InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
Moisture & dark efflorescence, stains, or "growths" on building surfaces:
Red or Brown Building Stains & Deposits that are not mold:.
Here we illustrate and explain the cause & cure of reddish brown or pale yellow bubbly surfaces on walls, especially masonry walls or on masonry chimneys, caused by leaks & moisture - efflorescence and sometimes creosote leaks.
When investigating a building for a mold problem, you can save mold test costs by learning how to recognize Stuff that is Not Mold or is only Harmless Mold but may be mistaken for more serious contamination - save your money.
Our photo at page top shows white fluffy crystals of mineral efflorescence near the bottom of a poured concrete foundation wall.
Because some clients have on occasion sent samples to our lab that really should not have been collected, much less looked-at, I provide this library of photographs of things that are "not mold" and don't need to be tested.
These are substances that you can easily learn to recognize in buildings.
Save your mold test money, and increase the accuracy of your mold contamination inspection or test for toxic or allergenic mold in buildings: review these items to learn recognize non-fungal materials or even possibly harmless cosmetic "black mold" often mistaken for "toxic fungal growth."
These photos of ugly reddish brown and white bubbly "growth" on a plastered masonry wall were sent to us by a reader.
This stuff looks like terrible mold but it's probably not mold at all. We won't know for sure without testing the material or inspecting the building.
But it sure looks like reddish-brown salts left behind by water and moisture passing through a masonry wall or a plaster wall, evaporating from the wall surface and leaving behind all of the crud that the moisture picked up from the wall itself as it passed through.
We often find this darker colored wall deposit on older buildings built of brick and stone whose interior wall surface is plaster applied directly to the masonry wall. We also often find this wall "growth" when water has been leaking in a plaster wall cavity.
Plaster is so alkaline that it is not as friendly to mold growth - it's not "mold proof" as mold may grow on or in paint or even on or in organic material in or on the plaster.
More red stains found indoors are discussed at STAINS on INDOOR SURFACES, PHOTO GUIDE
Take a look at this closeup (above left) of peeling paint on a foundation wall in a basement. The lumpiness of the surface tells us that this wall has been painted a number of times, painting over a rough concrete or concrete block surface.
In the center of the photograph (above left) you can see where paint is falling away and the gray concrete or concrete block is exposed. At the upper left corner especially you can see rounded bubbles of material that looks as if it is "growing" on this foundation wall.
The author's hand (photo above right) shows a combination of peeling paint, deteriorated masonry surface, and mineral salts all left behind as water and moisture have been passing through the building foundation. There is a water problem in this building and a moisture problem, but the stuff on the wall and in hand is not mold.
These pictures shows combination of peeling paint and yellowish-white mineral salts left behind as water is passing through this wall as moisture or as actual liquid water.
The moisture is both pushing paint off of the surface and also leaving behind salts of various minerals that were dissolved out of the wall as the moisture passed through it. When water evaporates from a surface it leaves behind minerals that were dissolved in it.
In our photo at above left we see bubbling paint and plaster on an interior wall surface - an indication of the "lift" power of the mineral crystalline salts formed as efflorescence under a paint layer.
White powdery stuff appearing on a brick chimney may show up indoors or outside (photo above left). Brown stains leaking out of any chimney (photo above right), whether masonry or metal, may indicate a dangerous condition - prompt inspection is needed.
We find these stains on concrete block or "cinder block" chimneys as well, and occasionally on stone chimneys.
Brown stains on a chimney wall may also show up indoors or outside (photo above right). The brown stains are probably from creosote or soot washing out of the chimney interior flue and leaking into the attic through the chimney wall. This chimney needs immediate inspection and repair.
In either case we recommend that you promptly hire a professional chimney sweep to inspect the condition of the chimney including at the rooftop and inside the chimney flue. Water leaks into a masonry chimney can damage it and make it unsafe both structurally and with respect to leaking dangerous flue gases or even sparks that could cause a fire.
See CHIMNEY INSPECTION DIAGNOSIS REPAIR for details.
Our home was built in 1915, and probably hooked up to the combined sewer that was in place after 1906. Their mistake, in hindsight.
We have a sewerage district that has wisely begun uncoupling those old connections where separation was not required.
Walked down to the basement today and found a bunch of these little deposits. They’re moist spots, with maybe some efflorescence, but a gray, dusty/powdery layer over it. All over, various sizes/density. Have not noticed them until now.
[Click to enlarge any image]
I can’t tell if this is:
1) Basement crud (lint, fur, dust) collecting on moist spots
2) Moisture that is seeping up and generating mold, on top of efflorescence
3) some other gross accumulation
I don’t notice a smell at all, so I would rule out animals.
I opened the basement heat vent a few weeks ago, which I think was a mistake. The dehumidifier shows 40-45 humidity, and has all winter. That humidity and the temp seems way too low to generate/support mold growth. - Anonymous by private email 20 March 2018
The photos are a bit blurry and of course a lab analysis is a much more accurate answer to your question, but what I see looks to me like efflorescence with possibly some green mold growth.
