I have been model railroading most of my life and I have always used “built-up” structures. I have built plenty of plastic kit models in my life, as well as a wooden kit RC airplane with great success.
Now, I am interested in scratchbuilding a structure for my layout. I have never done this before.
There are couple of ways to get into scratch building. I would suggest getting one of the older “Craftsman Kits” made by Campbell or Northeastern/Ambroid and see how they do it. The only difference between these kits and you starting from scratch are many pieces are pre cut to size.
Another way is to analyze how a real structure is made an duplicate the pieces in 1/48 or whatever scale you model in. Most components like 2 x 4s or I beam shapes can be had in either wood or styrene. Many of the internal structural details could be eliminated in the model like framing for house.
Get acquainted with sources for parts like Grandt Line.
Most of the Scale Modeling magazines like Model RR, Finescale Modeler, Narrow Gauge Gazette have articles which show the step by step process of building a model.
Craig…If you live near a major metropolitan library, you might find many books and tapes on this subject. Our Franklin County, Ohio system has several different how to books on model railroading.