fireplace mantel and heat deflector

[stevo wis]

Hi Folks,

We have a woodburning fireplace that we use as our primary heat that does heat the stone quite a bit above it. I would like to add a rustic wooden mantel above it and then mount a big tv. I have attached a photo with a cardboard template.
The fireplace minimums from the hearth mantel is 54" to bottom of mantel, but a little lower would be better. Also we need to keep the temperature above the mantel low to protect the tv. My thoughts are to have my buddy bend a piece of steel that is the width and depth of the mantel and bend the front edge up 45 degrees that could deflect the heat to pass the front of the mantel. I would install this with a 1/2 to 1" gap below the mantel as an air gap. There is not much commercially available except cement mantels at $1500+. What do you think of this idea?

Any suggestions?

thanks,
Stevo

[Patrick Varley]

I did something very similar. Couldn't find a heat deflector in the right size, so I found a local metal shop and they fabricated a piece for me. It extended to the edge of the mantel and then a 45 degree lip as you said. Painted it with Rust-Oleum High Heat paint, and then mounted it to the mantel with 1" ceramic spacers from McMaster. All in I think it was under $100. I'll add some pictures when I get home.

On a side note, that TV seems quite high...

[Russell Hayes]

My mantel gets hot on the bottom, but it hasn't affected the poly finish after three years.

On another note, that is really high for TV. You may get a sore neck. You might mock something up so you can try it first.

[jared herbert]

My son has a similar situation. Can you post a picture of your heat deflector so I can see how it is made? Thanks in advance

[Patrick Varley]

Here's some pictures. This is a ventless gas insert, and I confirmed distance to combustibles from the manufacturer. Per their specs, an 18 gauge (I think) with 1" air gap cut the distance in half. For a wood burning fireplace I suspect you'd have to check local fire codes.

These were the spacers I used:
https://www.mcmaster.com/96109A450

20220224_165916.jpg20220224_165904.jpg

[Dave Sabo]

I think you're over complicating this.

Wooden mantels have been above fireplaces since the middle ages ??? without metal heat shields.

[Jack Frederick]

I agree with Dave on this, I think I’d install the tv and just for you info get an infra-red temp gun to see how hot the mantel gets. If you find it alarming for any reason I think I’d try to find a piece of steel pipe that when quartered would lay against the bottom of the mantel. How far out does the mantel project?

[Patrick Varley]

I think you're over complicating this.

Wooden mantels have been above fireplaces since the middle ages ??? without metal heat shields.

There are a variety of variables that impact whether he's overcomplicating it. Sure, you can use a wood mantel as long as you satisfy minimum distance to combustibles. And the further the mantel projects, the farther away it has to be. Using a heat shield with an air gap decreases the required distance.

[Bill Dufour]

I would look at using a marble step or marble tiles in a welded support frame. Sheet copper looks nice by a fire.
Bill D.
We all know F 452 is the critical temperature thanks to Ray Bradbury.

[Carl Beckett]

I had a woodburning stove in a fireplace for years. A wooden mantel above that. It had a heat shield (sheet metal, with a lip that extended out past the mantel bent at an angle). The deflector is required by code in my area. It was painted flat black and was not obtrusive to look at.

It got pretty warm, I was never comfortable putting my TV there.

Fireplaces however are not the same since a lot of the heat goes up the chimney (some of the fireplace inserts are great to improve efficiency if you have that). The type of fireplace you have will impact the amount of heat that rises just in front.

[Wayne Cannon]

...
On another note, that is really high for TV. You may get a sore neck. You might mock something up so you can try it first.

Not to rain on anyone's parade; but heat is the #1 enemy of electronics. I'm sure TV designers assume their products will be mounted above fireplaces and account for the heat, but I wouldn't do it. I also agree with Russell's comment that above the mantel is too high for comfortable viewing -- albeit, an obvious place to fit a large TV into a home decor.

A thought: If you really want the TV above the fireplace, consider installing a quiet "muffin" fan (like used in electronics) in an unobtrusive location to the side (maybe even flush in of the mantel top with louvers) to gently blow cooler air laterally across the TV. It doesn't take much air flow to make a big temperature difference; and it will help circulate the warm fireplace air around the rest of the room.

Fireplace.jpg
You can see our TV is framed in a shallow recess in the wall beside the fireplace. Only about 1/3 is above the mantel's height, yet it is still a little too high for comfortable viewing (slightly, not terribly objectionable; but enough that we get a noticeably stiff neck after much viewing, though not enough to move it!). We are sitting 15-20 feet away. Closer is desirable for viewing, but would aggravate the height issue.

[Bob Cooper]

when i built my house i had the same worries though i chose not to put the TV over the mantel...for mostly usability reasons....not heat. But i was concerned w/heat in general. I have a wood stove and it gets exceptionally hot and puts out a ton of hot air. Last night i ran a fire and the top of the mantel after 2 hours was still cool to the touch so i personally wouldn't do anything special and just monitor it. I know my wife woudl not have wanted a piece of steal/iron under our mantel.

If you want i can take some measurements but here's a picture.

[Patrick Varley]

Not to belabor the point, but if you have a wooden mantel that projects far enough out, then it should be sufficient to "protect" the TV from heat as Bob C indicates. The question becomes whether you can safely get a wood mantel close enough to the fireplace to act as the shield while not then requiring your TV to be too high. The point of the heat shield is therefore to reduce the required distance to combustibles and protect the wood mantel from igniting (which can happen with extended exposure to 450 degrees).

[mark mcfarlane]

I just went through the same exercise and decided to use a steel mantle to allow me to get the TV lower. Did similar mockups to yours.

Your fireplace should come with a chart showing distances to combustible materials. The distance to a combustable mantle increases as the mantle gets deeper. If you don't do these measurements correctly and start your house on fire your insurance company may not pay.

One alternative for 'high' TVs is to use a 'pull down TV mount' such as these https://www.mantelmount.com/ which are designed specifically to pull a TV down and in front of a mantel/fireplace. It looks like your TV is maybe 7' off the floor so one of these pull down mantle mounts might be just the ticket. Then you can have the TV down all the time until you want a fire.

[Steve Rozmiarek]

Check your local code, but it is usually no mantle within 6" of opening, then a restricted mantle depth up to 12" with no restriction above. Mantle materials are presumed to be combustible for this, probably because most things that sit on a mantle are. Caveat, if the gas insert or firebox manufacturer requires something more restrictive, that becomes the rule. Code is interpreted differently by different inspectors and there is no one universal code version. Your local may be an older version of IBC, UBC or something I haven't heard of, so ask your local inspector.

I agree with Russel about the height of the TV being a neck killer, I personally discourage it on our builds for this and aesthetic reasons.