Water and Your Masonry Chimney
Your chimney is a hard worker. As part of your homes heating system the chimneys job is to safely vent fumes and smoke up and out of your home. Many homeowners love the charm of a fireplace or woodstove. Others love the benefits of the lower heating costs that are associated with the use of their fireplaces and woodstoves. And, finally, some people do not give any thought to their masonry chimney because they do not have a fireplace or hearth stove. Whichever bracket you may fall into there are some important things that you should know about your chimney that could protect your family, and the investment that you have made in the purchase of your home.
As an integral part of your homes heating system your chimney needs to be maintained to keep the system running safely and efficiently.
Unlike most of the masonry that may be a part of your particular homes construction, masonry chimneys extend above the roofline and therefore they are continually exposed to the sun, wind, rain, and snow. The combination of this constant exposure to the elements along with constant internal temperature changes often causes masonry chimneys to deteriorate. This is especially true when maintenance and/or small repairs aren’t made in a timely fashion.
Masonry chimneys that are not protected and waterproofed properly will absorb and retain water. This water will cause damage when it freezes, and/or when it mixes with soot or creosote within the flue. If a chimney is not regularly maintained, a small job can turn into a costly major repair.
What is considered a Masonry Chimney?
A masonry chimney is one that is constructed with materials such as:
- concrete or concrete blocks
- flue tiles
- stainless steel flue lining
- some masonry chimneys may have a steel fireplace and damper system
Effects of Water & Your Leaking Chimney
Other than stone all of the above masonry construction materials can deteriorate as a result of prolonged contact with water. In areas where a chimney is exposed to freezing temperatures and where moisture has penetrated the masonry when it freezes and thaws, the expansion can cause stress. Stone chimneys may be immune to water but the mortar that bonds the chimney may not. Water can also cause rust in steel or cast iron that weakens metal parts. Also, when water mixes with creosote or soot within in a chimney that is serving a wood stove or oil fired heater, it can produce acid that will deteriorate the chimney from within. Another potential byproduct of this water and soot mixture is an unpleasant odor in your house. Homeowners in the Philadelphia and surrounding PA areas live in a climate that is particularly hard on masonry chimneys.
Interior or exterior damage to your chimney could include:
- Rusted fireplace accessories or metal parts on glass doors
- A deteriorated metal or masonry firebox
- A rusted damper assembly
- Rotted adjacent wood or ruined wall coverings
- Water stained or damaged walls, floor or ceiling
- A deteriorated central heating system
- A cracked flue lining system
- Stained chimney on the exterior
- Decayed exterior mortar joints
- A collapsed hearth support
- Collapsed or uneven chimney structure
- Chimney settlement
Preventing Water Damage with Chimney Caps
Chimney caps or rain covers are one of the most inexpensive ways a homeowner can prevent water damage to their chimney. Chimney caps are a preventative measure that the Underwriters Laboratories (UL) specifies “standard” to any chimney that is considered safe and well-maintained.
A chimney may have one or more large openings (called a flue) at the top that collects rainwater and funnels it directly to the chimney’s interior. This opening has the potential to allow a substantial amount of rain or snow into your chimney during the winter (when freeze / thaw cycles occur most).
Chimney Caps – why you need one
A chimney cap has benefits other than preventing water damage. A cap can also prevent birds or other animals from entering into or nesting in your chimney. Moreover, they can function as spark arrestors, preventing any sparks from landing on your roof or other homes or objects that could be combustible.