Wood stove removal

[markbeas]

My house has a fireplace on the main floor and a wood fireplace directly below it in the basement which both share the same piping if you will. We removed the basement wood stove and my question is what do I use to fill in the pipe from the basement to the main floor fireplace as I'm wanting to finish our basement and there will be a wall built in that place and I want to prevent issues in future..

Can I just fill that hole with concrete in basement. Or do I need to use a different material... thank you in advance

 

[begreen]

Normally this is not permitted. Are you sure they share a common flue and not two flues in one chimney? What comes out at the top? One or two flue pipes?

You can brick in and cement the lower flue, but it would be nice to mark the location. If this is a separate flue some future homeowner might want to use it again.

 

[markbeas]

You are right. It's one chimney. 2 flumes going up through it

 

[markbeas]

We will do that with marking it....but the part in the basement we were told we need to fill the old flume that goes to the basement with thermix to fill it in.

 

[begreen]

That shouldn't be necessary. I would think just bricking it in would suffice.

 

[markbeas]

I didnt know if there was something else to put in the hole in the basement other than just a cap

 

[markbeas]

Ok. So I can just knock out this round flume. then fill in the hole. Last fall we had the chimney inspected when we bought the house and were told we having issues with negative pressure in the house

 

[peakbagger]

Negative pressure issues generally means you need a air to air heat exchanger installed in the home. That will improve indoor air quality and decrease negative pressure issues

 

[coaly]

Ok. So I can just knock out this round flume. then fill in the hole. Last fall we had the chimney inspected when we bought the house and were told we having issues with negative pressure in the house

Why would you want to destroy the round clay thimble? It's perfectly usable. Cap or plug it.
Google "Chimney thimble cover".
Then take care of the negative pressure issue.

Negative pressure means a blower or other appliances are pulling air out of the home. The pressure inside becomes lower than the atmosphere air pressure outside. So the chimney flue becomes the air intake that equalizes the pressure, bringing in the smell with the fresh air. This could be a number of things causing it. Kitchen range exhaust hood, bath fan, clothes dryer, gas or oil fired water heater, furnace or boiler especially with a power vent blowing indoor air outside. Also radon blowers if equipped...... any thing exhausting air to the outside. Next is any leak in the upper end of the home or attic. Heated air rises out any openings, vents, or open windows decreasing pressure inside.

The most common culprit is a utility room in basement with heating appliances venting to the outside. The room will have a ventilated door or no door allowing the appliance to use indoor air. This room needs its own air intake so it doesn't affect the rest of the house.

Any air tight cap will suffice. Keep it simple so it can be removed easily. The top should be screened to prevent birds or animals from nesting in it.

 

[markbeas]

Guess my big concern is I'm finishing my basement and I'm framing a bedroom wall in its place. And by just capping it off and framing it behind a finished wall with drywall is that we wont have any issues with using the main fireplace in the future since that hole wont be visible anymore. Yes I agree just capping it off would be way easier

 

[begreen]

Negative pressure can happen for a number of reasons. Competing exhaust appliances are one, other combustion devices are another. A third cause can be air leakage from the upper floors of the house. This can be caused by leaky windows, an unsealed attic door or ceiling vent to the attic.
The other thing that may have brought about the negative pressure comment is thermo-siphoning of smoke from the upstairs fireplace into the adjacent flue and being pulled down into the basement. This is commonly caused by both flues terminating at the chimney top at the same level. The fix is to raise the fireplace flue about 12" higher.
If this is going to be buried behind a wall, and thermo-siphoning is the issue, then seal it up with an actual pipe cap siliconed in place. But do make note of the location in case you sell the house. A future homeowner may want to solve the root issue and use that flue.