Dan from Fort Erie, Ontario wrote: I purchased a retirement home here just over an year ago and have noticed that the angel stone facing on the front of the house is breaking off. The house is about 40 years old and I suspect the angel stone is original. It appears that water is getting into cracks in the face of the stone and freezing during winter and pushing the faces off the bricks. The bricks themselves appear well attached to the house but something is causing the faces (about 1/2 inch deep) to break away. I have read on your site about not trying to seal old bricks, and I suspect the angel stone would be the same. Is there a way to prevent further breaking, and, is it possible to somehow re-attach pieces of stone that have fallen off?
If the pieces of stone are large enough you can glue them back on. The best adhesive for stone and masonry is PL Premium, but be careful, it will stain the surface, and will make a dark brown line at the glue joint if you let the glue go to the edge. Colour matched caulking is not good for this because it is so flexible that the stone will creep.
The real problem, as you suspect, is moisture getting into the stone and then freezing. If there are serious cracks in the outer face of the stone, there may not be much to save you, although much less water actually goes in through rain hitting the face, than through cracks around windows or other flashing problems. Most common problems are either below window sills that leak badly into the wall, or areas where there is a lot of humidity inside the house at that point, and the wall is not sealed on the inside. Tremendous amounts of moisture can move through an electrical outlet, or around unseal window frames from the inside of the house and right into the brick. This is most often the cause of such cracking and spalling. Either reduce the humidity inside (add bathroom fans for instance) or make the electrical boxes and other holes in the wall air tight, or better yet do both.