Fireplace under construction

Jim,

I had a chance to talk a bit more with the home owners with the overheating mantle problem. It seems the problem of heating up the mantle only occurs when they've had a fire going for longer than a few hours, which they do on holidays and such. Apparently is getting to hot to even touch, and they are concerned it may actually start the place on fire.

Attached is a picture of the fireplace from during construction. I'll take a finished photo when I stop out there tomorrow and send that to you as well. Its a full masonry flue with cultured stone veneer, so I dont imagine the heat radiating through the flue wall, through the CMU, through the Stone, and into the wood mantle would be the problem.

Do you think it would be possible to fashion some sort of heat shield that would deflect the heat rising out of the front of the fireplace further out into the room so it would bypass the mantle as it rose?

Any other ideas or input?

Thanks again for the advice.

David Maxam

reckley associates architects

Thanks for the pictures. It doesn't look as if there are any combustibles except for the mantel and that's exposed so is at least not an insidious fire hazard.

The only thing that comes to my mind is the screen. Perhaps it's too close to the fireplace opening and diverts heat upward under the mantel or gets very hot and heats the mantel indirectly. Ask them to pull the screen out a foot farther and see if that has any effect.

Then there may be the issue of how hot is too hot. Code is generally built around the principle that combustibles should not get hotter than 90 degrees F above ambient temperature. That would be about 160 degrees F and would feel pretty hot but would still be well below the danger level. Maybe taping a kitchen thermometer to the bottom of the mantel shelf to see how hot it really is would be instructive. Maybe it's only 120 or 130 degrees which might feel pretty hot but would not be a fire hazard.

Best,
Jim Buckley