WHAT ARE THOSE POWDERY WHITE AREAS ON MY BRICK WALLS?
Efflorescence is one sign that is often dismissed as just being an eyesore and is given surface treatment only. This is the presence of the white powder that forms on the face or surface of concrete, plasterwork and brickwork.
It is a cause for concern!
Efflorescence is a build-up of minerals and salts on the surface of the concrete, brick and plasterwork due to repeated bouts of excess water in the material. The minerals and salts that naturally occur in the material are dissolved when the brickwork, plasterwork or concrete is waterlogged with water.
Concrete, pavers, brickwork and plasterwork are porous and can absorb or wick water and draw salts to it like a tree transports water from its roots to its leaves. This is capillary action. When efflorescence happens, it can indicate a moisture issue that could potentially damage the structure.
When water reaches a building material’s surface, evaporation will occur. Water absorption and wicking will continue after the water evaporates and the salt is left behind. This eventually creates a high salt concentration, leading to osmosis.
What is Osmosis
Simply put, osmosis in building materials is the movement of water from a region of low salt concentration to a region of high salt concentration in the material.
During osmosis, when water moves toward salts and minerals to reduce its concentration, it can cause large hydrostatic pressures within the porous building material. As a result, these pressures can damage or destroy the material.
Osmosis can cause pressure that ranges up to 200 bar, exceeding the structural strength of concrete. Therefore, osmosis may result in porous building material cracking, flaking or falling apart.
While the efflorescence is only a cosmetic problem in itself, its appearance on the wall indicates an ongoing water intrusion problem.
That means if you notice efflorescence on any concrete, plasterwork, brickwork and other structures, it’s important to take action by finding and eliminating the source of the moisture intrusion.
Most Common Causes of Efflorescence
- Garden irrigation systems:
One common cause of minor efflorescence is a sprinkler head that sprays on the walls of the building.
Repeatedly washed and wetted concrete can form efflorescence, such as a garage floor, stoop or paving.
- Leaks in walls:
A leaking water pipe or waste pipe in the wall of the building may cause efflorescence both internally and externally.
Water may accumulate within a wall as a result of condensation. Things that take place inside such as cooking, bathing, washing and other actions employing water internally causes condensation. During cold weather, building interiors heated to normal comfort settings may contain enough moisture to cause condensation on cooler walls or on the underside of ceiling and roofing materials.
- Contact with the ground:
When brickwork, plasterwork and concrete are in contact with the earth, groundwater may be absorbed by the material. Moisture may rise through capillary action several feet above the ground. This may occur in the building’s plinth brickwork and columns if there is water ponding against the plinth. Efflorescence also often occurs on the bottom of retaining walls.
Lack of roof drainages such as gutters and downpipes will allow rainwater pouring off the roof to splash up against the walls. This can cause moisture intrusion into the walls and efflorescence on the walls. The bubbling of the painted and plastered wall finishes will result.
- New buildings:
A new building will sometimes have a minor efflorescence bloom. The moisture still in the material from the building process is evaporated away during the first months following construction.
- Freestanding structures:
Chimneys, freestanding walls and parapet walls on balconies and roofs are the most susceptible. Often they have not been properly waterproofed or not waterproofed at all. They will most likely show signs of efflorescence in the top section of the wall.
- Water Ponding:
Water ponding on brick and concrete paving will cause efflorescence.
- Defective installations:
Roof leaks and leaks around windows and doors may cause efflorescence on the structure of the building.
Some of the best ways to remove efflorescence include:
- Pressurized Water:
Applying a strong jet of water may dissolve efflorescence quickly. If you use water, dry off the water from the building material after application. If you fail to remove the water, salts may remain that can cause efflorescence to reappear.
- Diluted Vinegar:
You can use diluted white vinegar on efflorescence. It’s less harmful than industrial chemicals. You most likely already have vinegar in your kitchen.
With a strong brush, you can remove efflorescence with ease.
Removing efflorescence can be quick and simple. In fact, efflorescing salts are water-soluble, which means efflorescence may disappear on its own due to normal weathering.
What can I do about efflorescence?
The fact that water has penetrated the structure is the root issue. Furthermore, the moisture intrusion will likely be the cause of the eventual repair or replacement work that will be required.
Efflorescence is associated with potentially severe underlying complications. Therefore, it is highly advisable to seek expert advice to determine the source of the moisture intrusion causing the efflorescence.
If you have an efflorescence problem or suspect there may be a leak somewhere in your home, it’s wise to call me before you call a repair company. Repair companies have a vested interest in getting work. As a result, you have to careful in accepting what they say requires repair or replacement.
I provide an unbiased opinion. I have no gain out of the evaluation of things that need repair (e.g., your roof or foundation).
Inspected Once, Inspected Right!®