puzzled

I live in a house that was built in the 1920s. It is stucco, the chimney is on the outer wall and is also wrapped in stucco, the wall makes an L at the chimney and there is a small closet that backs up to it. Shortly after moving in 10 years ago, I noticed little droplets of brown liquid oozing out the plaster wall over the fireplace. Worried female that I am, I wiped them away. I thought maybe (guessing!!!) it had something to do with the paint; I covered it with Kilz primer. It gets worse every year, with more dampness, and now the plaster wall is starting to crack. The fireplace has a decorative gas log set in it, which I haven't used for a number of years. The furnace, which is old, and oversized is in the basement. It vents directly into the chimney which is unlined. I had a chimeny cap put on about 6 years ago. I can go up into the attic and look arround one half of the chimney and roof line, no signs of any water. The other side backs to a room and there is no sign of water there. I can also look down onto the top of the closet area which is also dry, the reason I mention the closet is because their is a damp spot in its lower corner which is right against the fireplace. I called a furnace company, wondering if the condensation in the furnace might be causing a problem. He was of no use. Although the last individual that came to do a maintenance check on the furnace said it could be something like that.

Do I call a contruction person or a chimney specialist? Or a pasterer to fix it and hope for the best? Any thoughts would be greatly appreciated. I should mention that the wall feels dry in the summer. The wetness comes in fall when the rains come. (I live in Washington St so there is a lot of rain). This is also when I begin using the furnace though so it is hard to link it more to one than the other. But it seems worse when it has been raining alot.

joan518

Have you thought of checking the chimney flashing between the chimney and roof?

ccarlisle

Call in a chimney specialist; sounds like the moisture is getting down the chimney from a spot it shouldn't be and there's a chance the cap isn't right. Have that fixed before you do any plastering.

puzzled

Thanks. Do you mean that the water would be coming out the wall from inside of the chimney? I don't think it can be coming down along the outside of the chimney because I can see most of the area where the roof and chimney join from the attic, and there is no water. I had the problem before I got the chimney cap, I thought the cap might help. I'll try your ideas.

itsreallyconc

just replaced the chimney cap on the house across the st after the owner mentioned there was wtr dripping into the fireplace's firebox during recent rains,,, over the yrs, it had crk'd allowing wtr to penetrate the space 'tween flue liner & brick facing,,, repointed the brick, installed lead flashing ( the old-fashion'd way ), washed brick, & treated w/silicone siloxane.

her brick was also wet under the roofline on the back patio.

pay attn to carlisle's posts.

buletbob

If there is no water dripping into the fireplace box, Then there is a considerable amount of condensation building up in the chimney, if it was built in the 20's most likely there is no flue liner installed there could be cracks in the mortar or even in a liner if installed. your probably going to have to have the chimney lined. Your best bet is to call a chimney expert, they will be able to send a camera down there to see whats going on. BOB As mention above have the flashing checked around the roof and chimney.

kawendtco

if you have the option to reroute your furnace flue i would do that or at the very least install a liner that will carry all of the moist poisonous gases out and into the air above. a large dinosaur furnace like you are describing puts off an amazing amount of moisture.

also where the roof meets the chimney, have a competent roofer check your step flashing. the flashing is probably the original and may be corroded away in spots allowing for water intrusion.

get all of this done and make sure the wall in your hearth room is staying dry, after all rains and during furnace/water heater use. i would use a moisture meter to check the content before and after.

good luck

stuart45

Brown staining on the chimney breast is quite a common problem where I live as most flues were unlined until the late 60's, most stacks were built of softish bricks and the climate is a bit on the damp side. It can be condensation from the fires, or water penetrating the brickwork and running down the flue and coming through where any of the sand/cement parging is cracked or missing.
As there are usually hygroscopic salts on the wall of the flue the dampness takes these into the brickwork and plaster. These will attract condensation at a R/H as low as 50%.
When the breast is replastered 2 sand/cement coats with added salt retarder/waterproofer are required before a plaster skim, or the salts will come back through and cause more dampness.
Builders often used to render chimney stacks with damp problems, but this has now been found to sometimes make the problem worse as once the cracks appear the water enters and can't escape.
If the stack is rebuilt we always put in a lead DPC to stop the damp.

itsreallyconc

missed the ' brown spot ' part,,, could be creosote suggesting crack'd flue tile or ' holidays ' in the mortar,,, there are flexible flue liners avail - just something else to consider.