Knowledge Center

Our Knowledge Center in Potomac Mills, VA is designed to give you general information and answer basic questions about the fireplace and chimney systems. We are constantly updating this page because knowledge is power— so check back from time to time as this section will be constantly evolving.

Wood Stove Insert

If you have a wood stove insert in your chimney, there will be an extra cost. This additional cost is due to the increased difficulty of sweeping or inspecting a chimney that includes a wood stove insert. Wood stove inserts are extremely heavy and require extra time and effort to move. However, if you have a properly lined wood stove insert that does not require movement then there will be no additional cost.

Free Standing Wood Stove

Free standing wood stoves are less difficult to sweep than wood stove inserts,

but they still require disconnection in order to reach the chimney, which necessitates extra time and effort on the part of our technicians. If, however, you have a free standing wood stove that does not interfere with reaching your chimney, you will not be charged an additional fee.

Wood

  • How much wood is in a cord? The cord is the standard measure of volume used for stacked wood. The volume of one cord of wood is 128 cubic feet of stacked wood. Generally, a cord is laid out in stacks that measure 4 feet wide, 4 feet tall, and 8 feet long (4’ x 4’ x 8’) in total. Due to air space between the stacked wood, the volume of solid wood in a cord may be only 70 to 90 cubic feet.
  • Cutting wood: Freshly cut wood contains up to 50 percent moisture and must be seasoned (dried) to 20 to 25 percent moisture content before burning. Wood containing more than 25 percent moisture is wet, or green, and should never be burned in a fireplace or wood stove.
  • Splitting wood: Wet wood is easier to split than dry wood. Wood must be split into pieces and stacked out of the rain for at least six months to season properly.
  • Seasoning firewood: If steam bubbles and hisses out of the end grain as the firewood heats up on the fire, the wood is wet, or green, and needs to be seasoned longer before burning. Well-seasoned firewood generally has darkened ends with visible cracks or splits. It is relatively lightweight and makes a sharp, distinctive “clink” when two pieces strike each other.

Starting a Fire

  • Make sure your chimney is clean and free of blockages. It’s always a good idea to get your chimney swept before you start lighting fires in it. Even if you haven’t used it, animal nests and old leaves can cause blockages that will result in a smoke-filled house.
  • Open the damper. Make sure to open the damper all the way before atempting to light a fire.
  • Prime the flue. If your chimney is built on the outside of your house, the chimney flue is probably cold. When you open the damper, the cold air in the flue will sink and come into your warm house. If you try to light a fire during this air sink, you’re going to end up with smoke coming into the house instead of up the chimney. To counteract the air sink, you need to prime the flue by warming it up. This is done by lighting a roll of newspaper and holding it up the damper opening for a few minutes. When you feel the draft reverse, you know the flue is primed, and you’re ready to start your fire.

Masonry Chimney Diagram

Masonry fireplaces, built of bricks, blocks or stone and mortar, are massive structures often weighing between 6 or more tons! They are aesthetically pleasing, long lasting, and add real value to your home. With a little care and periodic maintenance they can give you a lifetime of enjoyment.

Prefabricated Chimney Diagram

​Factory built, or prefabricated fireplaces, are relative newcomers to the fireplace scene. Unlike traditional masonry fireplaces, most factory built fireplaces are metal, and come from the factory as complete units with a firebox, a specific chimney system, and all miscellaneous parts. With proper installation and maintenance, they can give years of service,

Chimney Basics

In order to produce draft, a chimney must contain hot flue gases. Both to maintain the temperature of those gases and to prevent excessive heat from reaching the outside of the chimney and its surroundings, a chimney must be designed and constructed to minimize heat loss.

Residential masonry chimneys are defined by their ability to operate satisfactorily and protect the building while under exposure to continuous flue gas temperatures up to 1000°F. Chimney design, however, must anticipate both appliance malfunction and operator error.

Flue Lining

Flue lining plays a critical role in containing the products of combustion and minimizing heat transfer to the chimney wall. There are a number of different materials and forms used for this purpose, but by far the most common is vitreous clay flue lining.

 

“13.9 Damaged or Deteriorated Liners. If the flue liner in a masonry chimney has softened, cracked, or otherwise deteriorated so that it no longer has the continued ability to contain the products of combustion, (ie. heat, moisture, creosote, and flue gases), it shall be either removed and replaced, repaired, or relined with a listed liner system or other approved material that will resist corrosion, softening, or cracking from flue gases at temperatures appropriate to the class of chimney service

Chimney Crown (Cap, Splay, or Wash)

The purpose of the chimney crown is to close off the space between the flue liner and chimney wall, to shed rainwater clear of the chimney, and generally to prevent the entry of moisture. Despite its importance to the integrity of the chimney, this is one feature that is neither well- addressed in codes nor well-executed in the field. Failed or inadequate chimney crowns are among the more common causes of chimney deterioration.

Chimney Fires

Chimney fires are among the more common types of fire incidents reported in the United States, so it follows that they have been experienced by a large number of people. Indications of a chimney fire have been described as creating:

  • Loud cracking and popping noise
  • A lot of dense smoke
  • An intense, burning smell

​Chimney fires can burn explosively – noisy and dramatic enough to be detected by neighbors or passersby. Flames or dense smoke may shoot from the top of the chimney. Homeowners report being startled by a low rumbling sound that reminds them of a freight train or a low flying airplane. However, those are only the chimney fires you know about.