Home Chimney Repair Basics

Regardless of its material, a chimney is exposed to various elements that cause yearly damage. Moisture is a common problem when rainwater or melting snow and ice seep into brick or mortar joints. This causes spalling, which makes bricks pop or crumble.

Chimney cracks expose smoke and toxic gasses like carbon monoxide to enter the home, posing major safety hazards. Fortunately, Chimney Repair Charleston SC can fix these issues quickly and easily.


Chimney caps protect the upper opening of your chimney from rainwater, debris, and animals. If your chimney cap is damaged, it may be a sign that it’s time to replace it. It also helps keep sparks and embers inside of your chimney.

Chimney caps should be inspected regularly for signs of damage or wear. First, you’ll want to check whether the cap is securely attached to the chimney. If the screws that attach the cap to the chimney crown come loose, it’s a good idea to have the cap repaired or replaced.

When a chimney cap is loose, it can easily be blown away by winds or fall off completely. If this happens, it will let water, creosote, ash and other contaminants into your home. The next issue to look for is cracks in the cap. Especially in areas that experience freezing and thawing, concrete chimney caps can crack or spall. These cracks are a direct threat to the chimney itself as moisture will penetrate and weaken the masonry structure of the chimney.

It’s a good idea to use a pre-mixed concrete patch or mortar to repair these cracks. When this mixture is injected into the cracks, it will fill in the space and form a protective seal against moisture. If you’re repairing large cracks on the crown, it is a good idea to cover the area with a waterproof crown sealer.

Lastly, you’ll want to inspect the chimney cap for signs of rust and corrosion. Although most are painted with heat-resistant paint to hinder rust, this coating can crack or peel over time. Chimney caps that are heavily rusted should be replaced, preferably with a stainless steel variety.

Chimney cap repairs are best done by a professional chimney sweep. If you’re attempting to do the work yourself, make sure that you have the right equipment for working on a roof, including a metal ridge anchor that secures to the peak of the chimney, a body harness that fits around your back and hips, and a rope with an automatic locking mechanism that stops your fall if you lose control. You can rent these safety items at home improvement centers and tool-rental outlets.

The flue liner is a critical part of your chimney system. It prevents corrosive gases, ash and creosote from affecting the masonry of your chimney. It also serves as an insulation layer and improves the structural integrity of a chimney.

Cracks in a chimney’s flue liner allow heat and flames to penetrate the masonry structure, which can lead to a chimney fire. These fires can quickly spread to nearby combustible materials, including your attic and roof.

If the flue liner is cracked or deteriorating, it’s important to have it repaired by a professional chimney technician. Annual chimney inspections can detect liner damage and determine if it’s time to replace the flue liner.

You can easily check for a cracked or damaged flue tile by climbing to the roof and shining a flashlight down your chimney. Look for the top section of the clay tiles to see if any are crumbling or breaking apart. Typically, these are the first section to fail because they’re subjected to the most extreme temperature changes.

Replacing a damaged clay tile liner is a complex job that requires the services of a certified chimney professional. A chimney expert will use special equipment to pour a concrete-like product along the walls of your chimney’s passageway. This type of cast liner provides a safe, insulated and watertight seal while improving the chimney’s structural integrity. Research shows that this type of chimney liner also helps a fireplace burn more efficiently, reducing the amount of creosote that builds up in the flue.

Chimney leaks caused by a cracked or damaged chimney flue liner can expose your household to carbon monoxide poisoning. This gas is odorless, tasteless and invisible, and it can be fatal. Those who suffer from carbon monoxide poisoning often don’t realize it until it’s too late and they pass away.

While you can patch up small cracks in the clay chimney tile, a new metal chimney liner should be installed if your flue liner is extensively damaged. A new metal chimney liner is made of stainless steel or aluminum. Stainless steel is the preferred chimney liner among fire-protection experts because it will last for the life of your home’s chimney.

The crown is the chimney’s topmost surface that shelters the flue and typically has a screen to keep birds and other critters out. Like the rest of your chimney, it is subjected to a variety of weather elements all year long. The most common damage to the crown comes from water. Rainwater or melting snow and ice seep in between the bricks, and as the water freezes and thaws back and forth, it can weaken and crumble the masonry work. If left untreated, a damaged chimney crown can deteriorate and eventually collapse.

Moisture can also destroy the interior of your chimney by causing the flue liner to crack, rust and corrode. It can also wreak havoc on your chimney structure by making the bricks deteriorate. In addition, it can saturate walls in your home with moisture, leading to mildew and mold and compromising the structural integrity of your home.

Your best bet to avoid the dangers of moisture damage is a routine chimney inspection. A reputable company will examine your chimney’s exterior, fireplace and flue liner for signs of damage.

One of the most common indicators of chimney deterioration is spalling, which happens when the outer layers of brick flake or chip off, exposing the inner, more porous layers. This process can accelerate and exacerbate chimney deterioration, so it is important to have it repaired promptly.

Chimney deterioration can also show up as cracks and gaps in the mortar joints. These are a serious concern, since they increase the amount of water that leaks into the chimney and ruins the structure. To prevent these leaks, a professional can repair your chimney’s mortar joints by cleaning out the cracks and then filling them with high-heat mortar.

While it is possible to do some minor masonry repairs on your own, hiring a professional can save you money in the long run. Make sure that your chimney repair professional has the proper experience, knowledge and tools to safely and effectively complete any necessary repairs. A mason that specializes in chimney repair should be certified by the National Fireplace Institute and should use fall-arresting equipment when working on a steep or high roof.

The flashing is a vital part of the chimney structure that prevents water leaks. It is installed where the chimney meets the roofline, forming a waterproof seal to keep rainwater and melting snow out of the house. The flashing is often made of copper or steel, although lead and even PVC have been used in some cases. It is a very important component, and if it becomes damaged, it needs to be repaired as quickly as possible.

One of the most common reasons that flashing fails is because it gets damaged by weather elements. Moisture, in particular, is a major culprit. Rainwater and melting snow penetrate the bricks, and over time they cause a problem known as spalling. This happens when the moisture freezes and thaws repeatedly, damaging the surface of the brick. Eventually, the brick can crack and crumble. The resulting leaks will not only damage the inside of the chimney, but they can also damage the roof and other parts of the house.

In addition, the flashing can get damaged by missing or badly installed shingles. It is important to have your chimney professionally inspected if you notice any signs of flashing problems.

Flashing is usually installed in two layers, with the base flashing being inserted against the chimney’s masonry and the counter-flashing being tucked under the shingles. If either of these are damaged, it is important to have them repaired as soon as possible to avoid water leaks.

The chimney crown and the flashing are often overlooked because they are out of sight and out of mind. However, these structures are critical to a functioning chimney. If you suspect that your chimney may be in need of repair, contact a reputable home chimney repair service as soon as possible.

When working on a roof, it is very important to use a fall-arrest harness tethered to an anchor point. These harnesses are available at home improvement centers and tool-rental outlets. You should also always work on a clear day with dry weather to minimize the risk of slips and falls.

Patricia Mann