Mold does not much like raw concrete, but mold of many species will grow on organic debris that might be on concrete, more so if it's enriched by sewage or sewage effluent. That means there could be bacterial hazards as well.
It would make sense to clean and sanitize the surface, then give some attention to
1. inspection of the sewer line to be sure it's intact
2. steps to dry out the area - see WATER ENTRY in BUILDINGS - home - as a reasonable place to choose among diagnosis and remedial steps
I learned a lot by spending some time on the site last night. I'll do some clean up and dry out this weekend and see what happens.
We are looking at disconnecting/capping the downspouts that feed into the foundation drain from the roof, as well as a French drain in the back where a slope comes down to the house from the rear of the lot (high point).
There was a known sewer backup through the floor drain from a combined sewer a few years ago, and there are water marks around the columns, but the dark spots here are moisture welling up through the floor (which is painted green).Sorry the images were so large, I attached a smaller one with a bit better resolution.
Thanks for what you do, this kind of information and advice is so helpful.
Your message reminds us of the difficulty of guess-diagnosis of building conditions from afar. In virtually 100% of the cases in which I haven't visited the property I have found important data that significantly amended or improved our diagnosis over what we might first have seen by email.
For example it's a classic mistake to connect downspouts conducting roof drainage injury foundation drain system. That overloads the foundation drain or the life of the building on the foundation drain system becomes clock with those conditions send significant amounts of water under the foundation under the slab.
Heading to the previous sewer backup means we've added nutrients that would invite both balding bacterial growth. I think you're quite right start outside getting roof runoff well away from the building. And you want to clean sanitize the slab.
Looking again at your photos I think there could be fungal growth along with of course other substances, though the first best guess remains efflorescence You could probably confirm efflorescence by shining a bright light obliquely along the substance to look for shiny crystalline structures that will be more obvious under a hand magnifier.
There are as well mold species that will grow on almost anything, but on concrete where I find mold (such as an old concrete basement floor) usually the mold is growing on some organic deposits: possibly in this case sewage remnants?
A cleanup that addresses a sewage backup would probably be fine for removing the mold too; I'd follow any sanitization or disinfection by a careful inspection to be sure we're doing all we can to keep the area dry
. Aside from the water entry in buildings link I gave before, if you haven't done so, see the steps at BUILDING DRY-OUT PROCEDURES
and at WET BASEMENT PREVENTION
MOLD & HEALTH WARNING: although efflorescence is not mold, it often indicates wet conditions that cause problem mold growth elsewhere in the same building.
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.
In our photograph (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.
This discussion has moved to EFFLORESENCE REMOVAL & PREVENTION
Continue reading at EFFLORESCENCE SALTS & WHITE DEPOSITS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see MOISTURE CONTROL in BUILDINGS - home
Or see STAIN DIAGNOSIS on BUILDING INTERIORS - home
Or see WATER ENTRY in BUILDINGS - home
Or see this
Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
(Apr 20, 2014) linda haytop said:
tan fuzzy stuff on inside of shed roof. 6" 'strings' hanging down with black half moon shaped things. dripping out sticky substance. clusters of cream balls. help! what is it?
Linda I can't imagine from just the text note. Use the CONTACT link found at page bottom and send me some sharp photos and I'll comment further.
Watch out: if this is termite damage. You'll want to check out: TERMITE DAMAGE INSPECTION
(June 4, 2014) Anonymous said:
I have what appears to be efflorescence on a home interior rock wall (fieldstone?) surrounding a fireplace. Most of the deposits are white but there are some darker patches above the fireplace (not used for years) where the stone has started to deteriorate. I brushed and then vacuumed all areas which improved the appearance. This problem has been going on for at least 4-5 yrs and the house has been closed up each winter for many years
I'm not sure about products to clean it like Magic Acid, etc. because I'm concerned that cleaning materials may discolor the stone and make it look worse. The mission is not to solve the root cause but to improve the appearance. Suggestions are greatly appreciated.
From Neil Hochman NH83151@aol.com
Correction to Anonymous/Neil Hochman post:
The fireplace wall is NOT fieldstone but a greyish/blue stone of uncertain composition laid out brick style surrounding a bluestone fireplace hearth not affected by the efflorescence.
(June 8, 2014) Neil Hochman said:
RE: Earlier post about efflorescence on indoor fireplace wall. The first comment was accidentally send under Anonymous and has disappeared from the thread. Need to remove efflorescence patches from the stone wall described below but am worried about what product to use as staining might result? Powder has been brushed off and vacuumed. What do you recommend for safe cleaning? Thank you.
Neil: long time since we've chatted - do you recall sleeping on the Murphy Bed at 3 Willowbrook? Or is this a different Neil?
Anyway, check your chimney cap, crown, sides, and flashings for leaks - any of which might make the chimney not just leaky but unsafe.
Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website