Q: My mother's house, built around 1920, has a brick foundation. These bricks are continuously flaking off on the inside. The flaking occurs on the mortar as well as on the bricks themselves. I suppose this is due to moisture, but I am not sure. Do you know if there is anything we can do about this?
A: The flaking of old bricks, a condition known as sprawling, is not unusual. It is not something to worry about as long as it is only slight surface flaking. However, this would not account for the condition you describe with the mortar, which should not flake or crumble. The brickwork probably needs to be repaired by tuck pointing or re-pointing -- both inside and outside. This involves scraping out the old mortar to a depth of at least one-half inch, then re-pointing the joint with new mortar cement. If there is a moisture problem, this may help, but it depends on how severe the problem is.
Q: Due to the fact that the bricks in our chimney had been flaking, we recently had many of them replaced with new ones. Now the new ones are covered with a white powdery substance. Can you tell me how to correct this, and whether I should spray the rest of the old bricks with silicone to prevent further flaking?
A: The white powder is probably efflorescene -- not uncommon on new or freshly laid bricks. It is caused by the leaching out of alkaline salts in the masonry. Washing with a dilute solution of muriatic acid will get rid of it, but it may come back again. Spraying the old bricks with silicone will not help much, so I don't recommend it.