My apologizes, John! When I referred you to WCI I meant the book area. Fox Chapel has two excellent books on mantel construction.
The first one is on page 2 and the second is on page 3 or 4.
http://www.foxchapelpublishing.com/s...p=1&FullCat=17
Fireplace and Mantel

s, 2nd edition: Build, Design and Install Your Dream Fireplace Mantel
Author: John Lewman
Product Code: 2291
ISBN: 1-56523-229-1
Building Fireplace Mantels: Distinctive Projects for Any Style Home
Author: Mario Rodriguez
Product Code: 3855
ISBN: 1-56158-385-5
Susan