I have a fireplace on the first floor and whenever I have a fire, the cellar smokes up like crazy. It appears there is another flue that could be hooked up to a wood stove in the cellar but the hole is covered up. How do I fix this?

I am a mason/chimmney expert. So far you have a firepalce first floor a crock hole in basemsnt . 101 chimmneys. The fireplace has to have its own flue by law so it works right and has its own dectiacted exaust. Now the hole in the basement does it have an old tin covering the opening? Look at your chimmney top outside. How many flues are sticking out? Do you have a boiler or furnace that uses a chimmney. Can you identify closely where the smell in the basment starts from. Also does your fireplace have a medal flip door inside the firebox for ash dump or added air flow for the firebox. Be careful smoke means gases and hot sparks travel. I need more information.