Crumbling Bricks

Does anyone have any experience with bricks crumbling apart? The bricks in this chimney (not all of the bricks but several) would crumble when I touched them.

I reported this to the client but my answer didn’t fully satisfy me. I told him I was not sure why it was doing this (sometimes you just have to admit it)but my theories were because the brick was painted moisture was held in and the fact that it was very, very old brick. The house was built in 1965, but I believe the brick was probably 30’s or 40’s

There were old red bricks in the yard with the maker’s city stamped in it (common in TX) as Groesbeck. I believe the chimney was made with these bricks; however, not all of the bricks were in this condition.

Any clues? Thanks in advance.


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I had to recommend complete removal of three chimneys once on a 100 year old house. I have not seen bad bricks on houses newer than that. Bad mortar would be possible. If its that bad don’t just recommend further evaluation, they have to be removed.

I did stress that the chimney is compromised and could fall. I’ve since tried to do some research on Groesbeck bricks to determine when the factory was operational. I’m seeing as far back as the late 1800’s. If these are the bricks used on the house, they have a substantially older date than 1965.

Was there ever a TV antenna there?


The bricks appear to be spalling. This is caused by moisture entering the brick. Water can enter in a number of locations, but most likely through cracks in the chimney cap or in the mortar holding the bricks together.

Good site David.

Some older red clay bricks were not “fired” as much as they should have been which causes them to hold moisture and break down much quicker than others. I bought a bunch of old brick from an old building that was being torn down from the early 1900s and found this to be true. Many bricks were fine when installed, but started to break down afterwards. I really noticed it on the ones we put down in the ground for a patio…they held in moisture from the ground, and then were subject to freezing and literally crumbled into powder. We had to replace 10-20 bricks each year on the patio. The ones that were installed in the fireplace’s faired much better because they were vertical and stayed much drier.

I don’t think painting had anything to do with deterioration…if anything, it may have helped provide a moisture barrier to prolong their life. **PROVIDING **the painted surfaces were kept up and not allowed to chip/blister exposing bare brick. Then it would make matters worse as moisture would get in and the painted portions would hold in the moisture. Kinda like a poor vinyl decking job…if seams are allowed to open and moisture gets in, it will rot the deck twice as fast as bare plywood would because it traps the moisture under the protected portions, never allowing it to dry out. Yet when done properly it will likely extend the life of the deck 4-5 times.

Not that I’m aware. There were 4 antennae all over the roof, but none on a chimney.

The chimney top had been repaired in 1983 (written in mortar). So that is possible.

This is what I’m thinking. The odd part was the fact that the bricks that were bad were in the middle of the chimney. But I do believe that it is a combination of old brick and water penetration.

Thanks for the input guys. Any other thoughts?


I have seen this on old, very old brick found here. Often these bricks are on chimneys, unfired and handmade on site…they get soft and crumble to nothing…as posted by another I agree moisture can be an accelorator of the problem. I have removed these chimneys below roof level when re-roofing houses and re-laid on top of the old brick that were protected inside of the house which were found to be in satisfactory condition.

Thanks very much. That’s interesting.


Good article David. We actually use the Chimney Saver products regularly and recommend them to most of our customers. -Tom

What was the flue made of? If clay tile, there may have been a breach at one of the joints. This can generate a lot of localized moisture from the inside.

Those were my thoughts when I first saw this. Did the chimney even have the liner in it?

It’s a great site. I included the link on my website. Thanks!

David or Chimney Pro:

Can the Chimney Saver product be used on painted brick. I didn’t see that discussed.

Exterior brick spalling - I have moderate to extensive brick spalling/splitting on the two chimneys in my 20 year old house. The brick has been painted. Repainting to “seal” the brick hasn’t worked at all. The brick spalling flakes up 1/32nd-1/16th inch slabs of painted brick facia.

Some suggestions I’ve read to replace the spalled brick aren’t reasonable due to the amount of brick involved.

Would any of the masonry /brick breathable waterproofers such as Chimney Saver work on this painted brick application? Would their be an industrial resin repair product that might be applied to stabilize the brick?



Once brick is painted, the brick loses it porous effect. Most paints repel liquids, so I would have to say “No”, to applying Chimney Saver to painted brick.

If you were to apply this liquid to the painted brick, it wouldn’t stick to the brick due to the loss of capillary action that an unpainted brick has.

Your best bet is to have the paint removed from the chimney, for two reasons.

  1. Paint is very ugly on chimneys
  2. The existing painted bricks will not hold any sort of waterproofing solution.

Also, if the chimney is painted, you’d think that the paint would prevent rain from getting sucked into the brick and causing damage.

Have you considered rebuilding the chimneys? Sounds like you would be further ahead in doing so.

I believe they have proven water proofing a brick just leads to quicker decay as the bricks no longer breath and dry out .
Trapped water freezes and then the face blows off.
I have info some where will look and post it when I find it .