The main purpose of a chimney is to safely exhaust products of combustion out of your home.

Weak Draft

In addition to safely exhausting products of combustion from your home, chimneys often also draw oxygen into the appliance they vent in order to allow for the combustion needed to light/run the appliance. Interferences with either of these 2 functions will affect the overall operation and efficiency of the unit. It may cause issues such as the room becoming smokey when you have a fire lit, or your furnace may not work as well as it did or at all.

Draft is the force or pressure difference between the inside and outside of the venting system which makes gases created by the unit draw up and out of the chimney.
Flow is the volume of those gases that pass through the system as the result of the draft.

All chimneys rely on draft and flow. The temperature difference between the inside and outside air, as well as the overall width and height of the flue, will affect the draft. These elements need to balance out in order to have a properly operating flue system. Sometimes trouble with keeping a fire lit or smoke filling the room can mean that the flue size is too large/small (depending on your heating system), or that your chimney needs to be extended. 

Sometimes draft issues are simply caused by debris build up in the flue.

Blocked Chimney

Your fireplace, wood stove, insert, furnace chimney, and even clothes dryer vent may at some point become blocked by organic debris or parts of the chimney itself, often masonry debris. Most debris affecting the performance of your chimney and connected appliances can be removed during the sweep process. In many cases, this can solve the issue of "weak draft".

When debris is the result of deterioration of the chimney lining (flue) or the exterior structure of the chimney (chase), repairs will be recommended. In some cases we will recommend that you do not use an appliance venting through the affected chimney until it is repaired. Many times the simplest way to delay deterioration of your chimney's flue is to install a chimney cap.

Flue: The flue is the inner chamber of your chimney which carries the combustion gases from your home.
Chase: The exterior structure of your chimney which serves to insulate the flue.

Call or email us with questions or to schedule your Chimney Inspection.


While caps prevent water from entering the top of the chimney, there are plenty of other conditions that can allow water in, damaging the chimney structure and spreading to the ceiling walls and floor around it.

indicators of leaks

  • Staining on the ceiling above your fireplace
  • Deteriorated mortar joints or cracked bricks in the firebox
  • Rust on steel or cast iron parts, such as the fireplace grate or damper
  • Rusting or stained pipes where they enter the wall

Common Causes of leaks

Damaged Mortar Joints
Changing temperatures cause the mortar joints of the chase to expand and contract so that over time the joints wear down and allow water into the sides of the chimney. To repair the joints some of the old mortar is removed and replaced with new mortar matching the existing.

Damaged Bricks
If there are cracked or damaged bricks, these are removed and replaced with new bricks matching the existing ones as closely as possible.

Cracked or Missing Crown
A cracked or missing crown or damaged chase cover allows water into the chimney, damaging all of the lower components of the system.

Gaps in flashing
Damaged or improperly installed flashing not only causes deterioration of the chimney striation, it also allows a path for water to penetrate and damage the roof structure.

Crown: The chimney crown (or chimney wash, crown wash) is the top of a masonry chimney. It covers and seals the top of the chimney from the outside edge of the flue liner to the chimney edge. The crown should have a downward slope that will shed water from the flue to the edge of the crown and away from the chimney.
Chase Cover: A chase cover is a metal cover that fits over your chimney chase serving the same purpose as a crown. It should prevent water from entering the chimney. Chase covers are usually found on chimneys with wood, metal, or vinyl siding but can also be used on masonry chimneys. Often chase covers are made of galvanized steel and will rust over time. These are usually replaced with stainless steel chase covers.

No Chimney Cap

Your chimney needs a cap. Chimney caps keep rain, animals, branches, and other debris from entering your chimney. Chimney caps prevent embers or sparks from floating up and exiting the chimney, potentially starting a fire on your roof or neighboring structures. They also help prevent downdrafts which can blow smoke into your home while a fire is lit. If you’ve noticed strange odors or sounds coming from your chimney, you might have an animal living inside of the chimney which means it’s time to get it a cap!

Chimney caps (also known as spark arrestors) come in many shapes, sizes, and materials. The most common caps are square or round, often stainless steel fixtures with flat tops and stainless steel grate all around the sides. They are usually attached to the very top of the chimney flue. 

Sometimes your chimney may have multiple flues that operate just fine very close together. In these cases, a custom multi flue cap can be attached to the chase rather than the individual flues.

Call or email us with questions or to schedule your Chimney Inspection.