I build a mantel awhile back and attached a 2x2 to the mortar via tapcon screws. The mantel fit over this like tendon and then I nailed through the bottom of the mantel into this tendon.
Worked like a champ. The corbals (sp?) are pretty much just show.
Here are 2 pictures. Unfortanely neither are that great. The first shows the tendon. The board under it is just for spacing. It goes into a hole in the back of the mantel (picture 2).
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