Chimney Mortar Repair- The When, What and How

When?
Naturally the first response to this question is simply put, whenever you are on your roof or prior to having a fire in the fireplace. The rule of thumb is to do a thorough inspection of all mortar on your chimney at least once a year or after a major event such as an earthquake or hurricane. Most individuals decide to do this whenever they are sweeping the leaves off of the roof, inspecting their shingles or simply cleaning the gutters. The more you inspect your chimney the better. You might be able to notice a needed repair before it becomes a big problem so inspect as often as you can.

What?
When your doing your inside and outside inspections, look for any cracks in the mortar (the grayish colored joints between the brick). Some of these cracks might be easily found while others are simply a hairline crack that isn’t so easy to see. Also inspect the bricks themselves. You will want to take note of any loose bricks and be sure to either have a profession mason do the repair or make sure to place enough of the repair mortar between those bricks to secure them firmly.

How?
Clean the repair area thoroughly. Start from the bottom of the repair and work your way up. Use hand tools such as a wire brush, a chisel and hammer and possibly even a grinder with a tuck-pointing attachment to get the corners if necessary.

Buy enough ready-mix mortar for the needed repair. Even if you think you’re buying too much mortar, it’s better to have more than not enough. Mix the mortar according to the instructions on the package and a 5-gallon bucket works great for these types of repairs.

Place the mixed mortar on a mason’s board or similar flat board and place it at the bottom of the repair area. Scope a small portion of mortar onto a trowel and push it into the cracks. When the crack is completely packed full of mortar, place your trowel flat against the bricks and slice with a downward motion so the mortar is flat with the bricks.

Once you are confident that the crack is packed and you took away the excess mortar, compress the mortar and use a jointing tool to make a “V” in the mortar. This can also be done with the point of your trowel. Once the mortar is dry, you can use a wire brush to clean the face of the bricks.