Materials used to construct a masonry chimney are usually porous and can absorb large amounts of moisture. Waterproofing materials are available which allow the chimney to breathe and yet prevent water from entering from the outside. Applying waterproofing should only be done to a unit that is sound; any repairs that are needed should be made before applying the waterproofing agents. If needed, the chimney’s exterior should also be cleaned prior to application.
A chimney cap can keep weather and animals out of your chimney all year round.
Install a Chimney Cap
The most inexpensive and common sense approach to moisture prevention in a chimney is the installation of a chimney cap. It only makes sense to install a chimney cap, since large amounts of water can enter the chimney without one.