Mounting a fireplace mantel

[JMER817]

All great ideas! I think what I will do is close to my original idea, but will use the "French cleat" idea. I looked at them at Lowes today and the 18" length is rated to hold 200lbs. I will put 3 of these along the back and probably still put a small angle iron pc below. The grout and stone will cover the angle iron. There will be about I'm guessing a 1/4" gap from the mantel to the back wall from using the metal cleat idea. I will just caulk this which will be along the side and top of the mantel.

 

[RedNeckGeek]

A while back I mounted a 6' piece of 4x8 rough sawn cedar using three 1/2" lag bolts. First I found the studs in the wall, then marked the stud locations on a 6' 2x4 to use as a pattern. Drilled 1/4" holes in the 2x4 using a drill press so they were straight and square. Then I put the 2x4 up on the wall and used the holes as a guide when drilling the wall. Put the 2x4 on the back of the cedar mantle and drilled 1/4" holes, then enlarged them to 1/2". I made sure that the holes into the cedar were drilled from the opposite side of the pattern board than was used on the wall. I enlarged the holes in the wall to accept the 1/2" lag bolts, installed the bolts leaving about 6" sticking out (they were BIG lag bolts), then cut off the heads. Slipped the mantle onto the lags to check fit, then backed it off a couple inches and slathered the wall and bolts with construction adhesive before pushing it back in place. The wall turned out not to be very straight, so I had to caulk between the cedar and the wall to fill the gap, but the mantle was high enough to not show. A year later I tore it all out to install a wood stove, and needed a 4' crow bar to get the mantle board off, so I'd say it was plenty sturdy