Troubleshooting - Chimney and Crowns
Spalling Chimney (brick face damage) or missing mortar:
There should always be a gap between the flue tile and the chimney crown. Often, when crowns are mortared right next to a tile, the crown may lift when the tile is heated and expands. This lets moisture in and can result in freeze/thaw damage. The best way to remedy this situation is to replace the crown and rebuild the top rows of spalled brick. An exterior mortar such as Rutland® Exterior Chimney Masonry Patch or type M Mortar mixed with PWR® must be used.
White Stains on Chimney Exterior:
Efflorescence is white mineral salts that are deposited on the exterior of the chimney when moisture wicks through the mortar joints. This moisture can be in the form of a missing chimney cap, missing or damaged mortar joints, porous brick or a gas appliance being vented directly into the chimney. ChimneySaver® Brick & Mortar Cleaner may help to remove some of the stain; otherwise a mixture of muriatic acid and water usually cleans it up. Muriatic acid is usually a last result because it can etch the brick and special precautions must be used when applying it.
Often, the efflorescence can be brushed off or cleaned with water and a stiff brush. If the brick or mortar joints are porous, treating the chimney with ChimneySaver® Water Repellent and repairing the joints with Crack Magik®, often preserves the chimney and eliminates complete replacement.