Is there a reliable source of unbiased information on masonry restoration and preservation?
Yes. The Historic Preservation Service division of the National Park Service (NPS) has established the official standards for the preservation of historic structures; these standards are The Secretary of the Interior’s Standards for the Treatment of Historic Buildings. The NPS also offers extensive web resources to help you interpret and apply these standards, and their online resource center includes their Preservation Briefs, which are the professional standard for preservation and restoration in the United States.