Chimney Masonry Maintenance Guide

A chimney is a wonderful feature of a home. And a well-constructed chimney provides warmth and beauty, increasing the overall value of the property.

It becomes a place that loved ones can gather and peaceful serenity can be achieved.

However, it can also be a headache.

Awful smells, property damaging water, and shelter seeking critters are all examples of the headaches a chimney can create in someone’s home.

For masonry chimney systems and systems with masonry veneers, the elements are able to degrade due to exposure of wind, sun, and rain. Even without a catastrophic event like a tornado or a fallen tree, these factors can cause mortar, stone, and brick to breakdown over time.

Maintaining these systems can allow the homeowner to continue to enjoy their fireplaces without the stress of risking property damage due to negligence.

Where do I start?

One of the best places to get started is an inspection of the masonry system. Though this article applies specifically to chimneys, foundations, walls, and steps can also benefit from an annual inspection. If the system is out of reach, binoculars are a great option that can reveal a great deal. Another option is an annual chimney sweeping, where a professional with the proper equipment can inspect the chimney and the flashing around it for possible signs of weakness.

What am I looking for?

Around the system, you are going to want to find areas of the masonry that have shown signs of corruption. Some of those signs include:

1. Cracked Mortar Joints: When the mortar is exposed to water and there is an expansion and contraction due to freezing and thawing, the mortar within the joint may be forced apart. Once the joint has been opened up, there is more opportunity for water to enter the system and continue the process.
2. Spalled Brick: When water becomes absorbed into the brick and a freeze/ thaw cycle occurs, the face of the brick can pop off.  This occurrence is due to the difference between the hardness of the exterior of the brick and the interior of the brick.  This will cause separation between the harder brick which will push the face forward.
3. Efflorescence:  This process is the movement of the salts with the ceramic porous materials of the bricks, stone or cinder block. This produces a white powder-like substance that becomes incredibly pronounced on the brick. This white substance is an indication that water is being held in the system.
4. Vegetation:  When plants or moss are allowed to take root with a system it indicates a few different problems. The first is the presence of water. The photosynthesis process of a plant cannot occur without water. The second problem is a hole large enough to allow a root system to anchor. These root systems can open up cracks in the masonry which will lead to additional problems.

These signs are indicators that the masonry system that is being observed is most likely compromised in some way and that maintenance is essential. Simple maintenance can reduce the need for costly repairs in the future.

The repointing of a simple mortar joint can prevent the need to replace bricks in the future.

In the case of a chimney, routine maintenance can protect the exterior and interior of the home as well. However, all masonry systems benefit from the following maintenance projects:

• Repointing: Repointing is the replacement of the mortar within the mortar joints. Typically, the corrupted mortar should be removed from the joint and the joint should be cleaned. Once this occurs, the mortar should be replaced.
• Brick Replacement: Brick replacement is the process of replacing brick that has spalled or completely broken. The brick must be completely removed from the system with the surrounding mortar. Then a new bed of mortar needs to be applied and a matching brick inserted into the system.
•  Pressure Washing: Pressure washing is one way to remove the efflorescence, moss, mildew, and dirt away from the masonry.
• Waterproofing/Sealing: Once the integrity of the masonry system has been restored, the masonry can be preserved with a sealant. Different types of systems use different types of products for this process. However, it is very important to ensure the integrity of the mortar and brick faces before applying a sealant.

What if I have a structural issue?

Maintenance of systems that are failing structurally may be a situation where money and resources are being used for a short term fix that will not solve the long term problem.

Examples of structural issues include chimneys that are leaning or have shifted, steps that have major cracks and bowing, or retaining walls that are buckling. It is very important to contact a professional that is capable of the repairs to avoid making the problem worse.

These types of problems are past the point of simple maintenance. They may even warrant the services of a structural engineer to ensure that a permanent solution can be achieved.