Everything You Need to Know About Spalling

Water penetrationAll About Spalling Image - Boston MA - Billy Sweet Chimney can cause some serious issues with your masonry and the working parts of your chimney. Among other things water in your chimney can cause flaking and crumbling of bricks and mortar called spalling. Spalling can lead to a host of problems and should be recognized and repaired before more damage occurs.

Signs of Spalling

The most obvious and common sign of spalling is flaking and crumbling bricks. It can be as minor as flakes of brick falling onto the roof, and as serious as whole bricks falling onto the ground from the top of the chimney. This is an obvious insurance risk aside from the chimney’s use and efficiency because the bricks can cause injury if they fall onto someone. You can sometimes tell there is a problem by cracking, discoloration, or chipping of the mortar between the bricks, but the easiest way to catch water penetration before it becomes a problem is to follow-through with regular preventative maintenance for your chimney system.

Chimney Sweeps and Inspections

The National Fire Protection Association (NFPA) and the Chimney Safety Institute of America (CSIA) recommend annual inspections of the chimney system as well as regular chimney sweeps to keep your chimney clean. Only a CSIA Certified Chimney Sweep® (CCS) has the experience and expertise to notice the problems before they become a problem. By the time the average homeowner notices signs of a leaky chimney, there is extensive unseen damage. The easiest way to avoid the extra cost and headache is to remember these appointments.


When brick and mortar becomes damaged and crumbly and an expert catches the problem, he can remove the mortar and replace it with new mortar of equal strength and color-matched to the existing masonry. Only a professional with experience and training can properly match new and old mortar correctly. If they are matched improperly the integrity of the masonry is compromised and the repair will not last. You can count on Black Moose Chimney and Stove to get it done right the first time. This is a structural repair as much as cosmetic, and your money will bring you back to the safe, efficient, and beautiful chimney of your dreams.


The easiest way to preserve your dream chimney and to prevent water damage like spalling is to waterproof your chimney. This means installing, repairing, or replacing chimney caps, chimney crowns, and flashing. These three things are not optional. They are designed to keep water out of your chimney, and will only work when installed and maintained properly. This saves the homeowner money, while preventing water damage.

There are also methods of waterproofing the actual masonry. Our sweeps can apply an industrial strength waterproofing sealant that prevents water from entering the masonry. This specially formulated sealant actually allows vapors to escape through the masonry, while keeping moisture particles out as well.

To avoid the headache of water damage, spalling, and extensive repairs, call the professionals today. Call Billy Sweet Chimney Sweep today.

The Appalling Truth about Spalling

Did you know your chimney could sweat? Did you know that this process is actually very harmful to your chimney? Well now that it has been brought up, you must learn all the facts. When the bricks of your chimney sweat, spalling can start to occur. If you feel like this could be happening with your chimney, call the professionals at Billy Sweet Chimney Sweep.

What is chimney spalling and how is it caused?


Spalling is what happens when the bricks or stones on your masonry chimney start to come off in flakes or start to go missing because of water penetration. One of the first signs is when you find random bricks on the ground or on your roof. Often times the main cause of spalling is when the water absorbed in the bricks from precipitation freezes and thaws. This can be worsened by the condensation of flue gases in liners that are not the right size, or gaps and cracks in the interior mortar joints. Also, spalling is made more prominent when extra water enters the interior by way of the chimney chase. Softer types of bricks are more likely to have moisture penetration, but are often used over harder types of bricks because they are more cost-friendly.

The chimney will be one of the first places that will show that it has damage since it is constantly exposed to the elements. The spalling will start with the top portions but once one part of the chimney starts to spall the whole inside has already been damaged. These bricks must be replaced since they are permanently damaged.

How can you prevent spalling?

There is no complete way to protect your chimney from water damage, but there are a few things that you can do to help. First, you need to have your chimney waterproofed. Your chimney technician can do that on any dry day after they sweep. The layer of sealant will need about six hours to dry so it is important to plan ahead. If you live somewhere where it rains often, you might look into having a second coat applied. Chimney caps are also another great way to help keep water out, as well as animals and leaves, but must be properly installed to be safe.