How to Tell if Your Building Needs Repointing Work
With ice, rain, snow, and low temperatures, winter is clearly the season that hits a brick façade the hardest. Problems already present in the façade are sure to grow as moisture in cracks and cavities expands in freezing temperatures. To the site manager, this means that summer is the best time to gather contractor bids and to catch up on needed masonry repairs before late fall, when demand for repointing work is highest, and before the onset of winter.
Repointing, the chiseling out of old, worn mortar between bricks and having it replaced with fresh mortar, is undoubtedly one of the most common maintenance procedures a brick building will undergo. Unfortunately, it's also one of the most expensive. The following is a complete guide to what repointing is exactly, why it's necessary, and how to tell whether your building needs it. In an upcoming issue, we will also tell you how to get the most for your money once a repointing project is underway.
What Is Pointing?
In a masonry building such as a brick, stone, or concrete building, pointing is the mortar that holds the pieces together. These areas between the bricks and stones are called “mortar joints,” and they glue all the different parts of the façade into a whole.
Besides binding the bricks, pointing also forms a watertight seal between these pieces of the building. As soon as this seal is violated, you can expect the mortar or pointing to deteriorate rapidly—and your masonry to follow soon after. Initially, water causes damage by making the lime, the mortar's binding agent, disintegrate. As the defective mortar joints steadily loosen, they become more vulnerable to snow, wind, and acid rain, which threaten the stability of the building.
Risks When Pointing Breaks Down
The most dangerous result of letting your building's pointing disintegrate is the destructive effect it will have on bricks. If the mortar between bricks falls apart, water can seep behind the face of the wall, soaking the bricks and destroying the walls of the building.
In winter, the effect is even worse, because moisture will freeze up and expand, pushing the bricks outward. This is how “bulges” appear on building walls. Even more ominous for the owner is when the invading water soaks into the meal girders and supports of the building. The resulting rust expands the metal, wrecking havoc with a building's superstructure.
So when you have a repointing job done, you're taking a preventive maintenance measure to preserve the outside walls of your building. And you're preventing water from leaking in and destroying interior supports.
Fundamentals of Repointing
Here's how the repointing process works: A contractor cuts out the old, decaying mortar using a mechanical grinder and hand-cutting tools. Building inspector Richard Madigan recommends that the cut into the old mortar be a solid inch deep, enough to make sure all the bad mortar is extracted, but not enough to threaten the stability of the bricks while the work is going on. Then fresh mortar is applied to these new gaps, to roughly the level of the face of the bricks.
Finally, these damp joints should be “tooled” or pressed compact. This last step, frequently ignored by contractors who want to cut costs with less labor, will assure a good, new watertight seal.
Telltale Signs of Need to Repoint
Finding out you need to repoint should never be as dramatic as having a brick fall out of the façade with its possible legal consequences or seeing a wall begin to bulge. Here are some tests a manager or owner can perform—without calling in an engineer or architect—to see whether repointing is necessary.
Check roof. Go to your roof and look for loose masonry and coping, the top layer of masonry on a parapet wall. Loose coping stones mean, almost for sure, that there is water seeping into the structure, says Madigan. Check for cracks and stains on the roof of the building, where it meets the wall. This is a tipoff that water may have seeped into the façade because of holes, cracks, or leaks in the bricks, masonry, or coping stones.
Check mortar of parapet. While on the roof, check the mortar of the parapet, the portion of the wall that extends above the level of the roof. To do a mortar check, try to poke out the mortar in the joints between the masonry using a pencil or even just your finger. If the mortar is solid and cannot be penetrated or scraped away, then you're probably fine. But if you can poke into or scrape out the mortar between the masonry, or if there are spaces between stones where the mortar has completely flaked away, chances are your building needs repointing.
Check mortar in upper stories. As best you can, using windows, balconies, or fire escapes, check some of the mortar in the upper stories of your buildings. These are the sections where you can expect problems to arise first, according to information gathered from Culbertson Restoration, a Philadelphia-based contractor.
The upper floors are more likely to need repointing because they get more exposure to the elements than the lower and generally are not as well maintained. If you're reluctant to probe a patch of masonry because it's hard to reach, at least check visually for white stains called efflorescence, which bleeding, water-damaged mortar will form on the bricks as another sign of trouble.
Richard Madigan: The Building Inspection Group/Christopher Compton Architects, 4000 W. Riverside Dr., Burbank, CA 91505; www.christophercompton.com.