Glossary of Terms – Efflorescence

Glossary of Terms – Efflorescence

In Chicago, you’ll sometimes see a white, powdery crust on brick walls. This is called efflorescence, and it’s a common issue in our city. To understand this phenomenon and how it’s fixed, it helps to know the terminology. Here, we’ve compiled a glossary of efflorescence terms to help you dive into the subject. If you have any questions or want professional input regarding efflorescence on your own building, don’t hesitate to contact our masonry specialists today.

Efflorescence

What is efflorescence? In the simplest terms, it’s a deposit of salts that shows up on the surface of buildings. When water inside your walls moves to the surface and then evaporates, it leaves behind salts that look like a chalky residue.

In Chicago, we have rain, freeze-thaw cycles, and humidity, and all of these elements make efflorescence especially common. Seeing efflorescence doesn’t mean your building is ruined, but it does indicate there’s moisture moving through the masonry.

Brick Efflorescence

Brick efflorescence is one of the most common forms of efflorescence and looks like a white haze or streaks on the face of the brick. This happens because bricks are porous and act like sponges, pulling in water. When the water eventually escapes again, it carries salt from within the brick and leaves it on the building’s surface. 

Efflorescence in Bricks vs. Mortar

Sometimes efflorescence comes from the bricks themselves, and sometimes it comes from the mortar joints between them. Mortar often contains cement and lime, which can produce different kinds of salt deposits. Knowing whether your efflorescence is brick-based or mortar-based can help you figure out the best cleaning method.

Efflorescence Masonry

Bricks, mortar, stone, and concrete are all part of efflorescence masonry. In essence, efflorescence is the natural byproduct of moisture migration in any kind of masonry. If you’ve got masonry in Chicago, odds are you’ll see efflorescence at some point.

Primary Efflorescence

This is the type of efflorescence that shows up right after the masonry is built. The materials themselves had salts inside, and as soon as water passes through, it carries those salts out. If you’ve ever noticed brand-new brick construction in Chicago looking dusty or white, that’s most likely primary efflorescence.

Secondary Efflorescence

Secondary efflorescence happens later, long after construction. This usually comes from outside sources like de-icing salts from Chicago’s winter roads. When salty water splashes onto your walls and soaks in, the salts will eventually work their way back out as efflorescence.

Hygroscopic Salts

Hygroscopic salts are salts that absorb moisture from the air. This means that even if it hasn’t rained, your bricks might still look damp or salty on a humid Chicago summer day.

Salt Crystallization

When water evaporates, it leaves behind crystals of salt. Over time, this salt crystallization can form the powdery buildup you see on brick buildings. Unfortunately, in severe cases, crystallization inside the brick can cause cracking or spalling, which is when the surface of the brick flakes off. This is a more serious issue and may require calling in a professional for repair. 

Efflorescence Remover

An efflorescence remover is a cleaning solution that can break down and wash away salt deposits. These removers are usually acidic, which dissolves the salts. In Chicago, you’ll often find masonry contractors using specialized products to safely clean efflorescence without damaging the brick. 

Pressure Washing

Pressure washing uses water at high pressure to clean masonry. While it can be effective, it’s important to be careful with Chicago’s older brick buildings, since too much pressure can erode the brick and actually make efflorescence worse by driving water deeper into the wall.

Vapor Permeability

If you want to manage efflorescence, it’s important to understand vapor permeability. Bricks need to breathe, which means moisture vapor should be able to escape. If you seal bricks with a non-breathable coating, you’ll trap moisture inside the material and potentially cause yet more efflorescence. If you’re using a masonry sealer in Chicago, it should always be vapor-permeable.

Capillary Action

Capillary action refers to the way in which water moves through small pores in bricks. Capillary action is the reason efflorescence spreads across large areas of brick walls.

Freeze-Thaw Cycle

Chicago is known for its freeze-thaw cycle, which is where water in your masonry expands when it freezes and contracts when it thaws. This constant stress can create more ways for water to move, making efflorescence more common and sometimes more severe.

Spalling

When salt crystallization or freeze-thaw damage goes untreated, the surface of your brick can flake and peel off. This is called spalling. While efflorescence itself is usually just cosmetic, spalling is a sign that the bricks are being damaged and need professional attention.

Subflorescence

Subflorescence happens when salts crystallize inside the brick, not on the surface. This can be a problem because it builds internal pressure that will eventually crack the masonry.

Hydrostatic Pressure

If groundwater is pressing against the outside of a basement wall, that pressure pushes water into the masonry. This is called hydrostatic pressure and is one of the main causes of efflorescence in Chicago basements.

Waterproofing vs. Damp Proofing

You’ll sometimes hear these terms when contractors talk about preventing efflorescence. Waterproofing is a full barrier against water that won’t let liquid in at all. Damp proofing, on the other hand, slows water absorption. For masonry in Chicago, waterproofing plus vapor permeability is usually the best combination.

Efflorescence vs. Mold

Efflorescence is salty, powdery, and can be brushed off easily. Mold is organic, fuzzy, and usually green, black, or brown. If your wall is white and chalky and you live in Chicago, it’s almost always efflorescence, not mold.

Tuckpointing

If your mortar has cracked and lets water in, you’ll see more efflorescence. Tuckpointing can be used to seal those gaps and help keep your walls looking clean.

Learn More About Efflorescence With Jagra Masonry 

Understanding these efflorescence terms can help you make better choices if you’re dealing with masonry issues. If you have any questions or want the opinion of an expert, Jagra Masonry can help.