Chimney Balloon

I have a row house 125 years and will not use the fireplace more. I put a safe home for natural gas in the basement instead. I'm going to seal the chimney top so more moisture can enter. How do I take? It has one of these caps round bricks. I thought a ball of fire in the top, then cover it with sheets bonded to sealing with cement. What the experts think?

I would do exactly the opposite. Make a metal cover on top that covers the crown if the rolls of the rain and the merits, there is a ball of fire in the fireplace. This way you will keep the moisture in the chimney and seal any air intake or projects from the bottom.

Use the red brick to seal the holes open and concrete mortar and bricks holding up.

Make sure that whoever is installing the new outbreaks have no plans to use the existing chimney for air intake and gas exhaust pipes. There are two pipes / tubes that are necessary to break through the roof to the gas fireplace.

If you want to be able to use the fireplace in the future try a fireplace plug. It seals the chimney close but can easily be removed if you ever want to use the fireplace.