Having been in the chimney business for so long, I have come to realize how widespread the issue of poor draft is all across the country. Poor chimney draft can be extremely frustrating, especially when you light a fire in the fireplace and you get smoke pouring into your living room. There are many steps you can take to fix such a problem, but understanding the cause of a chimney draft problem is the key.
The root of your chimney draft problem may be one of many. To start with, you may be lighting a fire that is too hot and expecting it to vent up a flue that is too cold. If this is the case then fixing the problem can be quite easy. Prior to lighting your fire burn newspaper, holding it up in the flue system to allow the flue to warm up. Do cautiously of course and wear protective eyewear and gloves.
Another common problem lies in the chimney height. If the chimney is not tall enough to create a good draft then problems can arise. A chimney must be a certain height in proportion to the size of the firebox in order for optimum draw to occur. The width times the height of the firebox cannot exceed ten times the flue opening. These dimensions should be two to three times the depth of the fireplace and the width of the back of the firebox and the firebox’s depth should be equal. If your dimensions do not reflect these recommended dimensions you may want to consider purchasing a Smoke Guard, a metal strip that you attach to the front of the firebox to change it’s dimensions. A way to test to see if a Smoke Guard will resolve your issue is to tape aluminum foil to the top boo make the firebox smaller.
If you or a professional determine that the height of your chimney is not sufficient to create proper draft and resizing the firebox using a Smoke Guard does not help you may have to make the investment of adding few courses of brick to the chimney. This is an expensive endeavor compared to the other options. Your existing chimney crown will have to be removed, courses of brick added, and the crown replaced. If you are committed to resolving your draft problem this solution is what you may have to resort to.
Consulting with a professional before making any expensive repairs to your fireplace will prevent you from wasting money as well as ensuring that whichever step you choose to try to stop your draft problem is the most appropriate for your situation. Remember that tall trees very near the chimney or other tall structures near the top of the chimney may affect the draft. Take all factors into account before making any decisions and follow any and all building and fire codes in your area.