Dark Spots on the nail heads and studs?

Vince has sent me an e-mail and would like to get an answer. can anyone help. Thanx Hello! My name is Vince Gallea and I am a real estate representative with Coldwell Banker Pinnacle Real Estate located in Simcoe, Ontario. Recently, I listed a home and it was noted that where the nail heads on studs has dark spots. One wall is a interior wall and the other is a exterior wall. The Seller advises that buring candles is the cause. Could you please let me know if anyone has come across this situation. Please reply to vincegal@flarenet.com With Thanks Vince Gallea

Could be thermal bridging on the exterior wall, which could indicate low levels of insulation.

How old is the house, how is it heated? What are insulation levels. Hard to make an informed guess without more info.

Ghosting… very common… candles… smokers… etc…

good article here…


These may assist in your answers.

I to think it sounds like ghosting if so and the person wishes to paint .
I recommend a sealer over the dark spots then primer over the whole wall to get it well hidden .Roy Cooke sr.

Hello Mr. Crooker:

I concur with the ghosting suggestions.

I was involved in investigating this phenomenon many years ago. At that time, some of my work was being observed by Mr. Frank Vigil who inappropriately took my work, and it later appeared in a national magazine (one of the links provided by Mr. Wand) without any credits to my work. In fact, some of the photographs that appear in “Vigil’s” article are not only MINE, but the individual who is kneeling in one of the photos is ME.

It’s important to note that Mr. Vigil’s article was technically incorrect in many aspects … he should have read my report more closely, and copied it more closely). In any event, I have since been an expert witness on several cases involving the origin and cause of what has now become known as ghosting.

The suggestion of ghosting from candles is almost certainly correct, although the home owner frequently denies their activities are the cause of the problem, usually arguing that they only burn expensive candles. Often times, they are correct in that they are burning expensive candles, but those expensive candles are very frequently poor quality candles made with low quality ingredients and then sold with big end, expensive names.

Jarred candles and scented candles are the biggest offenders, and it doesn’t take much to really create a big problem.

Caoimhín P. Connell
Forensic Industrial Hygienist

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

Without knowing the particulars of the age of house, et ceteras, I wouldn’t rule out thermal bridging.

Please I wish members would endeavour to provide age of home, heating method, etc. We can’t provide proper answer without proper info. Would you buy a car based on age alone? I don’t think so. I would want to know age, mileage, engine size, automatic, standard… et ceteras.


The dark spots on nail heads!

From 1989 to 1992 I was in disaster restoration work repairing homes for insurance companies that had been damaged by fire, water, automobiles, vandalism, etc.

The dark spots are the result of convection. Every time I ever entered a home where there had been a huge fire you could see every single nail head in the place! The surface of the drywall cools faster than the nail heads because they are driven into the stud and continue to wick out that heat still within the studs for hours and even days. The soot from candles, wood stoves or in this case a fire collects at a faster rate on a warm surface than a cold one.

Another example of this same process is the soot that collects on a wall behind and above a charger transformer at an outlet. The air which is heated and rising behind the warm tranformer deposits the soot at a higher rate at that perpetually warm spot of wall.

this is a good example of what he means. the first pic. is my kitchen table that my wife always has a candle on. the next is the outlet in which i use to plug in my nextel charger, while the candle is lit. see the soot.

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Bingo! I bet that air freshener was plugged into that socket which heats the media used to make the fragrance. Hence, convection the same as a transformer from a wall charger. The soot rises and travels behind that heated air freshener at a faster rate than anywhere else and the drywall there stays perpetually warm. Convection. :slight_smile: The same principle I used to encounter in house fires.

I know this is an older thread, but I do have some questions about ghosting. Would the ghosting occur in the room where a candle was burned or could it travel to a room where there was never a candle burned? The dark spots, would ghosting cause them to turn a rust color and then turn black? Does ghosting form square and rectangular shapes? Would ghosting occur only on one side of an apartment and not the other? Is ghosting only possible where a wall and ceiling meet or can it occur in the middle of the room?
thanks so much in advance!!!
If you want to answer, you can answer me in email through my profile.
Thanks so much again!

From the Building Science Corp. artcle in Jeff’s post above…

“Where there is higher heat loss such as at a wood framing member, say a 2x4, the air in the boundary layer right at this spot is colder than the air in the boundary layer just inches away. Well, the air doesn’t bounce around as much in these cold spots which means the tiny particles in the air at these cold spots also don’t bounce around very much. If the particles are not bouncing around very energetically, it is easier for them to get stuck to the surface of the wall. The particles in the air next to the wall tend to “plate out” on colder surfaces.”

