Sealing your chimney and walls from the elements

If you have a masonry chimney or walls made with mortar and materials such as brick, stone, or cement, Your chimney was designed to absorb water. That is not a good thing, but it is a fact. Water repellent sealants can help greatly.

The Enemy Inside

 Masonry chimneys are more susceptible to moisture. The mortar and bricks, stone, or cement are porous, somewhat like a sponge. Porous materials have a higher capillary action, meaning they can absorb moisture without the aid of external forces such as gravity. The action is also known as “wicking.” When a masonry chimney has wicked moisture, winter weather and rainy seasons like we have in Cincinnati becomes an issue. 

Moisture inside can do extensive damage to your chimney during the freeze-thaw cycle and can loosen the mortar around the bricks, stones, or cement blocks and cause your chimney to crumble and collapse. Once the mortar opens cracks for the water to seep in, it creates even more opportunity for moisture to get in. If it gets behind the brick, the face of the brick will pop off, this is known as spalling. You can see how moisture can be a significant problem for masonry chimneys; that is where a chimney sealant becomes a solution.

What is a Water-Resistant Sealant?

A water-resistant sealant is a coating designed to keep moisture out while being vapor permeable, meaning it won’t trap moisture inside your chimney. A chimney sealant is made primarily from polyurethane or silicone and can be sprayed, brushed, or troweled. It is best to let a qualified chimney sweep apply a chimney sealant rather than attempt to do it yourself. A chimney sweep will know how many coats to apply to the chimney and what type of chimney sealant will work best.

Is My Masonry Chimney Moisture Damaged?

If you have been considering using a water repellant sealant, you probably already suspect your masonry chimney already has some degree of moisture damage, but you need to be sure. Here are a few common signs of moisture damage from the team at Best Cincinnati Chimney.

• White powdery deposits on the exterior of your chimney.
• Hairline or larger cracks.
• Bricks, stone, or cement that has chips or flakes coming loose.
• Eroded or absent mortar joints.
• Loose or missing bricks, stones, or blocks.

If you have noticed one or more of the last three problems on your chimney, it may be too late for a sealant to work and may need to be repaired by a qualified chimney sweep.

Is a Water Repellant Sealant needed on a new chimney?

A chimney sealant on a new masonry chimney is an excellent way to perform preventative maintenance. A chimney sealant can protect a chimney anywhere from five to fifteen years which extends the life of your chimney by the same amount of time. Apply coats of chimney sealer about every five years will keep your chimney in good shape.

Suppose your chimney is just starting to show signs of moisture damage; it’s probably not too late for a chimney sealant to be effective. Hairline cracks and slightly eroded mortar can still be coated with a sealer to slow or stop the progression of the damage. However, if your chimney has bricks, stones or blocks missing and the mortar is nearly gone, it is more likely that your chimney will need to be repaired. As we stated earlier, if your chimney is starting to crumble, then it’s a matter of when it will collapse, not if it will collapse. Once a masonry chimney has been repaired or replaced, it can then be sealed with a water repellent to keep those repairs for years to come.

Get A Chimney Inspection

To really know if your chimney should be sealed or repaired, an examination by a certified chimney inspector will be required. A chimney inspector can detect problems with your chimney the untrained eye will miss.

When it comes to the safety of your home and the well-being of your chimney, an inspection should be done annually. There are other issues in addition to moisture damage that may need to be addressed.

Best Cincinnati Chimney to the Rescue

If you think your masonry chimney has moisture damage, or you just want to seal your chimney for its long-term benefit, Best Cincinnati Chimney can help. Call us today or fill out our contact form, and one of our knowledgeable and friendly staff will reach out to you. We can schedule a time convenient for you to have your chimney inspected. At the time of the inspection, we can seal your chimney to help preserve it for the life of your home.