I have a chimney that has 4 large stone pieces at the top that make up the cap. The problem is that the mortar has deteriorated and 1 of the pieces has actually fallen off. Also on top of this there is cement that is sloped from the flue to the stone pieces. This has completely crumbled and is falling off of the chimney as well. What type of mortar or cement should I use to fix this. Also if I were to have a Mason do the work, any idea of how much it would cost? Lastly, I have seen 1 piece pre-cast caps for chimneys, but, they are only about 2 inches high and are not decorative. My cap is about 4 inches high and has some decoration to it. Does anyone know if decorative 1 piece caps are available?