[FONT=Tahoma]These descriptions would seem to be at odds with each other. I wonder if increased air velocity from heated air (convection) would cause soot particles to plate out from impaction… similar to the way they plate out on the carpet beneath the areas over which the doors swing.[/FONT]

Most articles seem to agree that the particles are very small and remain airborne for quite a while. If air circulated freely between two rooms, soot particles could easily be carried from the source room into another room where they could plate out on various surfaces.

OK, but what about a room at the other end of the apartment and the “ghosting” in that room is on the opposite side of apparent ghosting in other rooms? (My neighbor downstairs, their back garage wall connects to my back laundry room wall where the “ghosting” has occured. Their back garage wall has bad orange streaks coming down and the paint is peeling and there is very obvious mold) and would ghosting cause rust colored stains (it looks lilke it could be the screws or what they used in the ceiling beams)?

The mold and peeling paint are signs of a moisture problem in the garage.
If the garage side of the wall has excessive moisture on it, some of that moisture will probably move through the wall as liquid via capillary action and as vapor via diffusion. That moisture will eventually cause the nails or screws holding drywall to the studs to rust. That condition could cause rust-colored stains.

Moisture moves from warm areas to cold. If the garage is heated, moisture will move through the wall toward your laundry room more easily. It also moves from areas of high pressure to areas of low pressure, so if you run a laundry room exhaust fan often, that will help pull moisture from the garage through the wall.

So we’re now talking about two different processes. Earlier in the thread we were using the term “ghosting” to describe minute airborne soot particles settling on various surfaces and discussing the conditions that encouraged the settling process.

The “ghosting” in your laundry room sounds like the result of a moisture problem. To correct the problem, first find and fix the source of excessive moisture in the garage.
If after you fix that and repaint the wall you still get staining, it may be airborne soot settling on the wall.

Hey! thanks you guys!! I appreciate all the information! I live in privitized military housing. They are coming out on Monday to actually get into the attic crawlspace area to look at the roof. The second bedroom in my apartment smells musty all the time. When there is alot of moisture outside (Rain, snow…) the smell gets so bad, I have to keep the door closed to the bedroom. There is a spot in the bedroom that is doing the same thing as the other areas. It starts out with a little bit of the dark spots but you can see where the screws or whatever they used because there are orange rusty looking spots. In the other areas the spots turned black. I am looking into the ghosting because that is what they told me it was and even though I think they may be wrong in certain areas, I don’t want to stick with just one thing, even if I am in the wrong. Hopefully we can figure out what it is on Monday.
Again, thank you so much for all your information!!!

OK, head guy for our maintenance here and one of the maintenance guys came out and got in the attic crawlspace. They said they found nothing that would indicate a leak. The told me that the three (in a row) rust spots on the ceiling by the window is the result of this: when they were building this apartment, they were supposed to countersink the screws. They are telling me that they probably didn’t do this and just slapped the mud over the screws. Well, the screws are coming out a bit or something like that and when the humidity is high in the room, the moisture cause them to rust. I asked him, OK, but this is just now happening after 25 years? And apparently the musty basement-like smell in that bedroom is the result of the heater vents being put right under the window. (I live up in northern NY and it gets cold here. We have those heater vents that are along the bottom of the walls by the baseboards) I told them, but it only smells the worst after we have moist weather outside, like rain. Of course, I had to tell them about the “physics” of the ghosting. I said you still haven’t explained how the screws where the ghosting is were rust and then turned black. It takes moisture for that to happen. I told them I am not saying that the stuff isn’t ghosting, I would just like these questions answered. As far as my neighbors garage, they went on the roof to look at it and didn’t even say anything to either one of us about what the findings were. The musty smell is so bad in that bedroom, when my daughter is here, she sleeps in the living room half the time because the smell is so bad. I honestly don’t know what to do now. I plan on calling everytime the smell is bad. The ghosting in the other rooms is not coming off the walls and ceilings. Even with the mild bleach solution they told me to use. OH, and I told them that since I don’t smoke at all in my home and haven’t burned any candles in about 2 years, the ghosting must be coming from someplace else. I really would like some answers, but they want to stick to one thing and not deviate from that. I told them that it could be in the heat vents from people before but they nixed that idea. I told them that I know of people who don’t smoke at all and don’t burn candles but get black stuff all up the walls from the vents. sigh Any ideas would be helpful. Thanks you all!!!


The soot has adhered beneath the ceiling joists…in a room where a lot of candles used to be burned.





Perhpas condensation stains where the cold attic flloor joists are in direct contact with warm ceiling. Especially the pic on the right. Stains are oc.

Erol Kartal
Pro Inspect

They look to be 4 ft apart at the sheet rock seams to me.