I have been building masonry fireplaces for about 20 years.

Let's start with that- there is a huge difference between a wood burning steel box, and a masonry fireplace. We are going to call the first a wood burning stove, the second is a fireplace!

A wood burning stove vents differently-it usually has some kind of ability to mechanically put the heat back into the room, and commonly has a gas lighter.

A full masonry fireplace actually draws cold air from the chimney as it vents the hot air. This is done with the "smoke shelf," an area behind the opening of the damper that allows the cold air to "curl" the hot air and allows it to rise.

The is a big important part of both- and that is they BOTH draw a considerable amount of air (oxygen) while burning a wood fire. A good masonry fireplace will have an external air vent. The biggest issue I hear is, "My firepalce smokes into the house, so I dont use it" and commonly- for the same reason a wood burning stove does.

A fire needs to start small and slowly build heat.

In a masonry fireplace this is imperative! Everybody knows cold air sinks, hot air rises, but consider the extremely cold, especially in a midwest winter- (compared to the interior of the house) masonry surface in the interior of the flus, throat, smokeshelf and firebox.

There is a LOT of cold air coming down the chimney- and where there is big fire- there is big smoke- and if its too cold to rise-the cold will push it right back into the house.

So here is your new method. Make kindeling, make small split logs, and build your fire slowly, from 1" to 2" and on up. There are few fireplaces that can handle an unsplit 5" log instantly! If you have a gas log lighter- let it run for 5 minutes before even starting the wood, and never try to start a batch of 3" logs with the log lighter.

There are some additional problem with newer high efficiency homes, with airtight windows and doors. If you have additional questions, please ask!