Well done

Extra thanks for adding in the different "age" of the materials. 

Weathering everything we often forget to think about our period modeled versus the age of the item.

Roofs are my favorite subject

Yes, this is the first part of a structure we see when viewing a layout. It may not be the focus, but a roof prepared in this fashion will attract the eye.

Great article! Can't wait to try it.

Excellent!

I'm going to use these techniques from now on! 

Great!

I thought those roofs were actual paper material.  I am very impressed how you modified styrene roofs to be so realistic.  Now I have some structures on my layout I need to rework!  Excellent job.

Thank you everyone!!

Thanks for the kind words everyone! I really am impressed what a bit of time, paint, and practice can create!

roof weathering

Economical, effective, excellence !  Greg's techniques are applicable for most modeling.  It's thoughtful in picture 8 to mention "flat blade to lift, stress, and cut the plastic", cautioning the inexperienced to keep fingers clear !