Spring showers bring summer flowers. Unfortunately, heavy rains can also lead to leaky chimneys.
How do you know if your chimney is leaking? Here’s what to look for, reasons why chimneys leak, how to fix the leaks, and how to prevent leaks in the first place.
Many homeowners falsely assume that all leaky chimneys present themselves as visible water in the fireplace or flue. There are other clues, and unfortunately, chimney leaks are often not recognized until they’ve already caused significant damage.
Here are some of the signs that may indicate your chimney is leaking:
Although chimneys look like a simple brick column, they are actually complex structures with a number of different pieces and parts that can fail. Water is its biggest enemy of all of them with the combination of water and a freeze/thaw cycle being a double whammy.
Without a properly fitted chimney cap to protect the top of your flue from water entry, the flue and fireplace are left completely exposed to rain. If your liner is metal, this is often a source of water problems.
Flashing refers to the water tight metal strips that seal the seam between your roof and the bricks.
Chimneys need to be repointed periodically. Repointing is the process of renewing the pointing, the external part of mortar joints. Over time, weathering and decay cause voids in the joints between the bricks, allowing the undesirable entrance of water. There is no other solution than to repoint!
In combination with repointing, waterproofing the masonry helps preventing leaks and water damage.
The waterproofing process involves the application of a specially designed sealant that keeps water out while allowing the masonry to retain its semi- porous nature. These products can even be applied to chimneys with existing water damage as a way to keep it from getting worse. Just be sure to use the right sealer; using silicone based water sealants may trap water and cause more damage than you started with.
The right one to use: polysiloxane type waterproofing agents.
In our area of New England, this flashing is typically copper, with details as shown below. The counter flashing is embedded 1" into the mortar joing, with head flashing at the leading edge of the chimney and apron flashing at the foot.
Copper, metal and flagstone are all good choices.
There are off the shelf and custom versions in copper.
The best way to prevent chimney leaks is by having regular preventative maintenance done on your fireplace and chimney.
There are two steps to this:
1. Have your chimney looked at it annually. This will allow any new chimney or masonry damage to be spotted early on, so that you can have it repaired before it leads to a more serious chimney leak.
2. Plan to repoint and reseal periodically. Include $ in your maintenance budget so that you can repoint and reseal periodically to avoid more costly repairs and consequential damage.