Memorial Building Facade Repairs Continue

IRONWOOD, MI - Monday, July 28, 2008 - Repointing mortar joints and replacing flashing are both part of the repairs being done each day as part of the Memorial Building Facade Improvement.

Renewing mortar joints in masonry construction is commonly known as "repointing." Weathering and decay, over time, causes openings in the joints between masonry blocks which allow water to penetrate. Significant damage through freeze/thaw cycles and from salt dissolution and deposition can be caused once water has entered these openings. Many times people refer to repointing as  "pointing," or "pointing up," although these terms more properly refer to the finishing step in new construction.

In the Midwest and Northern United States, including the Upper Peninsula,  some confusion may result as the term "tuckpointing" is often used interchangeably with "pointing" and "repointing." Tuckpointing is a method of using two contrasting colors of mortar in brickwork, one color actually matches the bricks themselves, to give the false impression that very fine joints have been created.

Sound mortar normally does not need to be removed from a building during the repointing process, although such a practice is common. New mortar can be designed to match the color and texture of existing mortar to avoid visual aberrations. The repointing process begins by removing damaged pointing to a depth equal to or slightly more than the width of the joint, or to the point where sound mortar is reached. Depths greater than 2-1/2" should be filled in several passes, allowing the mortar to cure for at least 24 hours. The joint profile should be as rectangular as possible as the new pointing mortar should be allowed ample opportunity to bond with the masonry unit.

Removal of old mortar between joints should be done carefully to avoid damage to masonry units. On very old buildings with soft materials, such as under-fired brick, removal by hand is often the most effective to avoid damage. Hard Portland cement mortar is usually removed with a grinder or power circular masonry blade, taking care not to damage the masonry units. Vertical joints in most cases are always done by hand or with small power chisels.

Flashing is thin continuous pieces of sheet metal or other water-shedding material installed to prevent water from penetrating into a structure from an angle or joint. The principle that flashing is based upon is the fact that gravity automatically pulls water in a downward direction. Water would have to work itself upward, against the force of gravity or in the case of wind-driven rain in order to infiltrate the structure.

On June 23, 2008, the City Commission accepted a bid of $53,000 from Wayne Nasi Construction to do the work.