How Do You Fix Crumbling Chimney Mortar?
Avoid extensive, costly damage to a masonry chimney. Maintain the mortar joints by tuck-pointing (repointing) them, and make sure the chimney crown remains sealed against water. Tuck-pointing masonry joints Work from the bottom up to remove loose mortar a few feet (a meter or so) at a time. Set up ladders or scaffolding if necessary. Use a mason’s hammer and chisel, a scraper and similar hand tools for difficult-to-reach areas. For extensive tuck-pointing, rent an electric grinder with a tuck-pointing attachment and blades. Mix water into a packaged mortar mix as directed on the label, using a cement-mixing container and hoe. Apply the mortar by first loading the bottom side of a square mason’s trowel (or a board) with mortar (see A). Then, holding the trowel against the chimney just below the joint you’re filling
