Winter maintenance · water and masonry
Why does brick start crumbling after winter?
Take a look at a brick that is starting to crack or lose its face. It is easy to blame the cold. But the more useful question is where the water is coming from—and what happens when that water freezes inside the material.
The short answer
The water expands. The brick has to deal with it.
When enough water gets into the pores or cracks of masonry and freezes, the resulting pressure can damage the material. Thawing lets more water enter the damaged areas. Another freeze can make the problem worse.
That is freeze-thaw damage. Preventing repeated saturation is usually more useful than waiting for a piece of brick to fall off and covering the spot.
Start with water management: look at roof runoff, downspouts, splashback, sprinklers, and damaged wall details. A surface repair is only part of the job if the wall keeps getting wet.
Most materials shrink as they cool. Water behaves differently.
In the video, I start with something that sounds backward: winter can create expansion problems around the house. That does not mean the brick, wood, and every other solid simply get bigger because the air gets colder.
Most materials generally contract as they cool. Water is unusual. When it freezes into ordinary ice, its molecules arrange into a more open structure. The same amount of water now needs more space. USGS explains the molecular arrangement and why ice is less dense than liquid water.
The NIH freeze-thaw bulletin describes roughly a 9% increase in volume as water freezes. That is a material property, not a prediction that your wall will expand by 9% or crack every time the temperature drops.
The important question is what surrounds the water. Ice forming in an open puddle has room to grow. Water freezing within a sufficiently saturated, rigid material can put pressure on the surrounding pores and cracks. If the resulting stress exceeds what that material can resist, damage can develop.
A small opening can become a repeat problem.
The video shows a crack in exterior brickwork and a separate view of badly deteriorated masonry. Those views illustrate what to notice; they are not a documented before-and-after of the same brick or proof that freezing caused every visible defect.
Brick looks solid, but it has pores. Water can enter those pores, as well as existing cracks and deteriorated mortar joints. It does not always need an obvious hole that you can point to from the sidewalk.
Now follow the sequence. The brick gets wet. The temperature drops enough for that water to freeze. The pressure can enlarge a crack or break down part of the material. When conditions warm, the ice thaws. That damaged area can take in more water before the next freeze.
Over repeated cycles, the surface may flake away. The term for pieces breaking away from a masonry surface is spalling. Damage can also begin inside the material before it is visible on the face.
Not all bricks respond the same way. Their pore structure, weathering resistance, condition, and moisture exposure matter. Properly selected and maintained exterior brick is designed to handle weather. The concern is not “all brick fails in winter.” It is repeated wetting and freezing in a vulnerable part of the assembly.
And it is not just a contest to see which day is coldest. Weather that repeatedly crosses between freezing and thawing can create more opportunities for this cycle than a period that stays frozen. How quickly damage develops still depends on the actual materials and exposure.
Before you replace the brick, ask why that spot stays wet.
If one part of the wall is deteriorating faster than the rest, I want to know what is different there. Is a gutter overflowing above it? Is a downspout splashing against the lower courses? Does a sprinkler wet the same area day after day?
Roof edges, window sills, flashing, and the tops of masonry walls all affect how water is shed. Standing water or soil held against the wall can also keep materials damp. The National Park Service's moisture-control guidance points to these water-management details before major alterations.
That is why this connects to the foundation drainage lesson. The downspout outlet and the ground slope are not separate from the masonry conversation. They help decide where water ends up after it leaves the roof.
A replacement brick may improve the surface, but it does not correct a gutter that keeps dumping water on it. Find the source, correct it, and then choose the right repair for the damaged material.
Different materials move differently. Do not seal every opening.
The animation also looks at a joint between materials. Metal, wood, and masonry do not all respond to temperature and moisture in exactly the same way. Wood's movement is strongly affected by changes in moisture, not just outdoor temperature.
A joint that has opened up can give water a path into the assembly. But not every opening is a defect, and not every opening should be filled. Some joints accommodate movement. Weep openings in a brick veneer wall let collected water drain out.
