A chimney wash, or chimney top, capped with copper sheet metal flashing.

Originally covered with  traditional mortar , this chimney wash was re covered with copper flashing to stop persistant leaking.

The chimney wash is the top of the chimney above the brickline.  Normally there is a thick layer of the same mortar used to hold the bricks piled on the top of  the chimney to shed water. At the center of the chimney, around the clay flue liner, the wash is approximately two to three inches thick tapering to a half inch or so at the edge of the brick.

On many chimneys, especially larger ones, this mortar wash tends to crack and deteriorate over the years. Cracks open up in the mortar and allow water into the brick work and interior of the chimney. Freeze/thaw cycles exacerbate the problem and soon the chimney is falling apart.

The usual course of action is to either add more mortar, or worse, asphalt cement smeared  to the top of the chimney to stop the leaking. Either is a temporary fix.

This particular chimney is part of a Frank LLoyd Wright Usonian style house near Cleveland, Ohio. The current owner wanted to restore the house to it's original condition or better. For the chimney we opted for better. The original mortar wash, and all the additional layers of mortar and tar were removed. The brick work repaired ( special brick had to be made to fit the angles). And a new mortar wash installed. After the mortar cured new copper flashing was  fabricated to cover the mortar. The copper sheet metal was cut to follow the angles of the chimney, fastened with copper nails driven into lead plugs set in the mortar, and lock seamed and soldered for a permanent leak proof chimney covering. The chimney wash flashing has a drip edge around the perimeter of the chimney that helps to shed water away from the chimney bricks. The chimney flue cap was in good condition and re installed.