Fireplace Foam

[1961MGA]

I have a natural gas fireplace and a lot of cold air blows through the bottom of it. Is it okay to use spray foam to cover the wholes where the air blows through? Or is there another compound recommended?

 

[plow]

Sounds like a bad idea. Read the spray foam precautions.

 

[dfiler2]

You also may want to determine what the "holes" are for first.

 

[sselander]

If you determine the holes are unnecessary, I would think a firestop foam would be a safer alternative. 3M makes one.

 

[theoldwizard1]

The foam would be easy to install, but there are better products available.

 

[kamlung]

pic of said fireplace may help

 

[rlitman]

First, find the manufacturer's instructions for the fireplace. It is likely that the airflow is there by design. Do not seal anything without clear approval from the manufacturer!

If not, then Great Stuff sells an orange foam specifically as a fireblock.

 

[stealthmagic27]

What do you mean by holes? On this oldie in my house, those are for venting/drafting etc.. but on the right side there are slides of which you can open and close them...

 

[1961MGA]

I should haven clearer. There are 2 holes at the bottom of the fire place. 1 for the gas line and 1 is just empty but you can see the wood floor board. I do not believe they are for the exhaust as that would mean it would be blowing into the house.

 

[rburke65]

Ya..... A photo would really help.

 

[Ironhorse74]

I have a natural gas fireplace and a lot of cold air blows through the bottom of it. Is it okay to use spray foam to cover the wholes where the air blows through? Or is there another compound recommended?

No no and no again. The fireplace is not meant to stop drafts. That is the job of the building insulation and construction. Find out where the air is getting into the framing and plug that.

 

[75gmck25]

Assuming you figure out whether should really plug those holes, I would look at fire-rated caulk instead of spray foam. Even if the foam is fire-rated, its hard to control the dispersal and it often plugs up more than you plan for. Caulk must be pushed into place and it is usually not self-expanding, so you have more control over where it goes.

Bruce

 

[larry4406]

Sounds like he has a pre-engineered natural gas fireplace. On the units my company installs in our houses, at the bottom of the fireplace, there is a small 3-4" tall metal cavity under the firebox where the gas line and solenoid valves are located. At the sides and rear of this cavity are various knockouts for gas, line voltage, low voltage wiring etc. These can all be sealed.

Combustion air for these fireplaces enters from the front of the fireplace (i.e., the room being heated) and not the holes described above.

Note also, that if your fireplace is not running, then there is not a natural draft from this combustion air source and you could be getting back drafts thru the flue on high wind days. This happens on some of our houses. Even our electronic ignition fireplaces have a pilot light mode which can be initiated to ensure a positive draft and eliminate the back draft on high wind days.

All fireplaces are different, so the recommendation to read your specific manual is spot on.