What causes shadowing on walls and ceilings? The “shadows” I am referring to are the dark lines on the wall and ceiling surfaces that run adjacent to the framing members. I have heard that this is an insulation issue, but want to know what else it might be. These shadows were in fifty year old single story (ranch) that has not been painted in AT LEAST 30 years. It has forced air gas heat. Only observed this shadowing in one bedroom. Thanks.



Very informative. Thanks so much. (Now I can finish my report!) Have a great weekend.


Is a process called “ghosting”. There’s a lot on the Internet about this.

Here are some photographs I took this week concerning that anomaly. It is associated with temperature differences in the ceiling. In this scan you can see warm areas because of current weather conditions, but the condition turns to a cold area during seasonal changes.

good article Mr. Brady!
Looks like we are posting on top of each other! :slight_smile:


Looks like that article is out of “Home Energy” magazine. That’s a good read on a monthly basis. I started getting it in the late 80’s if I remember correctly.

I’m involved as a litigation consultant (possible expert witness) for the building owner in a case against an award winning architect. We’re dealing with ghosting on walls as well as many other items.

The architect used 2x4 inch steel studs in an exterior wall requiring a fire rating. No extra rigid foam insulation was used on the face of the studs to prevent severe thermal bridging. Of course with our cold winter temps and degree days (~7500 DD F*), it was only early in the winter when the ghosting started showing up and became very distinctive on the two storey mezzanine style living room off-white walls by spring. This has been a known energy conservation and nuisance defect within the energy community for many years and we maintain it should have been dealt with in this $350-$400 per square foot home!!!

good information by all nice thread…thanks…Jim

Good info! Thanks.