Why Older Brick Buildings Start Failing All at Once

One day, your beautiful brick building is standing proud; the next, you’re noticing cracks, loose bricks, even pieces of masonry on the sidewalk. In Greater Boston, where many brick structures have stood for a century or more, it can seem like they start failing all at once. As someone who’s been restoring historic masonry for decades, I can tell you: those “sudden” failures are usually a long time coming (and often preventable).

TL;DR: Old brick buildings often reach a tipping point after years of wear and tear. Weather, moisture, and aging materials quietly weaken the structure until one day multiple problems show up at the same time. It’s not truly “all at once” – the damage builds up slowly – but once it surfaces, it can look dramatic.

Why Do Older Brick Buildings Start Failing All at Once?

In my experience, brick buildings rarely truly fail overnight. Instead, small problems accumulate. Think of an old brick wall like a Jenga tower… you can remove a few pieces (a cracked mortar joint here, a bit of moisture there) and nothing happens immediately. But eventually one more piece goes, and the whole thing starts wobbling. Years of gradual damage reach a tipping point.

Moisture and New England Weather (Freeze-Thaw Cycle)

Boston’s weather is notoriously tough on masonry. Moisture is the number one enemy of brick. Rain soaks into bricks and mortar; when winter hits, that water freezes and expands inside the masonry. Then it thaws, then freezes again – each cycle pries the bricks and mortar apart a tiny bit. Over decades of freeze-thaw punishment, bricks can start spalling and mortar crumbles. Often, all it takes is one especially harsh winter to push an old, weakened wall over the edge. Suddenly you’ll see lots of brick faces popping off and chunks of mortar falling out in one season.

(A note from us: older bricks often aren’t as hard as modern ones. Many 19th-century bricks were fired at lower temperatures, making them more porous. Once their outer crust is compromised, they suck up even more water.)

Mortar Deterioration Over Decades

Mortar is the glue holding your bricks together, and it doesn’t last forever. In historic brick buildings (100+ years old), the original mortar is often a lime-based mix that gradually erodes or weakens. After many decades, it can turn soft or powdery. If a wall hasn’t been repointed (old mortar removed and new mortar installed) in, say, 50+ years, there’s a good chance the mortar is barely doing its job. It might look okay from a distance, but up close you’ll find it crumbling out of the joints. At a certain point, the bricks aren’t bonded firmly and may start shifting or falling with little warning.

Neglect is a big factor here. Little cracks or gaps in mortar let water in, which accelerates the decay over time.

Bad Repairs (The Hard Mortar Problem)

We get it done right the first time!

Sometimes, the culprit for a sudden failure is actually a past repair mistake. I’ve seen this a lot in older Boston buildings that were “patched up” mid-20th century. Back then, contractors often used modern Portland cement mortar to repoint old brick walls.

Unfortunately, that mortar is too hard for many historic bricks. Older bricks are softer and need to “breathe” and move a bit with the seasons. A hard, dense cement mortar doesn’t let them do that. The result? The bricks themselves crack and crumble under stress, often within a decade or two of the improper repair.

Structural Shifts and “Domino” Effects

Another reason it can appear to fail all at once is that one structural problem triggers others. Foundation settling is a prime example: if an old foundation sinks or shifts even a little, you might get a big crack in the brick wall. That crack lets water in (there’s moisture again!), which weakens the surrounding area faster. Soon, multiple cracks spiderweb out. Similarly, if a bulging brick wall (often caused by long-term moisture and pressure) finally gives way, it can make adjacent sections unstable, leading to a chain reaction of damage.

And let’s not forget external factors: For instance, say an adjacent building gets demolished or there’s heavy construction next door, the vibrations can jar an old brick wall that’s already on the brink, causing instant new cracks or loosening bricks. Again, it feels sudden, but only because the wall was already fragile.

How Can You Prevent “Sudden” Brick Failures?

Owning a historic brick building in Boston is a bit like owning a classic car – maintenance is everything! You can’t just set it and forget it, or you’ll be hit with big problems down the line. The good news is, with some TLC and vigilance, you can prevent those nasty surprises. Here’s what I recommend:

• Keep Water Out: Make sure any gutters and downspouts are clean and working, so rainwater isn’t pouring down your walls. Check that the roof is sound and flashing (the metal sealing at roof-wall junctions, chimneys, etc.) is intact. Seal up any obvious gaps around windows or openings. Basically, eliminate leaks and poor drainage, because water seeping into brickwork is the start of most problems.

• Repoint Mortar When Needed: As a rule of thumb, if your mortar is crumbly or receding more than about 1/4 inch from the face of the brick, it’s time to repoint. Proper repointing will restore the wall’s strength and keep water out of the joints. It’s one of the best preventative measures to avoid sudden failures.

• Address Small Problems Promptly: Don’t shrug off that one weird crack or a couple of spalling bricks. Fixing one loose brick now is a lot easier (and cheaper) than rebuilding a whole corner later. Replace cracked bricks, patch small foundation cracks, and tuckpoint minor mortar gaps before they widen. Each little repair you do prevents water and weather from exploiting the weakness further.

• Monitor and Inspect: Every year or two, do a walk-around inspection of your building (or have a professional like JMS Masonry do an annual inspection for you). Think of it as a check-up. You’re looking for new cracks, areas where mortar has washed out, signs of settling, etc. In older buildings, I’d also peek in the attic or basement for any telltale leaks or cracks that might telegraph issues in the masonry. Regular inspections mean you catch the slow-burn problems before they reach that all-at-once tipping point.

By staying on top of these things, you’ll greatly reduce the chance that your lovely old brick home or building will ever visibly fail “all at once.” Instead, you’ll tackle the wear-and-tear issues continuously, keeping the structure stable and safe. 

About JMS Masonry

JMS Masonry & Restoration is a masonry company based in Massachusetts, proudly serving the Greater Boston area (and beyond) for over two decades. Founded by John Screen, a master mason trained in London, we specialize in preserving and restoring historic brick and stone structures. From historic brick repair in Boston to foundation repair, our team brings old-world craftsmanship and modern expertise together. We’ve built a reputation as one of Boston’s leading masonry restoration companies, with projects ranging from 19th-century brownstones to landmark commercial buildings. (If you live within 20 miles of Boston, you’ve likely walked by some of our work without realizing it!)

Feel free to contact us for an inspection or quote – whether it’s a growing crack or a full façade restoration, our experienced masons are ready to see how we can help.