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The pics are of structural brick circa 1880 in Baltimore City.

Obviously, the bricks are soft. However, the mortar was very hard and did not crumble very easily under the tip of my screwdriver. This looks like a classic case of using portland cement based mortar to re-point old soft bricks. The reno was done in 2005 and these damaged bricks are near the bottom of the wall. Does this ill effect of incorrect mortar type usually cause damage at the bottom first?

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Around here I see more problems with the "orange" brick than I do with the "pink" type. This is true for old foundations AND chimneys on homes from the 1960's and 70's where antique brick was used. I see the same thing in your pics, so I suspect different composition is the real issue.

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The bricks aren't obviously soft, they're obviously spalled. Why speculate on the cause or pontificate on what you don't understand, John? Note the issue and recommend your client consult an expert. Or as my father used to crudely tell me, "Don't try to fart any higher than your arse."

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Believe me, the report will be calling for a qualified mason to further evaluate. Maybe not in those exact words but....well, you know.

The bricks are the softer type. I'm sure of that. I can tell not only by picking at them but by the sound they make when I knock against them with the tip of my screwdriver. They respond with a dead sort of thud rather then the higher pitched plink you get with the harder material.

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The bricks aren't obviously soft, they're obviously spalled. Why speculate on the cause or pontificate on what you don't understand, John? Note the issue and recommend your client consult an expert. Or as my father used to crudely tell me, "Don't try to fart any higher than your arse."

That seems a little harsh -- or at least presumptive -- to me. I don't think John was asking his question as a prelude to any planned pontification in his report; nothing in his post leads me in that direction. And I don't think speculating on the cause (in this forum) is anything to criticize. I think John was asking a legitimate question to further his knowledge. As I see it, that's mainly what this forum is about.
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Aha!

The Portland-based cement stucco is trapping the moisture in the brick walls. Skin-fired bricks should never, ever have stucco or "Brick-face" (so popular here), containing Portland cement applied.

If the bricks were still exposed on the exterior, the pointing and bedding mortar is lime-based and the interior lime-based plaster was still present, not a single brick would be failing.

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Also...Bill, how exactly does removing the plaster negatively affect the situation?

The bricks on the interior wythe were specifically selected for interior use because they were the furthest from the heat source in the kiln (underfired). The skin is inadequate for the face of the brick to remain exposed. The moisture that is in the brick wall now only has one path out - inwards, taking out what little skin was on the brick.

It's an epidemic. Folks buy expensive brick homes in exclusive historic areas, strip all the plaster to expose the brick, then ask "why is there constantly red dust all over my home?"

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Would these stains on the exterior wall fit the rising damp idea?

Also...Bill, how exactly does removing the plaster negatively affect the situation?

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Homes around here are too new to see structural brick very much at all, but I'd have to think that a plaster layer would help diffuse moisture so that it could evaporate evenly.
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The moisture that is in the brick wall now only has one path out - inwards, taking out what little skin was on the brick.

I understand the mechanics of the moisture. What I don't get is how does the moisture spall the skin off the brick. Or did it spall just because exposing it allowed people to damage it with chairs, furniture, etc?

Marc

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I understand the mechanics of the moisture. What I don't get is how does the moisture spall the skin off the brick. Or did it spall just because exposing it allowed people to damage it with chairs, furniture, etc?

Marc

It's caused by using the wrong type of mortar for later repointing.

http://www.oldhouseweb.com/how-to-advic ... onry.shtml

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The bricks aren't obviously soft, they're obviously spalled. Why speculate on the cause or pontificate on what you don't understand, John? Note the issue and recommend your client consult an expert. Or as my father used to crudely tell me, "Don't try to fart any higher than your arse."

That seems a little harsh -- or at least presumptive -- to me. I don't think John was asking his question as a prelude to any planned pontification in his report; nothing in his post leads me in that direction. And I don't think speculating on the cause (in this forum) is anything to criticize. I think John was asking a legitimate question to further his knowledge. As I see it, that's mainly what this forum is about.

Kevin, you're very likely right. In any event, I was unjustifiably harsh on John. Inspectors who say things they don't understand or cannot justify are a particular pet peeve of mine because they are, in my opinion, a major contributor to the downfall of our profession.

