Here are a few facts about masonry crack repair that you may not be aware of:
- Cracks need to be repaired.
- It matters if the cracks are dormant or active.
- The cause of the cracks is important to determine.
- Repointing may not be a lasting solution.
You will not likely be able to meet all the above criteria when attempting to repair cracks yourself. Calling in a professional will save you time and money. No two cracks are the same. The General Services Administration provides some useful information here: http://www.gsa.gov/portal/content/111626.
Some cracks let water into your masonry while others admit debris, insects, and contaminants that contribute to mold. All of those cracks need to be repaired. Cracks that are doing none of those things aren’t really a problem, but are cosmetic issues. That might be important if you are trying to sell your home, as the cracks could be a warning sign to the new buyer.
Whether cracks are old and “stable” or new and “developing” is extremely important to figure out what is causing them. If they are dormant, different materials may be used in repairs than if they are active. Determining the dormancy of a crack can also impact how time-sensitive the repair will be. Some cracks need an urgent response.
Both the method and the materials used to repair cracks in masonry depend on what caused them. Damage caused by a crawling vine is not approached the same way as an improperly constructed chimney crown, even if water penetration results from both. Determining the cause of cracks in masonry is so important that special monitors exist to facilitate it.
Repointing may be a solution, but there may be additional changes needed to keep the water out. Mortar replacement alone will likely be a temporary fix. These decisions are complicated and you should consult a certified chimney sweep to help you protect your fireplace system from moisture and other contaminants.