Stop the back draft

[GrumpyPawPaw]

Fairly large wood burning stone fireplace. If I don't have a roaring fire I can get a backdraft. Guess I'll have to put in sealed front glass doors? Who can make them custom, to fit?

[hearthman]

First of all, read the old threads here on smoking fireplaces and possibly remedy the situation. If this is a masonry fireplace meaning not a factory built fireplace with a stone front then you can go to your local hearth shop and have them make a template and order a custom enclosure. Be sure to have plenty of $$$.

If it is a factory built fireplace, you can only use the doors that are tested and listed for use with that make and model fireplace. This will be listed in the back of the instruction manual that came with your fireplace or your can contact your local dealer. Do NOT use aftermarket custom doors on a factory built fireplace. It often leads to an unfriendly fire meaning burn the house down and/ or injure or kill occupants.

[darthvader]

Also they make things called smoke guard, they don't always look the best but they can help a lot. When builders build big stone fireplaces they many time have these huge openings that the chimney can't support(cant draft all the air the opening provides) so you get back draft, by closing down the opening size you can reduce the back draft.

There is a ratio for sizing fireplace openings to chimneys. 10 to 1 is the accepted ratio, so for every 10 sq inches of fireplace opening you need 1 sq inches of flue to support the fireplace. I run into this a lot where the builder put in a huge fireplace only to have a normal flue. There are many causes for smoke/backdrafts. Like tightness of home, exhaust motors other fireplaces and temperature of home vs outside air temp and humidity.