The white powder is efflorescence: salts dissolved in water that moved through the brick or mortar and stayed behind when the water evaporated at the surface. It is a moisture symptom, not structural failure. Dry brushing usually removes it, but it returns until the source of the water is found and fixed.
Efflorescence on brick is one of the clearest signs a wall gives about how water moves through it. True Course Masonry Newark traces and repairs the masonry water paths behind it across Newark and Essex County, with the work carried out by licensed and insured contractors. This guide explains where the salt comes from, what different patterns suggest, how to clean it without harm, and when it is a sign of something more. Related wall problems are covered on the masonry repair page.
Where the salt comes from
The Brick Industry Association’s Technical Note 23A lists the conditions that have to exist at the same time. Soluble salts must be present in or touching the brickwork. Water must stay in contact with them long enough to dissolve them. And the masonry must have a pore structure that lets the salt solution travel to a place where the water can evaporate, pushed by a temperature or humidity difference. Take away any one and the bloom stops.
People tend to blame the brick, because the white shows up on it. The BIA notes that the salts more often come from materials in contact with the brick: mortar, concrete, block backup, soil or other materials. Brick is simply where the water surfaces and evaporates, and white reads clearly against red.
Around Newark houses, the usual salt sources are:
- Mortar and backup masonry. Cement-based mortar and concrete carry soluble compounds that water can leach out.
- Soil and ground water. Brick in contact with soil, or wicking moisture up from grade, carries ground salts with it. On low ground in the east of the city, much of it former marshland, ground moisture is more likely to be part of the picture.
- Deicing salt. Salt spread on stoops, steps and sidewalks is splashed and melted into the lowest courses.
- Floodwater. Ironbound homes soaked in brackish Passaic River water during Superstorm Sandy in 2012 took salt deep into their masonry, and salt from an event like that can surface for years.
What the pattern tells you
On new brickwork, the BIA calls the deposit “new building bloom”: a fairly even haze across the wall as construction water dries out, which usually fades within months. Efflorescence that appears more than a year after construction, the BIA notes, usually traces to excess water getting in or poor drainage, and is often worst in winter or cold weather, when walls stay wet and dry slowly.
On an older wall, look at the shape:
| Where the white shows | Common water source to check |
|---|---|
| Below a gutter seam, downspout or scupper | Overflow or leaking drainage |
| Under a window sill | Sill with no slope or drip, or open sill joints |
| Beneath a coping, cap or chimney crown | Cracked or flat top letting water into the wall core |
| A band along the bottom courses | Splashback, snow piles, salt, wet soil |
| A horizontal line on the inside of a basement or old wall | Ground moisture wicking up |
| Around a chimney inside the attic | Crown, flashing or masonry leak above |
| Spread evenly across a newly built wall | New building bloom |
Chimneys deserve a note. White staining on a chimney, outside or in the attic, often points to water entering at the top or at the flashing; the chimney leak guide explains how to tell a masonry leak from a flashing leak, and the chimney repair page covers the masonry fixes.
Is efflorescence a structural problem?
No, not by itself. The salt on the surface does not mean the wall is failing. What it does prove is that water is moving through the masonry, and water is what drives most masonry damage. If the bloom is heavy and keeps returning, the same water may also be freezing in the brick or carrying salts that crystallize just under the face, which can spall brick. That is the point at which efflorescence stops being a cosmetic nuisance; the spalling brick guide covers what happens next.
When it needs more than a brush
Get the water path looked at if:
- the white comes back in the same spot season after season
- brick faces near the deposits are flaking, powdering or popping off
- the deposits sit below a coping, sill, chimney or roof edge
- interior plaster or paint near the deposits is bubbling or damp
- the wall was recently sealed or painted and the bloom appeared behind or around the coating
Usually fine to watch when:
- the wall is new and the haze is even
- light deposits appeared after an unusually wet spell and fade as the weather dries
- the brick underneath is hard and sound
How to clean it gently
The BIA notes that most efflorescing salts dissolve in water and many disappear with normal weathering. When they do not, start mild:
- Brush it dry. A stiff natural or nylon brush on a dry day removes most deposits. Collect the powder rather than rinsing it into the wall.
- Avoid washing in cold, wet weather. The BIA advises against washing efflorescence off except in warm, dry weather, because the extra water can carry more salt to the surface.
- Test any cleaner first. If a specialty masonry cleaner is needed for heavy deposits, try it on a small, inconspicuous area and let it dry before judging.
- Skip the pressure washer and harsh acids. High pressure drives water deep into the wall, and strong acids can etch brick, attack lime mortar and leave their own stains.
The cleaning brick without damage guide covers methods for broader cleaning.
Finding and fixing the water
Cleaning removes the evidence; it does not change the cause. The repair that ends efflorescence is the one that keeps extra water out of the wall or lets it drain: clearing and redirecting gutters and downspouts, regrading soil away from the brick, rebuilding a cracked coping or crown, adding a drip or slope to a sill, opening blocked weeps on a veneer wall, and repointing open joints that let rain in. The when to repoint brick guide explains how to judge the joints, and the brick repair page covers damaged units.
What not to do: do not seal the wall to hide the bloom, for the reasons the should you seal brick guide gives, and do not plug weep holes to stop staining below them.
A next step
Over the next few weeks, brush the deposits off one area and photograph it each week, especially after rain. If the white returns in the same shape, the water source is above or behind it. Send those photos, with one showing the gutter, sill or coping above, through the contact page, or work through the questions in the masonry damage assessment.