What is this?

[Richard D. Slocum]

Can anyone tell me what or what may have caused these spots on the brick on this home? It appears to be only on the darker brick, that also looks like it may have some sort of glaze on it.(the lighter red brick doesn't have a glazed look to it) House was built in 1954. The spots seem to be located or coming from in small holes in the brick. It is extremely hard stuff, couldn't scrape it off with a knife blade! It appears to have been there for many years. Some areas have turned black. I told the woman I thought that it was probably something from when the brick was fired. Just a guess. There doesn't appear to be anything structurally wrong with the brick itself. She was curious and now so am I. Any ideas?

[Ted Allen]

Originally Posted by rslocum

Can anyone tell me what or what may have caused these spots on the brick on this home? It appears to be only on the darker brick, that also looks like it may have some sort of glaze on it.(the lighter red brick doesn't have a glazed look to it) House was built in 1954. The spots seem to be located or coming from in small holes in the brick. It is extremely hard stuff, couldn't scrape it off with a knife blade! It appears to have been there for many years. Some areas have turned black. I told the woman I thought that it was probably something from when the brick was fired. Just a guess. There doesn't appear to be anything structurally wrong with the brick itself. She was curious and now so am I. Any ideas?

The bricks look to be normal, I have no idea what you might call the little pours seaping minerals, but I think it is fine and Dandy. Then again you might get a brick person to tell you differently, but I doubt it.

[Barry Adair]

Richard,

They look OK from here
You may want to contact or pass this on to your client BIA for further info

[relliott]

imperfections during the original firing.
1) paint it
2) replace it
3) cover it
4) leave it alone
I vote four

[Doug Edwards, CMI]

Typical impurities found in brick. It accounts for the many colors and speckles seen from the firing process and oxidation that takes place afterwards.

Once had a client insist the workmen were smashing their cigarettes out on her new bricks. She was a "head" doctor and was about as anal as anyone Ive ever met. Took a lot of convincing her to accept this was normal appearance for bricks.

Check out this website;

http://www.claybrick.org.za/publicat...ical_Guide.pdf

http://www.bia.org/html/frmset_thnt.htm

[Marcel R. Cyr]

Hi. Richard;

The brick pictures you posted to me are only showing impurities that were in the clay used to manufacture this brick. Some of those impurities will absorb more heat than the clay and produce this affect when firing.

Below is a little more information that might help some understand the process.


PROPERTIES

"All properties of brick are affected by composition of the raw
materials and the manufacturing processes. It is for this reason that
most manufacturers blend clays to reduce the possibility of impurities
from one clay source affecting the overall quality of the finished
product. Similarly, the standardization of the manufacturing processes
permits the manufacturer to limit variations due to processing and to
produce a more uniform product.

Product Use

The properties that most concern the users of brick are 1) durability,
2) color, 3) texture, 4) size variation, 5) compressive strength and
6) absorption."

http://www.bia.org/BIA/technotes/t9.htm


"Common clay is clay or a claylike material that is easily molded or
shaped and changed into a glasslike material at temperatures of 1,100
°C (about 2000 °F) or less. The minerals found in common clay are
biotite, illite, muscovite, and sericite; other minerals, such as
kaolinite, smectite-group clays (montmorillonite, saponite,
nontronite, and so forth), mixed-layer clays, and chlorite, also are
present in many deposits. Common clay is usually higher in alkalies,
alkaline earths, and iron-rich minerals and lower in aluminum than
ball clay, fire clay, and kaolin. Common clay is mined in hundreds of
places across the United States. When common clay is processed, it is
used mainly in the manufacture of building bricks."

Brick Clay: suitable clay for the manufacturing of bricks or coarse
pottery. Often an impure clay containing iron, calcium, magnesium and
other ingredients is referred to as brick clay. The chief chemical
composition of brick clays is silica, alumina, iron oxide, magnesia,
lime and alkalis. Either more or less than the required amount of any
of these constituents may cause serious damage to the products. The
presence of some harmful constituents like iron concretions, stone
particles, soluble salts and limestone has a detrimental effect on
brick."
http://banglapedia.search.com.bd/HT/B_0626.htm


"All properties of brick are affected by composition of the raw
materials and the manufacturing processes. It is for this reason that
most manufacturers blend clays to reduce the possibility of impurities
from one clay source affecting the overall quality of the finished
product. Similarly, the standardization of the manufacturing processes
permits the manufacturer to limit variations due to processing and to
produce a more uniform product.

http://www.mii.org/Minerals/photoclay.html

http://www.state.ar.us/agc/clay.htm

Marcel

[msylvester]

Was there any evidence of vine growth. Just going out on a limb.

[Richard D. Slocum]

Guys, thanks for all of your responses! That is pretty much what I told her(that it was most likely something that occured in the firing process). I will pass along the info you have all sent. It's nice to know I can always count on my NACHI brothers to come through with great information. Thanks again, Rick

Mark, no there was no evidence of any vine or foliage on the home.

[Barry Adair]

Originally Posted by msylvester

Was there any evidence of vine growth. Just going out on a limb.

Not a bad limb to go out on. I've seen what you were referring towards many times. Good call!

[msylvester]

Thanks Bary!

Looks like vine damage to me.