Do you have some old masonry work outside your home? In many places you can find walls and other features that were built a long time ago, adding a lot of character to a home. These features can be very sensitive to changes in weather, especially when they get older. The reason is that there will be cracks formed in the masonry work where water could intrude. When the weather drops below freezing, these cracks will expand and over time, and they will be big enough to pose a serious problem to the integrity of the entire feature.
There are a few steps that you should take to prevent water from damaging these beautiful things. The first is to ensure that there is proper grading around them, funneling water away from them instead of letting it pool up around them. You can also apply a sealant regularly that keeps the water from entering these cracks. Just make sure to regularly reapply it as it wears off.