Have you seen a ghost?

Ghosting… in homes. What is it and do you need to worry about it?

We inspected an apartment building last year where one of the tenants had a concern they wanted to show us. Then they pointed to the ceiling. There on the ceiling, which was painted an off-white color, was a grey stripe. The tenant explained that she had washed it off and it came back. Then she painted it over, and it still came back. It was making her crazy. And she wanted us to tell her what it was and how to get rid of it. We think it was a ghost!

As home inspectors, when we see something like this, we have to do a bit of detective work. We see a lot of strange things in this business, and it isn’t always obvious what is causing the problem. This woman had a stripe on her ceiling that is commonly known as “ghosting”; where you can see outlines of things that are behind the surface. See the picture at right for an example of wall ghosting.Ghosting

“Ghosting” occurs for two main reasons. The first, is the presence of particulates in the air. Those grey stripes are caused by the particulates settling on the surface and creating a stripe. So, why do they only settle on that stripe? There are several reasons this may happen, but the most common is temperature differential. If the temperature is cooler at the stripe, the particles tend to settle out of the air as they come in contact with the surface. This phenomenon is known as plating or condensation. Maybe we should call it condensing plating instead of ghosting. But, enough of the boring science.

Back to my apartment friend. In this case, I suspected that the candles in the apartment had something to do with the problem. Those candles produce soot, and soot particles are heavy and easily fall out of the air, onto a surface. Secondly, during our inspection of the building we learned that there was some piping running to another apartment that was located immediately above the ceiling in her living room. The combination of the soot in the air, and the cooler temperature of the ceiling near the piping was causing the ghosting. And no matter how much she cleans it or paints it, as long as those two factors remain, the stripe will return.Ghosting

In the case of the obvious wall studs shown in the photo above, the ghosting is on an outside wall. What this tells us is that the cold outside air is transmitting thru the studs. There is some (probably significant) heat loss here. Also, there might be a lack of adequate vapor barrier. More information, in the way of thermal imaging or an energy audit might help to solve this problem and to determine how best to fix it. A good solution here might be to install rigid insulation (approx. 1” thick) to the surface of the studs, and then sheetrock over that.

Another common example of ghosting is the plumes of dust/dirt that we see on the outside of a home with vinyl siding. The plumes are usually at vinyl siding overlaps, and most often worse on the north side of the home. In this case, the pressure inside the home is higher (at least at times) so the inside air moves out through the insulation and releases outside at the seams in the vinyl. Once outside, the warmer air contacts the cooler vinyl, and and tends to condense and stick to the siding. When it dries, all you see is a “ghost” of the moisture; the dust and soot from inside the building is now left on the siding. Again, this is not a problem on its own, but does tell us something about the house, especially the positive pressure we are seeing.Ghosting

Should I worry about this? Generally speaking, this is not something you need to worry about. The ghosting itself is not a problem, but it might be a symptom of other problems. If the temperature differential is enough, condensing moisture will settle out, and this may lead to mold and rot.

What are some remedies? Consider that the ghosting is telling you something about the air itself. It is not clean. There are heavy particulates in the air and you are breathing those. If you burn lots of candles, consider reducing that. If you smoke, quit, or at least smoke outside. If you burn with wood, coal, pellets, etc., you may have an inefficient heat source that is causing some soot leakage. Have all your heat sources cleaned and serviced. Or have us do an air test for you, to test exactly what is in your air.

Second, these are most often at areas of temperature differentials. Do you need to improve your insulation in this area? Other options for insulation and ventilation may need to be considered.


KEY POINT TO REMEMBER: Don’t ignore ghosts! Call us to help you understand your home better and live healthy!