recommended values to use for modelling these types of roofs?

Thank you.