[jord1981]

I am in the process of insulating the unfinished portion of my basement. I currently have a natural gas forced air furnace, however there are traces of an old heating system in the basement. There are two flue entrances that are not in use. Can I simply insulate over these, or should I seal them somehow first?

My method of insulation is attaching R-10 rigid codeboard insulation to the foundation wall with adhesive, then building a 2x4 wall in front of the codeboard and filling it with R-12 batt insulation.

Any help would be appreciated.

 

[Ron6519]

My definition of a flue, is a pipe that enters the chimney. Is that what you're referring to?
Ron

 

[jord1981]

Essentially yes, though the pipe has been long since removed. I am referring to the hole through which the pipe used to go to reach the chimney.

 

[Ron6519]

Essentially yes, though the pipe has been long since removed. I am referring to the hole through which the pipe used to go to reach the chimney.

What you would do depends upon whether the flue is being used or has been abandoned.
If still active, I would get the proper sized cap for the hole and plug it up. Then you would caulk the perimeter with a high temp caulk or furnace cement. If inactive, you could put an insulating material inside that was not combustable.
Ron

 

[jord1981]

Thanks. In addition to the flue hole, there are two holes with doors that I would assume are soot clean outs - do I need to do anything special with these? Pictures attached.

 

[Ron6519]

Is there anything else using that flue?
Ron

 

[jord1981]

There is a fireplace upstairs, but it uses a separate flue in the same chimney.

 

[Ron6519]

Then I would cap the unused flue at the roof to keep out water, wind and animals.
You can insulate the flue entrance in the basement and seal it up.
Ron

 

[jord1981]

Thanks kindly for the advice. :thumbsup:

 

[jord1981]

What do I do with the two clean outs? Insulate and build over as well?

 

[Ron6519]

What do I do with the two clean outs? Insulate and build over as well?

Isn't one of the cleanouts for the fireplace? What do you mean by, "build over"? The abandoned cleanout can be sealed if you want. You can also insulate if you want.
Ron

 

[jord1981]

I am insulating the basement and building a 2x4 wall over the foundation wall - these clean outs would end up behind the wall.