Stains on brick beside chimney

Note the dark stains beside the chimney. They exist on both sides. From inside the CS, the band sills were rotted out on both sides. Any clue as to the cause of the stains?

Note the lack of a rain cap. Also, no weep holes. Age of house: 1981.

What do you think?

112607 089 (Small).jpg

112607 089 (Small).jpg

112607 089 (Small).jpg

The stains could be mildew or mold. I would suspect all the framing behind the black is rotting, due to the wall being saturated. The gutter must overflow regularly. What are the 2 black rods next to the chimney? Drainage looks like it is toward the house. Was the crawl space dry?

Jim King

The whole gutter system looks problematic. Notice the splash stains along the full length of the foundaton on the brick just above grade?

Also the downspouts should be kicked out from the house a minimum of 6’.

I would also be looking at chimney cap for gaps, there does not appear to be a proper cap, and I would also be checking the chimney flashings.


You and others have noted the numerous deficiencies evident by the photo.

Is this the north/northeast side of house?

How’s the absence of a cricket working?

BS says moisture moves from hot to cold.

Migrating interior moisture may be a part of the cause where the FP breeches the wall/roof. Not sealed as tight as the rest of the house and the path of least resistance.

Also suspect would be the moisture/vapor barrier installs in the CS and at the sill plate and wall sheathing. Are they present without defects?

Kickout diverters at both sides of the chimney would help to some degree along with the other suggestions.

Bottom line is moisture issues have been attacking this structure for a prolonged period of time, thus the growth/stains.

There was a small cricket present. The flashing looked OK, and from inside the attic, I saw no decay around the chimney. The fireplace was metal, and I wonder if water coming down the flue goes between a seam somewhere and thus rotted out the band sills.

The mud stains on the brick at ground level may be due to a recent gutter install…it may not have had them for a long time. The gutters were working OK…it was raining during the inspection. The lot is not totally flat, and there were no signs of a moisture problem inside the CS. The vapor barrier looked new and was 100%.

I still don’t know why the mildew growth is so heavy at the chimney. But it is suspicious. I recommended a GC to examine the wall structure or an infrared scan.

I think the stain issue has been identified correctly here. To change the subject a little, noticed the height of the power cable above the yard to be too low. Probably should have had a mast installed instead of attaching it at the fascia. I can’t visit anyone’s home anymore for looking for discrepancies.

For those who have not seen the kickout!

There was a mast, but it was installed below the eave. Almost impossible to acheive the necessary clearance when you put the mast head below the eave. I called that out too.

Gotcha. Couldn’t see it in the photo.

The rods are part of a gate frame. Yes the CS was dry, but we’re in a big drought so I don’t know if it stays dry all the time. Moisture barrier looked brand new and that covered up any previous signs of moisture intrusion.

The whole thing was suspicious. I referred it out to a GC to probe the walls from the interior or a specialist with an infrared scanner. Also, the band sills were eaten up with termites (they love moist conditions). So naturally I referred it to a bug man also.

I agree that it is probably mold/mildew, but I think there is a good chance it is on the exterior surface only. I wouldn’t be surprised to learn that something was stored against the wall, and leaning diagonally against chimney - nestled in the corner. It prevented air circulation. I have seen similar in a garage - the interior walls were fine, except for where storage existed next to the wall and at those places mold was quite dense - but, as it turned out, did not exist inside the wall.

Peter, both sides of the chimney have stains like this. It is no doubt mildew/mold, but what caused it? If it has to do with a certain sun exposure, why just around the chimney? Is it a coincidence that the band sills on both sides of the chimney are rotted?

I don’t think it is due to something leaning against the house. It was an old couple who lived here and they didn’t seem to have a lot of possessions. No outbuildings, etc. The lot was well maintained. No junk around.

Frankly, it’s a mystery to me. I appreciate everyone’s feedback.


From what I’m seeing in your pic, the chimney appears to be a masonry type fireplace. I’m thinking I saw an ash dump door in the center of the back wall of the chimney, low to the ground. Is the correct?

If that is the case, my guess’ would be 1) water intrusion in and around probable undersized cricket, kickout flashing, etc.- 2) Chimney has no visible rain guard/cap. - 3) Look into the conditions of the crawl space area for contributing water conditions/problems like gutters/downspout flow, plumbing leaks, perimeter foundation drain design, springs, etc. -4) May need to look further into soils, septic system (if applicable), etc.
Good Luck. Let us know what you finally determine and/or confirm.

Two terms I am not familiar with: CS and band sills.


I can’t tell from the picture but could the chimney be capped completely off with sheet metal? I agree, its a mystery how this occured. Must be water getting into that chimney and staying in there awhile while weeping towards the framing. A gas appliance venting into a capped off chimney could do that.

Peter, CS = crawlspace
Bandsills are also known as band joists that usually sit on mud sills or bottom plates. (Lumber that holds up exterior walls)

Was the building in a flood plain? The tan stain is even on the gable ends of the building. If you blow the picture up there appears to be a similiar stain on the building in the background. Regardless I would bet there is water in the wall behind the brick supporting the “growth” on the brick face.

The chimney wasn’t capped. It had a fine mesh screen over it and no rain cap. I called that out.

I don’t think it would be considered a flood plain. Other houses were near it without those mud stains. (The house you see nearby is a vinyl sided house with a brick foundation.) From inside the CS, I didn’t see any water marks on the foundation walls.

I just called the client and advised him to pull the paneling off the interior walls around the chimney before he buys the house. (I bet the seller’s won’t allow it though.)

Sellers claimed to have had a termite inspection last June that was fine, so the buyer tells me. Probably one of those $55 inspections. :slight_smile:

Joe I think you answered your own question when you stated recent gutter installed. What I observed in the pic was typical for a house with no guttering. Red splash marks along the bottom drip line and water running off of the roof and down the side of the chimney on both sides for a extended period of time. What direction did the house face was the chimney area in the shaded area or direct sunlight.

Looks to me like water from previous or current overshoot at the roof/chimney/eave interface - note that there is little staining on the side of the chimney away form the house opposite and below this point. A proper cricket would be a good idea, but a properly designed kickout to a properly pitched gutter is where I would start. I would want to get up there and take a close look at the roof sheathing and eaves on both sides of the chimney, and also try *really *hard to to crawl the attic to the eaves in this area.