Chapter 3: Fireplaces

A basic understanding of how fireplaces work will maximize your enjoyment and help prevent problems. In this section we will cover:

• Types of Fireplaces
• Anatomy of a Fireplace
• How to Use the Fireplace
• Fireplace Accessories

All fireplaces are not created equal. In fact, other than factory-built fireplaces, no two fireplaces are the same. Even if your fireplace seems identical to your neighbor's (suppose, for instance, that you both bought the same model of factory built fireplace) they can behave very differently depending on how you use them.

Armed with some basic knowledge about the "hardware," you will have better success in making your fireplace behave itself.

Traditional masonry fireplaces fall into two general categories:

Standard Fireplaces. A normal brick fireplace, most of which have an opening about 36" wide, about 28" high, and are 16" to 20" deep. The inner walls of the fireplace angle inward, and the back sometimes slopes forward a bit, but is sometimes nearly vertical.

Rumford Fireplaces. Count Rumford (Sir Benjamin Thompson), an 18th century philosopher and scientist, wrote a book on fireplace design that stands in stark contrast to the "standard" design. Designed to increase heat transfer to the room (and thus reduce heat loss up the flue), Rumford fireplaces incorporate a shallower firebox and a higher opening, with the sides and back quite slanted. These fireplaces often look as if they would certainly spill smoke into the room. But a properly constructed Rumford fireplace does, in fact, deliver what Count Rumford promises. If you are designing a new home, talk to an experienced mason about it.

The art of building Rumford fireplaces was almost lost; but modern masons are starting to look once more at his design, and Rumford fireplaces are finding their way more frequently into new homes.

Some newer types of fireplaces include:

Factory-built Fireplaces. Fireplaces built in a factory, of steel, cast iron, firebrick, and other manufactured materials, and installed on site, generally with factory-built chimneys.

Masonry fireplaces with metal liners. Standard brick or stone fireplaces incorporating a cast-iron or steel lining inside the fireplace.

Sometimes the metal liner incorporates an air space between two layers of metal. Ducts connected to this air space (usually you will see a grate on either side of the fireplace opening near the floor) draw cool air in at the base and vent warm air out higher (usually through another pair of grates above the mantel).

Modular/masonry fireplaces. A relatively new addition to the lineup, modular masonry fireplaces are built of pre- fabricated masonry sections, which are assembled on-site. Some systems are designed for retro-fitting to existing chimneys, as a replacement system for a damaged or non-functional fireplace.

While there are differences among the various types of fireplaces, you will find several common parts. An understanding of the basic terminology is helpful.

Outer Hearth. This is the technical term for what we usually call the hearth. It is the part of the hearth that extends out into the room, beyond the fireplace opening.

Inner Hearth. The floor of the fireplace, inside the opening.

Firebox. This is where you build the fire.

Fireback. The rear wall of the firebox.

Damper. A plate or valve that closes the fireplace flue when the fireplace is not in use. You must fully open it before lighting the fire.

Throat damper. A damper located in the throat of the fireplace, just above the firebox. This is the kind found in most fireplaces, and is operated by means of either (a) a handle inside the firebox or (b) a knob above the fireplace opening connected to a rotating metal shaft attached to the damper.

Top-sealing damper. A damper located at the top of the chimney, operated by means of a cable extending down the flue to a handle in the firebox.

Smoke Chamber. The roughly-triangular space above the throat of the fireplace leading up to the flue.

Flue. The vertical passageway up the inside of the chimney.

Ash dump door. A metal door located in the inner hearth of some fireplaces, which leads to an ash pit.

Ash Pit. A cavity underneath a fireplace firebox, used as a receptacle for ashes, and accessible for cleanout by means of a cleanout door.

Ash pit cleanout door. A metal door located at the base of the chimney which leads to the ash pit, facilitating cleanout of the ash pit.

If you have never used the fireplace before, or if it has been over a year since you have had it checked by a professional, have your chimney professional check the fireplace and chimney before you use it. (See page 8 for information on choosing a chimney professional and having the chimney checked.)

Ask him/her about how the damper works, and for any observations that might point to potential problems with the fireplace. Chimney professionals are trained to check the venting system and spot possible hazards that a layman would miss.

Essentially, using the fireplace is a matter of opening the damper, setting the fire, and lighting it – there's not much to it! A day or so later, when the fire is completely out, including the coal bed, you should close the damper again, to prevent heat loss up the flue.

But before you start your first fire, read about Fire Safety and How to Build a Fire, starting on page 15.

