Mineral Efflorescence: Building Damage Indicators
How efflorescence indicates building moisture problems

Efflorescence Indoors Means Wet or Humid Basements or Crawl Spaces

In our photograph at above left the client is pointing out that water has been entering this basement from the very top of the foundation wall (due to outside roof spillage and bad drainage).

We did not agree with the contractor who told her this was "rising damp" due to wet soils. Rising damp would hardly leap from floor to foundation wall top in a specific narrow area such as this one. Rising damp can't jump.

At above right, in a Poughkeepsie NY home, we see the classic downspout spilling by the corner of the foundation problem indicated by dark water stains and white efflorescence in an inverted "Vee" at the basement foundation wall corner.

Outside, large buried rock may play a role in directing surface runoff towards the foundation, but it makes sense to correct the inexpensive obvious mistakes first.

Efflorescence Indoors Risks Mold, Rot, Insect Damage from Building Moisture

Below you see one of the downspout ends at the same home - spilling right by the foundation wall in an area that does not drain away from the structure.

Watch out: MOLD & HEALTH WARNING: although efflorescence is not mold, it often indicates wet conditions that cause problem mold growth elsewhere in the same building.

Moisture from a damp or wet basement or crawl area will pass upwards through the building riding on rising air through air bypass leaks or even moving simply because of vapor pressure differences: moisture always moves from a more damp area towards a more dry area.

Higher in the building, even in the building top floors, attic or cathedral ceilings, this same moisture may become trapped in or condense in building cavities leading to a costly hidden mold problem.

Attic condensation of building moisture is illustrated

at ROOF ICE DAM LEAKS

and at ATTIC MOLD CAUSES.

In sum, the downspout spillage shown at above right might be causing basement or crawl space water entry (shown above) that in turn might be the source of the moisture found in an attic and dancing there in the form of frost or mold or roof sheathing stains (photo at above right).

You'll need to identify the sources of moisture or leaks and correct them, and depending on other building air quality complaints or health concerns it may be appropriate to inspect and screen the building for problem mold or other moisture or water-related problems.

Where you find efflorescence in a building indoors, you should look for problem mold, allergens, bacteria. Look on organic surfaces - wood, paper, painted surfaces, insulation, fabrics, carpets, carpet padding, or in settled dust and debris. Keep in mind that mold may also be hidden in building insulation that has been wet even it it looks clean.

See FIBERGLASS INSULATION MOLD

Efflorescence Might Explain Damage to Older Building Foundation Materials

Efflorescence and water stains may explain spalling brick or concrete block foundation walls observed in a basement or crawl space. Putting aside for a moment all the whining I've already done above about mold, rot, bugs, and wet-basement anxiety, efflorescence on a masonry foundation more likely to be a cosmetic issue or a moisture diagnostic clue than a structural problem.

Watch out: but the same water around a foundation or under a concrete slab that is causing efflorescence and water stains might also be a source of foundation or slab damage from frost, earth pressure, or in some locales, expansive clay soils. A careful inspection of the building foundation can help put this question out to pasture.

Reader Question: Has the foundation of my building been damaged by efflorescence?

I am sure from your wonderful informative site and comments that the home I'm looking to put a bid on has this Mineral Efflorescence problem. My question is: the home was build in 1950, and I guess may have sand block for basement foundation.

With the walls having been wet and causing the problem could the strength of the foundation be effected? I will fix the leakage if/when I get it,but if the foundation is soft couldn't the home be jeopardized in crumbling apart?

Also, the is only walk-in height to the older part of the home and it appears the additions put on in 1992 can't be inspected correctly due to being crawl spaces. I would imagine there may not be that issue in there as it's newer block but again I understand that water is water if leak is extensive and may be mineral effected too.

They do have a dehumidifier down there and it does not smell musty or damp. Thanks in advance for help on this. - 2015/10/27 Nancy Sustersic

Reply:

I'm not sure what "sand block" is - I use the terms "concrete block", "cinder block" - an older softer form of concrete block, and masons call these building units "masonry block". I infer that the masonry block in your building is relatively soft or perhaps crumbly.

I can't accurately diagnose just what's going on from just an e-text and I'd like to see some photos of the condition of the foundation as well as photos of the home exterior to get an idea what's happening with roof or surface drainage around the home. Our email is at the page bottom CONTACT link.

If there is superficial spalling of the block - less than 3/4" deep into the block surface, and if there is no bulging, cracking, settlement, movement, crushing, then most likely we're talking about a water entry and moisture issue and a cosmetic issue. Below the spalling concrete block foundation wall damage is in my opinion superficial and cosmetic, not structural, but it does tell us

1. that there has been water or roof spillage by the foundation wall
2. there may be water entry inside the basement or crawl area of the building
3. that someone knew of this condition as the foundation in one of the photos was painted with a masonry sealer.

The photos of spalling concrete block foundation walls shown above were contributed by Kingston NY home inspector Arlene Puentes. See ABOUT InspectApedia.com for her contact information.

Most masonry foundations have far more compression strength than needed to support the weight of a typical 1-3 floor residential structure. But if you see actual compression or other actual foundation damage such as I listed above, I'd ask for a repair estimate from an experienced mason.

Limited inspection of crawl spaces is indeed a concern and a topic of debate among home inspectors; while I don't want anyone to go into an unsafe space, I find that the worst problems often are lurking in areas that are hard, scary, or even impossible to access. In that case I

1. look at other clues that suggest hidden trouble such as building movement, cracks, evidence of repeated repair
2. look for the history of water entry that suggests rot, mold, insect problems under the floors
3. decide when the external visual clues + risk mean it's cost-justified to make an invasive opening to inspect where otherwise we cannot see.

See SPALLING CONCRETE BLOCK WALLS & CHIMNEYS for help identifying block foundation damage and for more about spalling concrete block.

See "Dan's 3 D's" in my article

titled FEAR-O-METER: Dan's 3 D's SET REPAIR PRIORITIES

to read more about how to decide when to dig deeper.

Efflorescence on the Building Exterior

Please see EFFLORESCENCE REMOVAL & PREVENTION for examples of white mineral efflorescence deposits on a building exterior on chimneys or foundation and a discussion of the cause and cure for that condition.