How to take care of your masonry chimney

Let's start with the basics

A chimney is a device that carries the exhaust gases and/or smoke to the exterior. There may be one or more flues in the chimney, it depends on how many fireplaces or gas powered appliances are connected to it.

How a chimney develops problems

A chimney is susceptible to water infiltration if not properly taken care of. Masonry is a porous product by nature and in our climate, water will get in, freeze and damages the materials like spalling or flaking as in the picture to the right. A great way to avoid this is to treat your chimney with a waterproof type of product. There are commercial products available you can buy at your local hardware store like Thompsons Waterseal and so on. Basically, you are displacing the water by using these products. I recommend treating the entire masonry part of the chimney including the flue and cap.

A chimney "flue" is not something you catch  

The flues are the pathways the exhaust gas, or smoke travel through. They can have there own problems if we do the wrong things. For example, we see a lot of flues that are only servicing the water heater because the furnace has been replaced with a high efficiency one that vents out the side of the home. When the furnace and water heater were both using the same flue there was enough force from both appliances to get the gases all the way up and out. Now that the furnace has been changed, the water heater does not have enough force by itself to do this, and we see the flues become damaged due to condensation. If that is the case, we suggest a chimney liner, which reduces the inside diameter of the chimney thus providing a proper pathway. A second choice, would be to replace the water heater with a direct vent or tankless water heater that vents out the side of the house. The chimney can be removed or concreted shut.

"Flashing" it's not what your thinking

Flashing is the material that connects the roof to the chimney. This material can become damage, or may lift up over time. Many times I will find that the metal has been tarred over, which is a common practice. Keeping your flashings in good shape is a vital key to keeping water out of the home.