What exactly is spalling, and how does it impact your chimney? Spalling is the flaking off of a brick surface and is evident when the face of the masonry is missing. Pieces of brick(s) may be found on the ground, in your gutters, or on your roof, all of which is an indication that there is a problem that needs to be addressed. Chimney spalling is a sign of severe moisture penetration of your masonry bricks.
What Causes Chimney Spalling?
Spalling is caused when the masonry absorbs too much moisture and is subjected to freeze/thaw cycles. Damages can be worsened by condensation of flue gases in improperly-sized flue liners and gaps or cracks in mortar joints on the inside of your chimney, as well as by moisture entering the interior of your chimney via a crack in your chimney’s crown.
Softer types of bricks are more susceptible to moisture penetration than hard type bricks. Unfortunately, builders often opt to use softer type bricks because they are the lesser expensive of the available options. If you find yourself having to rebuild your chimney because the brickwork is beyond repair, request that hard bricks be used to ensure that your completed project lasts longer.
Why Is My Chimney Masonry Flaking, But Other Areas of My Home Are Fine?
Chimneys usually show damage more than other parts of your home because they’re more exposed. As you might expect, the top portion of your chimney will show the first signs of moisture intrusion issues. By the time bricks spall, the damage has already been done. These bricks cannot be repaired and, instead, must be replaced.
It may be tempting to cut a few corners in an attempt to save money and replace only a few spalled bricks or only do a partial rebuild of your chimney… Keep in mind, however, that your entire chimney will need to be rebuilt at some point, and, as such, any partial repair will only be a temporary fix. You can put makeup on a pig, but it’s still going to be a pig.
How Can I Prevent Brickwork From Spalling?
Spalling occurs when water penetrates brick or mortar and then freezes and expands, causing the surface to flake, chip, or break apart. Preventing this damage starts with keeping moisture out and maintaining the integrity of the masonry.
Keep Moisture Out
The most effective way to prevent spalling is to control water penetration.
- Seal the brickwork with a high-quality, vapor-permeable waterproofing product that keeps water out while allowing moisture inside the masonry to escape.
- Repair cracks in the crown, mortar joints, or brick surfaces promptly to stop water from seeping in.
- Install or maintain a chimney cap to keep rain and snow from entering through the flue.
Protect Against Freeze/Thaw Damage
Moisture inside masonry is especially damaging in colder climates.
- Ensure the structure can fully dry between wet periods.
- Cap and flash the chimney or wall properly to shed water away from the masonry.
- Address drainage issues at the base of the structure to prevent water from pooling.
Choose Durable Materials
The type of brick and mortar matters for long-term durability.
- Select hard-fired bricks that are less porous and better able to resist moisture.
- Use high-quality mortar that can handle expansion and contraction without cracking.
- When rebuilding or repairing, choose materials designed to withstand local weather conditions.
Stay on Top of Maintenance
Routine upkeep goes a long way in preventing bigger problems.
- Schedule annual inspections to catch early signs of deterioration or water damage.
- Repoint deteriorating mortar joints to restore the protective seal between bricks.
- Clean away moss, efflorescence, or other buildup that can trap moisture against the masonry.
Control Interior Moisture
Moisture can come from inside the chimney or structure as well as outside.
- Make sure the flue is properly sized and lined to reduce condensation of flue gases.
- Burn only dry, seasoned wood in fireplaces or stoves to minimize excess moisture.
- Maintain proper ventilation to help keep masonry dry from the inside out.
By keeping water out, using the right materials, and staying consistent with maintenance, you can greatly reduce the risk of spalling and extend the life of your brickwork.
Reach Out Today
If chimney spalling has become an issue for you, the time for repairs is now! At Ace Chimney Sweeps, we know how important your family’s safety is, and how dedicated you are to protecting your investment. That’s why we make the safety and efficiency of your chimney, fireplace, air duct system and dryer vent system our priority. Let us put our over twenty years of experience to work for you. Give us a call today!