# White stains on red brick buildings

**URL:** <https://boards.straightdope.com/t/white-stains-on-red-brick-buildings/380389>\
**Category:** Factual Questions\
**Created:** [November 14, 2006, 3:58pm UTC](https://boards.straightdope.com/t/white-stains-on-red-brick-buildings/380389 "2006-11-14T15:58:42Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Pushkin](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@Pushkin](https://boards.straightdope.com/u/Pushkin)\
**Post date:** [November 14, 2006, 3:58pm UTC](https://boards.straightdope.com/t/white-stains-on-red-brick-buildings/380389/1 "2006-11-14T15:58:42Z")

</div>

A few weeks after a red brick build goes up, the bricks are stained white. Is this something leaching out from the bricks themselves or the cement between them?

---

<div class="post-metadata">

**Author:** ![MikeG](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikeg/32/4329_2.png) [@MikeG](https://boards.straightdope.com/u/MikeG)\
**Post date:** [November 14, 2006, 4:06pm UTC](https://boards.straightdope.com/t/white-stains-on-red-brick-buildings/380389/2 "2006-11-14T16:06:11Z")

</div>

It’s brick [efflorescence](http://www.askthebuilder.com/033_Efflorescence_-_Solving_The_Problem.shtml).

---

<div class="post-metadata">

**Author:** ![FatBaldGuy](https://avatars.discourse-cdn.com/v4/letter/f/ecd19e/32.png) [@FatBaldGuy](https://boards.straightdope.com/u/FatBaldGuy)\
**Post date:** [November 14, 2006, 4:10pm UTC](https://boards.straightdope.com/t/white-stains-on-red-brick-buildings/380389/3 "2006-11-14T16:10:11Z")

</div>

[QUOTE=MikeG]  
It’s brick [efflorescence](http://www.askthebuilder.com/033_Efflorescence_-_Solving_The_Problem.shtml).  
[/QUOTE]

And here I was, all ready to blame the pigeons.