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How to best seal off fireplace?

xvimbi's Avatar

Join Date: Jan 2010
Posts: 55

01-27-10, 06:04 AM   #1  
How to best seal off fireplace?

Hi - In my quest for stuffing all holes where cold air is coming in (and warm air is escaping), I have currently turned my attention to our gas fireplace.

The builders did not insulate the doghouse, i.e., the space behind and around the fireplace, or they did a very poor job, as cold air is streaming in through the bottom and top grilles as well as the gaps on the sides. The fireplace box itself is sealed except for the opening at the bottom where the gas line is. The vent cover seems to be working OK, i.e., there is almost no air coming out of the sealed box. I believe the cold air is simply coming through the walls, as supported by the fact that cold air is streaming out of the power outlets right next to the fireplace as well.

We are not using the fireplace, and so we are thinking of sealing it somehow, but not permanently. Our favored solution currently is to get a piece of thick glass, put weatherstripping around the edges and fit it snuggly into the wooden frame that surrounds the fireplace, from the bottom to the underside of the mantle. We would put some pins into the frame to secure the glass sheet and prevent it from falling out.

I realize that glass may not be the best insulator (unless we use some special glass), but we need to find a balance between effectiveness and esthetics. We still want to be able to see the fireplace. At least there won't be any air coming out.

Anything wrong with the idea? Are there other solutions that come to mind?

Thanks for letting me bounce our idea off.

Cheers - MM

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VC-Racing's Avatar

Join Date: Jun 2005
Posts: 219

01-27-10, 05:41 PM   #2  
Cove the top of the flue with something. I took some 3/4 treated plywood cut it to fit and used silicon caulk to hold it in place. Mines been there for 8yrs and no problems.

dan0661's Avatar

Join Date: Jan 2010
Posts: 376

01-30-10, 02:46 PM   #3  
Check with the installation specs to see how close the unit and flue pipe can be to combustable material then insulate the dog house. It would be nice if it is also finished (sheetrocked and clean) inside there. Sound like you have grills on the wall to get some heat from the fireplace. Air is heated, exits the upper grills and new air enters the lower grills. If the unit has a damper, close it. I have seen plexiglass front covers people have made to keep the draft down. Shut the gas valve off and make a tag for it stating what need to be done for the unit to operate again, just in case someone else should lite the fireplace.

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