Do not caulk every gap in the brickwork or block the weeps. Have the wall details identified first. The goal is to maintain the intended water-shedding and drainage system—not make the outside look completely sealed while water is trapped behind it.
A moving step, slab, or exterior gap also needs context. Freezing conditions can be involved, but a gap alone does not establish frost heave, settlement, or structural failure. The movement pattern and the site conditions need evaluation.
A useful winter check starts from the ground.
Walk around the exterior when footing is safe. Look for fresh chips beneath masonry, brick faces peeling away, deteriorated mortar, persistent damp patches, and roof runoff landing against the wall. Photographs from the same safe spot can help show whether a concern is changing.
Arrange cleaning or repair of overflowing gutters and damaged downspouts. Keep sprinklers from repeatedly soaking the wall. Check whether water drains away after rain or snowmelt. Do not climb an icy roof or ladder, pull loose masonry toward you, or chip ice off a failing wall to investigate.
Why a coating is not the automatic answer
A can of masonry sealer can look like the easy fix. But it cannot restore a damaged brick, repair flashing, or replace drainage details. Some coatings can also interfere with drying.
The Brick Industry Association's maintenance guidance recommends correcting the moisture problem and evaluating repairs first. Water repellents may have a place in selected situations, but compatibility and the wall's ability to release moisture matter. Film-forming coatings are not the default answer for exterior brick.
For deteriorated mortar, a qualified mason may recommend repointing. For damaged brick, replacement may be necessary. Repair materials need to suit the existing masonry; a very hard mortar is not automatically the best repair for softer older brick. Do not pressure-wash or aggressively grind failing masonry as a way to diagnose it.
Loose masonry or visible wall movement needs prompt attention. Keep people away from anything that could fall. Bulging, displaced units, or cracks that are growing should be evaluated by a qualified masonry professional; structural concerns may require an engineer. A picture or this video cannot establish the wall's stability.
The next questions homeowners tend to ask
Does a crumbling brick prove freeze-thaw damage?
No. Freeze-thaw is one explanation to consider, especially where masonry repeatedly gets wet and freezes. Other material, salt, installation, and movement problems can overlap. The appearance should be evaluated alongside the water source, construction, and history.
Does Utah's dry climate prevent it?
No. A wall can still be soaked by snowmelt, a leaking gutter, or irrigation. What matters at that location is how wet the material gets and whether it freezes—not just the region's average humidity.
Should I fill every hairline mortar crack?
Not automatically. Wall type, crack location, water penetration, and movement all matter. Some drainage-type walls can manage limited water entry through their intended drainage system. A mason should help decide whether repair is needed and which joints must remain functional.
Can it damage concrete too?
Yes. Sufficient moisture and freezing can damage concrete as well as brick. Concrete mixture, air entrainment, condition, and exposure affect its resistance. Do not assume that every flaking concrete surface has the same cause as the brick in the video.
Winter is easier on a wall that can shed water and dry.
That is what I want you to take from this lesson. Do not wait until a brick face falls off to start asking where the water is going. Look at the runoff, the joints, and the details that are supposed to keep the assembly from staying saturated.
If you are buying a home or trying to understand exterior deterioration, an inspection can document visible conditions and help put the next questions in order. It is not a structural certification or a guarantee that concealed damage has been found.
Open the original Instagram Reel or return to every Learning Center post.
Keep following the water.
Foundation drainage and roof runoff explains what happens outside. Dryer vent leaks in the attic follows water vapor introduced inside the home. The foundation crack guide gives more context for cracks that need a closer look.
Further reading
The supplied video explains the concept through exterior footage and illustrations. These sources add the material-science and maintenance context:
USGS: Water Density
NIH: Freeze-Thaw in Concrete and Brick Assemblies
Brick Industry Association: Maintenance of Brick Masonry
National Park Service: Controlling Unwanted Moisture