But none of that is John Dirks' fault. John, I apologize for being a jerk in my last post. I owe you an adult beverage of your choice, and I hope you take me up on it when our paths cross.

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The bricks aren't obviously soft, they're obviously spalled. Why speculate on the cause or pontificate on what you don't understand, John? Note the issue and recommend your client consult an expert. Or as my father used to crudely tell me, "Don't try to fart any higher than your arse."

That seems a little harsh -- or at least presumptive -- to me. I don't think John was asking his question as a prelude to any planned pontification in his report; nothing in his post leads me in that direction. And I don't think speculating on the cause (in this forum) is anything to criticize. I think John was asking a legitimate question to further his knowledge. As I see it, that's mainly what this forum is about.

Kevin, you're very likely right. In any event, I was unjustifiably harsh on John. Inspectors who say things they don't understand or cannot justify are a particular pet peeve of mine because they are, in my opinion, a major contributor to the downfall of our profession.

But none of that is John Dirks' fault. John, I apologize for being a jerk in my last post. I owe you an adult beverage of your choice, and I hope you take me up on it when our paths cross.

Jim,

I know you mean good and I understand all the hard work that went into you learning what you know. I think the general message of your initial comment has validity from a professional standpoint. I did not take it personally. The pokes keep us on our toes and that's a good thing overall.

As an inspector, I'm one who is always trying to learn as much as I can. Like many, sometimes things need to pass through more than once before they sink in. I like to share what I know with clients. I talk alot at inspections and I'm sure some of you might think that some of my report comments are a bit winded.

I know that simply recommending experts to figure things out is a way to do my job. However, I sometimes feel it's a slimy way of just kicking the can down the road to someone else. When I can give what I believe is valid information to my clients, I spend extra time doing it. I not only want them to know what is wrong, but also what kind of questions they should be asking the "professionals" who'll be following up.

Jim, if our paths ever cross, I'll take a Heineken bottle (no glass). However, I doubt you'll get away with buying only one. [;)]

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John,

Next time Bill Kibbel teaches a class on Inspecting old houses, you need to attend. Or read everything he has written on the "Old House Web".

When things, like you posted, come up on my Inspections and I don't want to write a long explanation in the Inspection Report, I direct the reader to Bill's site (I know it is not his site, but he seems to have the most articles posted).

TIJ should put together a 2 day class on wall systems with Bill leading the Experts in teaching the great unwashed. Chicago would be a good location , Kurt could host it and suggest the best places to eat.

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John,

Next time Bill Kibbel teaches a class on Inspecting old houses, you need to attend. Or read everything he has written on the "Old House Web".

When things, like you posted, come up on my Inspections and I don't want to write a long explanation in the Inspection Report, I direct the reader to Bill's site (I know it is not his site, but he seems to have the most articles posted).

TIJ should put together a 2 day class on wall systems with Bill leading the Experts in teaching the great unwashed. Chicago would be a good location , Kurt could host it and suggest the best places to eat.

Actually, I did attend a presentation Bill gave in PA for an ASHI CEU event. It was very informative. I'm sure the presentation just scratched the surface on what he knows. I'd love to be as knowledgeable as him. He and others on this forum are truly an asset to this forum and to our profession.

I've seen the assault on the historic masonry other times in the Baltimore area. I should have nailed it the second I saw it. I knew it wasn't right at the beginning. It just took a little time and help to gather things and understand the big picture. I'm happy to say the understanding came clear before the report was sent.

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Sometimes I see the same thing as John - old Baltimore home with brick now exposed that was at one time covered with plaster. Most time the brick has nothing, but sometimes the bricks (and mortar joints) have a clear coat of some type of shellac or varnish. What do you think that sealing the brick will do to the brick over time?

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Screw it up.

The problem cited is epidemic in all masonry. Incompatible mortars, and it's not just historic stuff. The engineers love the high compressive strength mortars, but they simply aren't compatible with all brick.

The parging we see so often was, at one time, a lime based preparation that "nourished" the old masonry, a moisture barrier (sort of) and acted as a sacrificial layer for the valuable underlying brick. It's been reinterpreted as a layer of "waterproofing" that really screws stuff up.

Forget portland cement, or at minimum, apply it sparingly in any mortar mix. Think lime.

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