Carbon Monoxide Detector– Houses with a furnace, water heater, gas / pellet / wood stove should have one! Symptoms: headaches, nausea and general fatigue are often mistaken for the flu. A tasteless, odorless gas that can be fatal to your family.

Chimney – Container that holds your flues and damper. Can be masonry or have the appearance of your home. A chimney that has the appearance of your home [sided-stucco] is called a Chase.

Chase – Typically contains metal flues, and a metal [many are galvanized] chase cover where the flues pass through at the top. Over time this chase cover can rot which can cause leaking into the fireplace and or basement, also can cause the wooden chase to rot if not addressed.

Flue– Straw/Tube[s] contained within a chimney used to exhaust fumes from fireplaces, furnaces and gas/wood/pellet stoves. Most modern homes are built with terracotta flue[s] or those with chase chimneys will have a metal flue. Typically a home with a furnace and fireplace will have 1-chimney with 2 flues contained within.

Liner [used interchangeably with flue]– Terracotta, Aluminum or Stainless Steel. Older homes were not built with liners, they are typically brick or cinderblock chimney with a cavity. Over time the mortar breaks down and can allow dangerous fumes [Carbon monoxide] to penetrate your home.

  • Terracotta liners are comprised typically of rectangular sections that are stacked vertically, many are dry stacked [no mortar between the sections] over time can pit, crack, shift also chimney fires can damage. In both cases it may require relining.
  • Many Hi-Efficiency furnaces may require a terracotta lined chimney to be relined with stainless steel. Check your manual and local building inspector’s requirements.
  • If you go to a Direct Vent / Power Vent heating system and leave an existing hot water heater using the shared flue. The draft from the hot water heater alone is minimal. Generally the hot water heater is no longer able to draft completely up the flue. Which cause fumes [Carbon Monoxide] to backup into the home where the hot water heater is located [typically basement/garage area]. A smaller liner needs to be installed.
  • Re-lining is typically done using stainless steel or aluminum. Stainless steel typically has a lifetime warranty whereas aluminum has a limited time warranty. Woodstoves and oil must use stainless steel. An oil furnace being exchanged for a gas furnace should have the flue lined with stainless. The emissions that linger on the flue from the oil will interact with the new gas furnaces emissions, causing accelerated deterioration of the existing flue liner.

Flue Partition – Many older homes with flues running parallel in the same chimney were not built with a partition. This is now code issue in Massachusetts. A partition is required between the flues so a breach in one cannot use the other flue as access to the home occupants [Carbon Monoxide issue].

  • EXP: A breach [break/shift/crack] occurs in the furnace flue, the exhaust from the furnace seeps into the chimney cavity, the furnace fumes can enter between the terracotta stacked tiles of the fireplace flue which is running parallel with the furnace flue in the same chimney. This will allow fumes [Carbon Monoxide] to spill out the fireplace opening into the living space. A flue partition is present to prevent this exchange.
  • Metal Stack Chimney – Insulated metal pipe, installed alongside the exterior of your home to above the roofline. Typically installed for wood stoves and when Power Vent/Direct Vent systems fail. Direct vent pellet stoves also use a modified version [much shorter and smaller diameter]. These can be boxed in by a carpenter if so desired.

Damper – Located within the fireplace, at the ceiling of the fireplace and the bottom of the fireplace flue. Used to regulate the airflow [draft] in fireplaces. Wood and Pellet Stoves can also have pipe dampers, used to regulate airflow.

Two basic styles: 

  • Poker Style – Reach in fireplace and pivot a handle.
  • Rotary Style – Small turn knob located on fireplace façade.

Tuckpoint/Repoint – The process of removing loose mortar in masonry joints, generally by grinding and then replacing with new mortar.

Crown – Located on the top of a masonry chimney, comprised of mortar/cement, it is typically pitched to allow rain/snow to roll off. If the crown becomes cracked, is not correctly pitched, water can collect causing cracking/pitting which can allow leakage into the house.

Chimney Cap – Placed atop a chimney over the flue[s], protection against pitting, crown deterioration, water dripping in and keeping critters out. Water [rain-snow-humidity] over time will cause deterioration and the need to reline. [The difference is; hundred[s] for a chimney cap vs a few thousand for flue relining].

An open [unprotected, no cap] flue is an invitation for a bird, squirrel and raccoon to nest [yes they can fit]. The warm furnace flue running parallel to an unused or barely used fireplace flue is a perfect place to raise a family. The chirping, squeaking you hear in the Spring could be a flue nursery! Who wants to come home to a frightened baby [raccoon or squirrel] running around your family room. The damage they can cause is vast.

Fireplace Forms – These are wooden frames that were used when the house was constructed. They were ‘supposed’ to be removed at that time, many were not.

In Massachusetts it is against code to have them, a fire hazard. Wood located beneath a fireplace is seemingly safe until a breach in mortar occurs then cinders can ignite the wood beneath. Upon a home sale is when many are detected and must be removed.

Wood and Pellet Stoves – These can be great alternative sources of heat. They come as free standing or inserts. Research your liner options; full liner vs partial liner. The difference is very important if you have an end chimney [Chimney with exposed sides vs enclosed by your home]. Check with your local inspector as to what is needed when pulling the installation permit and installation requirements.

  • Important: Wood or pellet stoves located in a home you are purchasing should be inspected by a qualified licensed professional. Also if the chimney ‘HAD’ a wood stove be sure the flue has been maintained and no flue issues are present, as well as the damper is in place and working. [Many installers remove the damper or the plate(s) when the initial stove install was done].

Gas Insert vs Gas Logs – A nice addition to any home however be aware that gas inserts/fireplaces are vastly different. In both cases the damper must be removed or locked open, per code. This is a safety feature should there be a malfunction.

  • Gas logs having the required damper alteration are always open to the weather. When there is a windy/drafty/humid day the air flow down the flue is not impeded, which can cause a draft into the room. Glass doors can help.
  • Gas insert/fireplace is a sealed unit and has its own liner and return system, drafts are minimal if any.

Creosote – The by-product of wood burning, it is black or brown in appearance. It can be crusty and flaky…tar-like, drippy and sticky…or shiny and hardened IN ANY CASE is highly flammable.

A flue with third degree creosote build-up [thick shiny] must be cleaned by an alternate method. An inexperienced chimney sweep that uses the standard method [brushes] to clean this type of build-up. Will only scratch-up the surface of the creosote layer, causing ridges and irregular surface. This is a perfect set-up for a chimney fire.

An ember or spark finds the channels created by the brushes and then you hear what appears to be a freight train in your chimney. DO NOT shut the damper, call the fire department!

  • Avoid / minimize creosote buildup: use hardwoods and properly seasoned wood. Burn your fire hot, a slow burning cooler fire creates more creosote. A slow burn swirls more leaving excessive residue on the flue tile surface. No one wants a chimney fire!
Before every burning season have your chimney inspected, to avoid year to year buildup.

Waterproofing – A liquid membrane applied to masonry that seals minor cracks and voids where water can be infiltrate. As masonry ages it becomes more porous, taking on water like a sponge. Waterproofing a chimney adds a layer of additional protection to older bricks.

We use ChimneySaver is a ‘water repellent’ not a ‘water sealer’. Water sealers remain on the surface and trap water vapor.

ChimneySaver penetrates deep enough to protect from water penetration, it is breathable membrane. ChimneySaver has a 10 year manufacturer’s warranty.

Side view of completed Chimney. New lead flashing, new stainless chimney cap and liner.

New Stainless Chase Cover, notice pitched top not flat.

Unlined flue found in many older homes. No damper.