I remember thinking some years ago that Bob Walker’s Scratchbuilder’s Corner column in Railroad Model Craftsman embodied a wealth of knowledge that should be turned into a book. This was apparently not a special insight since not long after, along came Scratchbuild for Model Railroaders. If you ever intend to build a structure be it kit or from scratch, you would do well to own a copy of this book as a reference. Note the dogeared corners on mine.
In the same self-deprecating conversational style he uses in his columns, Bob covers everything related to scratchbuilding structures from basic tools and materials all the way up to moulding and casting. Things are spelled out in straightforward fashion and include warnings on common mistakes.
We are fortunate that White River Productions has picked up and continued the Carsten books including this one so you can buy it new online right now. There is a lot of information packed into this volume and at $19.95 USD it is probably just about the best value for money available in the hobby today.