I have two separate exterior chimneys for my furnace and fireplace. The oustide concrete for the furnace chimney has cracked and some pieces have already fallen off. We recently installed a new stainless steel liner which was probably one of the causes of the cracking. Another reason is that the previous owner decided to go the cheap route and not wire the chimney before applying the stucco. Since a small part of the chimney stucco has already fallen off and there are line cracks on other sections of the stucco, is it possible to repair this without knocking off all the stucco and starting from scratch? The fireplace chimney has only a few small cracks barely noticeable but it seems that water already penetrated through the stucco and you hear a hollow sound when knocking on it, will waterproofing the stucco fix the problem? I want to try to fix this before it starts falling off like the furnace chimney? Is there a stucco that you can apply to a chimney that does not need wiring?