Restoration and remodeling projects always wind up with a short list of details that require attention — a punch list. Similarly, writing this column produces a punch list of questions and comments from readers that need to be addressed. James Koger writes from Los Angeles: "Recently I inspected an old, turnof- the-century, Philadelphia brick row house, and there is one thing that bothers me. I noticed the mortar joints were very thin, averaging about 1/8 inch. Is it possible joints of this thickness were constructed on purpose? Or, could poor mortar dissipate (grain by grain) over time?" Thin mortar joints, sometimes called "butter joints," were often used from the late 18th century throughout the 19th century. Early masons knew the purpose of