Thread: Chimney brick spalling

Here are some interesting photos of chimney damage to a 1970's house. I know that the spalling is an indication of soft brick where moisture penetrates the surface, then freezes and causes the face to spall off. The moss also indicates moisture. The fact that it's concentrated below the sloped cap suggests that the moisture might be entering from the cap. However, there is a crack in the chimney above this area, and I can't figure out the cause. I haven't been on the roof yet (these photos were sent to me) but I'm guessing that there might be cracks in the cap, allowing water to enter. Any thoughts on cause and repair?

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The shoulder slate does not have enough overhang to drip water properly away from the chimney face, the lack of proper step flashing is allowing water in and under the shoulder slate also causing damage.
Also I would suspect that the upper flashings are leaking causing water to penetrate along the edge and freezing and cracking and, I would want to go on that roof if I were you.

they should have installed vinyl siding over the brick chimney.
then you couldn't see the spalling and cracks.

Are there no gutters? I can't see them in the pictures.... if not, that explains a lot. More water to freeze/thaw = more damage to the brick. 1970 is not super old when it comes to masonry. The heaviest damage seems to be downhill on either side of the chimney where the most water will pass (roughly half around each side of the chimney).

Matt,

Good catch. I didn't attached an overall photo of the house. It's a two story, with a relatively low slope (looks like about 4:12) hip roof. The chimney is at the center of one end of the house, but yes, the roof does slope towards the chimney and there are no gutters.

That would explain why the masonry is in worse condition than would be expected, particularly where there is the highest concentration of water passing over it. There is definitely enough damage to call for a repair.... and maybe some gutters

in my previous smart axx post, i noted the vinyl siding.
i wonder what is being covered up, water damaged siding...

Wayne, when u say the step flashing, or lack thereof, do u mean between the shoulder slate and chimney? And how would that be done properly. Under or on top of the shoulder there. And should it have been inserted right into the mortar? Thank you

I finally managed to get to the site. Attached are a few more photos. Note that there are also cracks higher up on the chimney. It looks to me like it's ice damage, probably exacerbated due to the lack of gutters

One other thing I found interesting. The flue had been cut down in height and the brick extended to allow for installation of a stone cap. See photo. I don't see how this could be related to the damage, but I thought it was interesting. They were obviously having some problem with moisture or drafting

Brian, Yes. The counter flashing should be set into the joints and grouted. Step flashing tucks up under the counter, Sometimes a curf is cut in a straight line. And yes I agree that the constant water pouring off the roof at the side of the chimney would get that area so wet that when it froze everything exploded.

The counter-flashing in the second photo well may be properly set (can't really see from the picture). It's somewhat common to caulk the point where this flashing protrudes from the masonry.... I'm not sure why other than to fool the HI. I guess it gives a 53 year life on the flashing rather than 50 (caulking fails after 3 years, flashing then takes over and lasts 50)

As for the first photo, I'm not sure what's going on there but it doesn't look like properly set flashing.

Wayne and Matt thanks for the replies, much appreciated.

Thats not an acceptable cricket either is it? The water could come off the chimney and get back under those shingles and potentially leak through the sheathing couldn't it?

Damage is very interesting, my first impression is moisture damage for all the reasons already mentioned, however I would not rule out other possible causes, lightning strike, thermal expansion from the inside.
Two questions. 1 Which way does this chimney face, N.E.S.or W?
2.What part of the country are you in?


Kevin T Stewart
F.I.R.E. EDC

Originally Posted by Kevin Stewart

2.What part of the country are you in?

Kevin,

Look in the upper right of his posts and you will see: Location: Massachusetts

If you would, add YOUR location, simply click the 'User CP' link just below the 'InspectionNews' logo, left-most menu bar link, and type in your location, city and state works best for us to know where you are, thanks ... unless you are in as small of a state as Massachusetts, then I guess they just say Massachusetts as that must only be the size of one town?

I thought only Rhode Island was that small, but I guess the people who live there know best.

Cool, thanks did not know it did that.

Kevin T Stewart
Richmond VA.....a bit bigger than MA

That's an interesting damage pattern, and I wouldn't rule out anything at this point. My first thought was lack of gutters and kick out flashings putting a lot of water down the edges of the chimney


of the chimney:



but that large area of vertical damage is present on only one side of the chimney, for starters I would want to see the chimney cap and a chimney cam of the flu in that area.

Mike,

It's probably not clear in the photos, but there is cracking on both sides of the chimney, immediately below the fascia