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Buffalo Foundation Repairs

Serving Buffalo and nearby areas

White Powder on Basement Walls in Buffalo, NY

White powder on a Buffalo basement wall is salt left behind by water moving through the wall, and a free inspection finds where that water comes from.

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  • Salt plus water

    Sherwin-Williams says efflorescence needs both salt and water, and keeps growing as long as both are there.

  • A lot of melt water

    Buffalo gets about 95 inches of snow in a normal year. Spring melt soaks the soil and the wall, then the wall dries all summer, leaving salt behind.

  • Porous old walls

    About 61 percent of homes in the city were built in 1939 or earlier, many on stone or early block that water passes through easily.

What it costs

Typical published ranges for Buffalo. The contractor's written estimate is the price, and the inspection is free.

WorkTypical range
Inspection and written estimate Free
Regrading around the house $500 to $3,000
Seal one leaking crack $250 to $1,000
Waterproof wall coating $1 to $8per sq ft
Interior waterproofing, whole job $2,000 to $6,000
Exterior waterproofing, whole job $7,000 to $15,000

See typical foundation repair prices in Buffalo

What it looks like

The white powder has a name: efflorescence. In Buffalo basements it shows up in a few ways.

Fuzzy white crust

Soft, feathery crystals on the wall that brush off easily.

White lines along the mortar

In block and stone walls, the crust follows the mortar joints in bands.

A ring low on the wall

A white line a foot or two up from the floor, about as high as water soaks in.

Crust around a crack

The salt traces the path water takes through a crack.

Bubbling paint

Paint or coating lifts in blisters with white powder behind it.

Gritty spots on the floor

Salt also forms on the slab where water comes up from below.

To check it is salt and not mold, rub some between your fingers. Salt feels gritty and dissolves in a drop of water.

Why it shows up in Buffalo basements

Water moves through the wall

Block, stone, brick and concrete all hold natural salts. When water soaks in, it picks up those salts. When the water reaches the inside face and dries, the salt stays behind. Sherwin-Williams notes that the crust keeps growing as long as both salt and water are there. So the white powder is not the problem. It is a map of where water gets in.

Wet springs, dry summers

Buffalo gets about 95 inches of snow in a normal year. The melt soaks the clay soil and the wall each spring. Then the basement dries out over the summer, and that drying is what leaves the crust. Many people first notice it in late spring or early summer, after the wall was wettest.

Clay keeps the wall wet

Buffalo sits on an old lake bed with a lot of clay. The U.S. Army Corps of Engineers listed water pressure as one of the four forces on basement walls in Amherst. Clay drains slowly, so the wall stays damp long after rain or melt.

Old, porous walls

About 61 percent of homes in the city were built in 1939 or earlier. Stone and early block walls pass water easily, and many have no working drain tile outside. The National Park Service also warns that salt left in mortar and stone can slowly break down soft masonry over time.

Cosmetic or a warning

Mostly cosmetic

A light dusting in one spot that you clean off and does not come back for a long time. Fix the gutter or downspout nearest that spot.

Worth an inspection

The crust comes back every spring, covers whole walls, or sits in a ring near the floor. Water is reaching the wall every season.

Call soon

The crust comes with puddles, peeling paint, a musty smell, crumbling mortar or a crack that grows. Water is doing damage, not just passing through.

Call now

White crust along a long sideways crack or a wall that leans in. That is water and wall movement together.

How it usually gets fixed

  1. Clean it. Brush it off dry, then scrub with warm water and white vinegar. Avoid harsh acids. This is a cleanup, not a fix.
  2. Move water away outside. Downspouts pointed away, gutters cleaned and soil sloped away from the wall. Sometimes this is enough.
  3. Seal cracks that the salt outlines, if the wall is poured concrete.
  4. Catch the water inside. An inside drain and sump pump for walls that get wet every season.
  5. Seal from outside when the inside drain is not enough or you want the wall to stay dry.

A waterproof coating alone on the inside usually fails if water is still pushing through. The ranges below are typical ranges from national cost guides. Your written estimate gives the real number.

Before the inspection

  • Photograph the crust before you clean it, so the inspector can see the pattern.
  • Clean one test patch and note if and when it comes back.
  • Note which walls have it and how high it goes.
  • Check gutters and downspouts on the side with the most crust.
  • Do not paint or seal over it yet.

Frequently asked questions

What is the white stuff on my basement walls?

It is called efflorescence. Water soaks into block, stone or concrete, picks up natural salts, and leaves them on the surface when it dries. It means water is moving through the wall.

Is it mold?

Usually not. Salt crust feels gritty and dissolves in water. Mold is fuzzy or slimy, often gray, green or black, and grows on wood, paper or drywall. If you are not sure, ask the inspector to look.

Is efflorescence dangerous?

Not by itself. The salt is not toxic. The problem is the water behind it, which can feed mold on nearby wood and stored things and wear down mortar over time.

How do I clean it off?

Brush it off dry with a stiff brush. For what is left, a mix of warm water and white vinegar with a scrub brush works. Let the wall dry well. Skip harsh acids.

Will painting or sealing the wall stop it?

Not for long. Paint does not stop water from reaching the wall. The salt keeps forming behind the paint and pushes it off in flakes and bubbles.

It keeps coming back after I clean it. Why?

Because water is still getting into the wall. As long as there is water and salt, the crust keeps growing. Fix the water and it stops.

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