Don’t let that scaffolding scare you off–we’re just repointing

DSCN4643_4438_edited-2From time to time, old buildings need some attention to their exteriors to shed the effects of the weather. Old brick and masonry structures need to constantly shed that old enemy, water penetration. In the case of our century-plus old building, the mortar joints between the bricks had worn away and needed to be cleaned and re-filled with fresh mortar. Called “re-pointing” or “tuck pointing”, this is a tedious job for skilled brick masons. The mortar used years ago was largely a blend of lime and sand, and is more “soft” than that used in more modern structures. This soft mortar was the sacrificial element, in that the mortar would have some give to it, and not be harder than the surrounding bricks. It is comparatively easier to replace the mortar in the seams than whole numbers of bricks in a given exterior wall. The new mortar used needs be compatible with the old bricks, and getting the blend just right is where the expertise of the brick mason comes in. In the hands of a mason with lesser skills, the use of modern mortar blends result in harder mortar seams that result in broken bricks in the wall. With moisture, freezing and thawing the bricks can’t “move”, as with the older types of soft mortar, and so the brick edges or facings will spall or chip away. When that happens, the building can no longer effectively shed water penetration. Today’s structures will use a brick that is fired to a much harder consistency, so the modern mortars will be more compatible in those buildings. Knowing which brick requires which type of mortar is key to a structure that will last centuries, and those that develop structural leaks and fissures, and soon begin to fail piecemeal.
Of course—sometimes brick walls will fail in other ways. Our building had settled over the years, and some bricks had broken in half from the shear force of parts of the wall shifting at different rates. Add to that the stresses suffered in all masonry structures around DC from our earthquake of 2 years ago, and it was time we had this wall tended to by a qualified masonry team. They will be done soon, and our building will be water-tight and solid, and ready to fend off the forces of nature for another century.