Tools. A good set of fireplace tools is a necessity, of course. At minimum, you will want a poker, a hearth broom, and a shovel for ash cleanup. Other useful tools include a set of tongs for moving logs, and a hoe for moving ashes around (especially useful in pushing ashes into the ash pit).

Some people also like a bellows, for blowing air into the coal bed to start a faltering fire (and for decoration).

Grate. Building fires directly on the inner hearth isn't a good idea, unless you have a factory-built fireplace that's specifically designed without a grate. Fires built right on the floor of the firebox don't usually burn as well, since it is harder for air to get in. Also premature wear to the inner hearth might occur.

If you don't have a grate, take measurements of the inner hearth's depth, width in front, and width in back. Go to your local stove shop and pick one out. A heavy cast-iron grate will last much longer than a grate made of welded steel bars. If you plan to use the fireplace often, spend a little extra for a good cast-iron grate.

Andirons. Some people use andirons in place of a grate. But as logs burn down, andirons will no longer hold the logs up. They will collapse to the floor of the firebox. So even if you have andirons, a grate is still a good idea. You can keep the andirons for decoration and ambiance. Just slide the rear legs under the grate, or put one on each side if they are too tall to fit under. You can also buy special short shanks for andirons at a stove shop. These are replacement rear assemblies for andirons (equivalent to the part you set the logs on) but they are very short front to back, so you can place the andirons fully in front of the grate. You just unbolt the old assembly and bolt these on instead. Bring one of your andirons to the stove shop so you can check to see if they will work before you buy them. Short shanks for andirons are also useful for people who have a shallow firebox and glass doors covering the fireplace opening. You can place the andirons with short shanks outside the doors on the hearth (just for decoration, of course)

Spark Screen. A must. You can choose from hanging mesh screens that slide open, rigid or folding screens that stand in front of the opening, or attached "gate" style screens. If you don't have a screen, or if yours is worn out, measure the height and width of the fireplace opening and the amount of clear space around the opening (the clearance to a mantel, or exterior damper handles, etc). Take your measurements to your local stove shop and pick one out.

Fireplace Doors. Highly recommended. These are tempered glass doors in a metal framework, sized to fit your fireplace opening. Most incorporate a hanging mesh or gate-style screen, and some sort of louvers to adjust air flow to the firebox when the doors are closed.

The main advantage of a set of fireplace doors is that you can close them before you go to bed, minimizing heat loss up the flue – because you can't close the damper until the fire is completely out, usually a day or more later.

Also, if the fireplace should start to smoke due to wind conditions or other problems, closing the doors will often prevent smoke from continuing to enter your home.

Some common types of fireplace problems can be solved with doors, as well. We will discuss these in the problem- solving section, starting on page 25.

A word of advice: Don't let sticker shock scare you away from purchasing a good set of doors. The quality difference between a $100 set and a $600 set is immense. The fireplace is the focus of your living room, and a valuable asset. Choose a set of doors that offers durability and beauty, and each time you use the fireplace, you will be glad you spent the extra money. A cheap set of doors will look good for a year or so, then drive you crazy as the doors buckle and bind, the finish wears off, and the focus of your living room turns into an eyesore.

Fireplace Inserts. Fireplaces are not designed to be efficient heaters. And in an effort to get more heat from a fireplace, some homeowners install a fireplace insert. There are several types of inserts available, from high-efficiency wood stoves designed to be installed in a fireplace, to hollow grates with a fan to circulate heat into the room.

If you are considering the installation of an insert, do some homework first, or you may be sorely disappointed.

First, decide what your expectations are. If you want this fireplace to heat your home, you will need a high-efficiency modern woodstove with enough power to heat the house.

In the 1970's we used to just slide a stove into the fireplace and light 'er up. But we found (often the hard way, through chimney fires and tragic losses) that this isn't a safe installation.

To install a woodstove properly and safely insert requires, at minimum, connecting the stove up through the smoke chamber and into the chimney liner, which usually starts five feet or more from the fireplace floor. This involves the use of listed chimney liner parts specifically designed for this purpose. Sometimes an entirely new liner is needed, to size the flue for the stove properly. In any case, this is a job for an expert. Go to your local stove shop and ask about an insert.

Bringing some basic measurements with you will help.

Note: Don't be discouraged if you can't get all these measurements. Your stove installer will probably want to visit and take exact measurements, anyway. This will simply help you get an idea of what will fit, and the cost.