# Why is this brick suddenly falling apart?



## dakzaag (Jan 6, 2009)

I looked at a Church the other night, they want to wash and seal it. Right by the front door the brick are spalling apart. Why would it do this after 100 years of excellent service?

Here is the front.










Here are a few pics of the brick breaking up.










What I like about this shot is the ease of access we have here.:w00t:










I think it is either caused by salting the steps in the winter time, or someone cleaned the door jams with acid and got it on the brick.

The only spot where the brick are spalling is right around the front door. The rest of the church is in really good shape. 

I usually wouldn't recommend a sealer, but they are pretty sure they have been sealing it about every 10-15 years. The contact guy is checking to see what their records show as far as past products and procedures. 

Here is a shot from the side, notice the top of the stone on the side entrance.









I want to recommend a sealer and a procedure to stop the decay at the front doors. If I had to guess what happened, someone acid washed the front around the doors and didn't get the acid out of the brick years ago. Now those chickens have come home to roost and the brick are falling apart. 

I will find out if they know any more about what has been done to the structure if their records are detailed in any way.


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## superseal (Feb 4, 2009)

How are the winters there? piling of salted snow? could be an acid issue I guess...maybe rising damp - freeze/thaw, incompatible re-pointing mortar...probably all the above plus some.


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## JD3lta (Nov 22, 2009)

Weird, calcium chloride salts would tear up the concrete stairs as well in excess. This ought to be a good one. I don't know if you can catch the culprit.


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## dakzaag (Jan 6, 2009)

I'm guessing that brown exterior carpet is hiding a nasty cement step. The rest of the steps looked ok though...

Our winters are typical midwest. Occasional piles of snow but this area is often on the edge of freezing weather, we get a lot of overnight freezing and thawing during the day. 

A lovely combination of freezing rain and sleet can often be found also. It really is adorable when our electricity is out for several days from power being down.


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## superseal (Feb 4, 2009)

dakzaag said:


> I'm guessing that brown exterior carpet is hiding a nasty cement step. The rest of the steps looked ok though...


 I noticed that myself :shifty:


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## NJ Brickie (Jan 31, 2009)

Is the door newer? I might say expansion of the door if it was only against the door jambs, but I see you have a few spalling on the wall with no door.
If the door is very tight in the opening I could see expansion popping the faces of those old soft brick.


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## dakzaag (Jan 6, 2009)

Undoubtedly the door is a replacement, not sure when. Seems like the bare aluminum look was really popular in the 70's. 

The doors face the west so they get the strongest effect from the sun. I suspect we have a hit and run bandit with a gallon of muratic acid. :furious:


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## Tscarborough (Feb 25, 2006)

It looks like it was recently repointed, probably with a cementious mortar over a lime mortar. Always a bad idea, and likely to trap moisture in the brick. It will come out somewhere, and my guess it was through the face of the brick.


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## dakzaag (Jan 6, 2009)

Here are some more pics. I agree, it was repointed in the past, but probably 40-50 years ago. I have seen a lot of structures in this area where the lime mortar was falling out and replaced by portland based mortar. 










Not a lot of damage except below the belt level.




























If the damage was a result of the tuck pointing with portland, wouldn't there be more damage all over?


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## superseal (Feb 4, 2009)

I'm beginning to think some type of excess concentration or dwell time of cleaning solution e.g. muri or some other restoration cleaner. That brick is too damn clean be be 100 years and appears acid etched in some areas.

Most likely though, a combination of events .


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## Tscarborough (Feb 25, 2006)

It would only be in areas with moisture issues, but if it has been tucked that long it is not that.


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## EES (Jan 4, 2010)

Since it's near the doors, is it possible that these were areas where lots of people would regularly kick off their muddy/slushy/salty shoes before entering the church?


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## dbrons (Apr 12, 2010)

> That brick is too damn clean be be 100 years and appears acid etched in some areas.


I wonder, could it have been sand blasted?


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## tgeb (Feb 9, 2006)

My thoughts are that ice melt is tossed onto and tracked onto the carpet all winter.

The snow melt does not wash the ice melting products out of the carpet, so every time a heavy rain comes through, the salts are dissolved and splashed up onto the brick work were they do their thing till the next rain.

Probably takes till June to get all the ice melt washed out of that carpet.

Just a thought. And it would explain why it did not happen earlier, (prior to the carpet).


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## dakzaag (Jan 6, 2009)

Salty carpet would work for me. The guy mentioned that the church was cleaned several years ago, but didn't know what the process was. I told him to find out. 

If by chance they blasted it, then that would give the salt splash an opening to attack the brick. The carpet is not that old, unless they replace it regularly. 

Nice observations, I think I will push for more information about the previous treatments this building has had. Very pretty church, I don't want to be the guy that gets blamed for messing it up.

Notice how one of the bricks behind a pillar is breaking up. It should have been shielded by the pillar.


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## Diamond D. (Nov 12, 2009)

Agree with Tscar, it is obvious from the pictures that it has been repointed all around the sprawls...too much cement in the mix.

I think if it was from salts, from boots, de-icer or rain splashing on the salty carpet the joints would be affected first and there would be more wide spread damage...just my opinion.


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## Willy is (May 20, 2010)

Just my take on it. The brick is very clean. I'd guess that it may have been blasted a while ago and repointed some years ago. The mortar looks appropriate to me. The entire structure looks pretty clean. I'd guess that the lime mortar mix was right.

There is a distinction between the regular brick and the repair of the spalled brick. The patch job is the result of the spalled brick, not the cause of the original spalling, my guess.

Blasting the brick may have lead to the damage of the brick. My guess is that the lower and more visible areas may have also gotten more cleaning or protectant. It could be that a sealant could lock in moisture and cause a problem. If you knew the history you would have a better idea but.....the building is very very clean, no?

I think a close visual inspection would show signs of blasting and so might the soil around the area.

willy


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## GrasshopperPete (Oct 12, 2008)

I agree with Tscar and Diamond...the newer mortar used to repoint contains more portland cement and can withstand higher compression from the bricks above.

This mortar will not yield as easily as lime, which withstands a lower compressive weight before yielding (that is what it is supposed to do).

Mortar is sacrificial, it is supoposed to give before the brick does...then you repoint which is theoretically more economical than replacing brick.

The portland cement will not yield as easily, so the face of the brick, which is softer than portland cement, will shear off.

You`ll prob need to use (0 part portland) 1 part hydrated lime to 3 parts sand.


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## RZB (Sep 30, 2008)

I don't know alot about restoration masonry, but could they have filled in weepers when they did the pointing? I don't know if buildings this old even had weepers but that could cause water to build up behind the lower brick and spall them.


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## Tscarborough (Feb 25, 2006)

There are no weeps on this type structure because there is no cavity. This is structural brick masonry, and it relies upon mass to limit moisture penetration. 

That is to say, with a modern cavity construction the veneer is assumed to leak, drain into the cavity and out the weeps. With structural masonry, moisture was expected to penetrate the wall during rainy cool periods, and leave the wall during hot dry periods. The wall in this system, of course, has to be thick enough that the moisture does not penetrate all the way through the masonry mass to the inner wall (cold, clammy castles, as an example) during the time of year when moisture is penetrating. 

This is also why it is important that tuckpointing is done with matching or softer mortar.


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