Permanently Seal a Chimney

[wwjdpilot]

I have gone to a Direct Vent gas insert that has been routed out the back wall of my chimney. The existing two story brick chimney is attached to my house on only one surface with the remaining three surfaces being exposed to the elements. The firebox is above ground level.
I don't plan on staying in this house forever, so it will need to pass some sort of home sale inspection. The firebox opening will be sealed with two layers of concrete wall board (hardibacker) with pressure treated lumber and insulation in between. The insert will be set directly in front of this with a new surround built for it.

My question is how to seal this existing chimney. Fiberglass insulation? A wool pad of sorts? Just block it at the top?

 

[pen]

I'd block it at the top. Lots of options for doing it, so long as they are removable with general ease.... Lots of chimneys sealed around here with a piece of bluestone one top and a bead silicone.

How soon are you to resale?

 

[EatenByLimestone]

As long as some nut doesn't try to start a fire in it, the top sealing is just fine. It sounds like the bottom will be sealed, so all should be good. I'd try to stuff enough insulation in there to stop it from pulling heat from the house.

 

[wwjdpilot]

I'd block it at the top. Lots of options for doing it, so long as they are removable with general ease.... Lots of chimneys sealed around here with a piece of bluestone one top and a bead silicone.

How soon are you to resale?

Thanks for the info. I have no idea how long I will be in this house. I guess once all of my projects are completed and I get bored, the house will be ready for its next owner.

 

[wwjdpilot]

As long as some nut doesn't try to start a fire in it, the top sealing is just fine. It sounds like the bottom will be sealed, so all should be good. I'd try to stuff enough insulation in there to stop it from pulling heat from the house.

Thanks EatenByLimestone. My Direct Vent fireplace will have a new surround with stone installed around it, so someone would need to dismantle it and fix the hole out the back of the firebox before they could start a fire in it, but I'm sure someone could figure out a way to make that happen too.