Go Back  DoItYourself.com Community Forums > Interior Improvement Center > Walls and Ceilings
Reload this Page >

Oily blotches coming through plaster walls

Oily blotches coming through plaster walls

Reply

  #1  
Old 10-11-18, 07:53 AM
Member
Thread Starter
Join Date: Oct 2018
Location: United States
Posts: 5
Oily blotches coming through plaster walls

Hello. I thought I would run this by you guys since I am not getting anywhere with it.

My house is 138 years old and there is an angled plaster wall in one downstairs room. Behind the wall is a chimney going from basement through roof. The upstairs room above this room also has an angled wall. The chimney was knocked off 6 years ago and sealed on the roof and is not operational anymore, obviously.

The upstairs angled wall is not having any problems like this but the downstairs wall has something weird going on. Through the paint we noticed some blotchy wet spots. On some of the spots you can see some wear in the plaster behind the paint. In other spots it is just blotchy and wet with no distinguishable "damage" in the plaster behind it in bubbling paint and having it be softened. I had the roof looked at and it was found to not be damaged enough to let water inside to cause the damage.

Upon touching the wet spots on the wall, the dampness feels oily but it is not a colored substance. I took a dry rag and can wipe some of it off by 'buffing' a little but without applying too much pressure. The sheen of the blotches goes away when I do this but it does not dry it and the oily substance returns after a while. I have also used steps to try and dry the wall to no avail. It is no discoloring the paint on my walls, either.

Ok... go. (:
This has me so baffled.
 
Sponsored Links
  #2  
Old 10-11-18, 07:57 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 17,938
It's probably creosote bleeding through from the chimney.
 
  #3  
Old 10-11-18, 08:07 AM
Member
Thread Starter
Join Date: Oct 2018
Location: United States
Posts: 5
I was thinking it was something like that it has probably been there behind the same wall for a good 100 years from what I can tell. The floors in that room are from the 19-teens and they go far under the angled wall. The chimney was last used as an exhaust for the basement gas hot water heater before I switched to electric 6 years ago. That is when the chimney coming out of the roof was removed because of crumbling brick and for its age. The chimney itself would not have been operational as a chimney in the basement for generations. I believe it might have been used with coal back in the day. There is a coal chute beside it coming through the foundation and into the basement... but it is a clear oily substance, at that.

Thanks for the response.
 
  #4  
Old 10-11-18, 08:47 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 44,014
It's doubtful you can wash it off so you'd need to coat those areas with a pigmented shellac like Zinnser's BIN before repainting with latex paint. The BIN should seal the wall enough to prevent more creosote from bleeding thru.
 
  #5  
Old 10-11-18, 09:13 AM
Member
Thread Starter
Join Date: Oct 2018
Location: United States
Posts: 5
I was planning on using Zinnser's BIN after I figure out what the issue is, patching the loose plaster and peeling the latex paint bubbles and sanding and then repainting.

The question I have on creosote is that the chimney has not been used for burning and I am talking the greater part of a century and it was just to heat the basement way back then and there was no fireplace. I believe it was an iron box with a metal grate on the front that the coal was tossed in.

Would creosote be clear when it makes it through the lath and plaster and few coats of latex paint and be shiny and oily like vegetable oil (not as thick)?
 
  #6  
Old 10-11-18, 09:34 AM
Member
Join Date: Jul 2003
Location: California
Posts: 1,730
One other thought. Taste the oily bleed through. My first guess is creosote but it should be dark in color. My next guess is honey. Is it sweet? Maybe you need a beekeeper.
How long has this been going on.? ?Did it only start with hot weather?
 
  #7  
Old 10-11-18, 09:49 AM
Member
Thread Starter
Join Date: Oct 2018
Location: United States
Posts: 5
It started on Saturday, a couple days ago. It was a regular thunderstorm weekend but there was no leaking on the room above it but it was noticed the next day. Last night, I rubbed a plain sheet of paper against some of the the oily spots and there was no color that came off. I have sniffed the substance and it definitely is not honey. I tried to adhere painters tape to the wall to hold the paper up but the tape fell right off and did not adhere at all to the stuff. It smells slightly oily, more like paraffin lamp oil than like cooking or cosmetic but it is not strong at all. I suppose I can lick the wall when I get home. (:
 
  #8  
Old 10-11-18, 10:04 AM
Member
Join Date: Jul 2003
Location: California
Posts: 1,730
In a house as old as yours there are a lot of things it could be. You have suggested some of them. It seems odd that it only started recently. How much gap is there between the top of the flue and the inside bottom of the roof?. I amout5 of ideas but I sure am intrigued . If you figure thisout please let us know what it is. And remember fluids like oil and water run down.
 
  #9  
Old 10-11-18, 10:18 AM
Member
Thread Starter
Join Date: Oct 2018
Location: United States
Posts: 5
There two stories with about 10-11' ceilings. Then above the 2nd floor is probably 6 ft. of attic space to the roof where the chimney was cutoff, patched with plywood and rubber was laid down over it. Then below the first floor is about 3 ft. of basement before it hits the spot where the old iron box connected into it (that was removed). I would say the chimney from flue to roof is maybe 30 ft. Right now it should be the tin duct work running up what is left of it behind the wall as it was used as the vent for the gas water heater. The wall is probably 8 ft. wide and 7 ft. tall before it hits wainscotting at chair rail at 4ft. to the floor.

The other strange thing is that it is not coming through the wall at the ceiling. There are blotches and patches that are playing card size to one side of the wall is probably 4 ft. tall and maybe 8 in. wide. I tried to blow air on there to see if it would dry, too. No dice.

I am going up to the attic tomorrow and see if something is going on up there somehow.
 
  #10  
Old 10-11-18, 11:42 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 44,014
Water always finds the path of least resistance so this substance may be the same. Like TC, I'd expect creosote to be dark. It sounds like we can rule out any water leaks but high humidity has been know to cause issues.
 
  #11  
Old 10-11-18, 03:37 PM
Member
Join Date: Jul 2003
Location: California
Posts: 1,730
What I meant by my question about the distance is how far from the top of the chimney to the bottom of the roof deck? Did whoever removed the chimney take it a little below the roof? I've seen a lot of stains on plaster in old houses, nicotine, crayon bleed through, creosote, some kind of other stain from a gas flue and water stains from condensation. I guess I haven't seen it all. If not honey maybe bees wax? It would have to get awfully hot to melt the wax, though
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes