white powder from brick fireplace
 

We have a brick storage space for firewood next to our brick fireplace and chimney in our den. There seems to be a white powder flaking off along with chips of mortar falling from the storage space onto the hearth. Can this deterioration be stopped? It seems more frequent when it rains. Can it be coated to prevent the erosion? Can water be entering from the outside and causing this? Is this called leaching?

Take some pictures of it and e-mail them to your local major bricklaying contractors to confirm. It's probably something called "effluorescence".

It's due to water getting into the masonary somewhere, probably on the outside. As the water migrates through the masonary, it picks up water soluble clays and salts along it's way. When the water gets to the surface of the masonary, the water evaporates, leaving the white salts and clays behind as a precipitate.


Bingo.

If you see any "flaking" of the surface of the mortar or brick, that's due to the wet masonary freezing. As the water in the masonary freezes, it expands and the expansion breaks the masonary where it's least able to resist that expansion, which is the masonary breaking off in flakes near the surface.

Thanks for the reply. You apparently know about this problem. That sounds like what is happening with water entering the bricks. The house is 25 years old so I think it needs some repair of the bricks and mortar.