What Causes Mold in the Chimney & Fireplace?

12/26/2019 (Permalink)

Simply put, mold requires moisture. Every cause of mold in your fireplace or chimney is based on the idea that something is allowing moisture into the area. Here are a few common ways moisture can cause fireplace mold:

Poor Ventilation – Poor ventilation traps condensation in the chimney and creates an environment that promotes mold growth.

Broken Chimney Crown – If the chimney crown or chimney cover is damaged, it can let in enough water to create a moisture-rich environment, allowing mold to thrive. Just one crack is enough to feed a mold growth.

Non-Waterproofed Brick & Mortar – If the brick and mortar of your chimney wasn’t properly waterproofed with sealant, water will seep through.

Chimney Cap Failure – If the chimney cap on your chimney is damaged from rust, severe weather, or improper installation, it won’t be able to properly keep moisture out.

In many cases, damage that leads to mold happens slowly over time. You may never notice it until it’s too late, which is why it’s important to have a professional chimney inspection annually.