It's rainy today, photograph your masonry walls

Masonry walls are amazingly resistant to the ravages of time. They do not fade, rust, rot or burn. Brick walls never need repainting, although concrete block ones
need to have the water repellent coating renewed from time to time. The number one enemy of masonry in Colorado is water, coupled with our climate where the temperature often drops below freezing. When water freezes, it expands 9%. This expansion can crack even the sturdiest construction. We have over 150 freeze-thaw cycles a year in Denver. If a brick is saturated when the temperature dips below 32 degrees, this expansion causes hairline cracks that can lead to more significant problems down the road. My best advice is to keep your masonry dry. Make sure the gutters and downspouts are repaired so they can quickly flush water away from the wall. Verify that the parapet caps and the window sills are firm and tight and shed water well. The National Trust for Historic Preservation suggests that you take photographs of your building once a year--about 2 to 4 hours after a rain storm.
These annual photographs will let you compare the condition of the building from year to year. If you see any puddles at the base of the building it means that you should re-grade your landscaping or re-slope the sidewalk. If you see big wet patches on the wall, this indicates that water is getting into the wall instead of being shed away. This greatly increases the likelihood that your wall will be wet one night when it freezes. You are likely to see these wet spots under window sills, under parapet caps and behind downspouts. If you suspect that the joints in a particular area of the wall are damaged, take a key and run it along a horizontal mortar joint, pressing firmly. If little flakes of white mortar pop off the wall, your mortar joints probably need repointing. You do not have to repoint the entire wall—just the damaged portion.