Tile for gas fireplace?

[krw]

I have a gas log fireplace (metal prefab box) that had tile fireplace opening. The builder just tiled over the steel firebox (outside/front) and the first time we fired up the gas logs tiles came off (apparently mortar doesn't stick to steel very well ;-).

I want to tear it all out and replace the tile but I certainly don't want this to happen again. My first idea was to pull down the tile and cover fireplace opening (part of the wall between the mantle and firebox) with Hardiebacker before re tiling. To get things to come out right, about an inch of the Hardiebacker will be exposed on the back side. Anyone see any issues with this. Better ideas?

[Don Phillipson]

This is the sort of problem the US National Bureau of Standards began investigating in the 1920s. Information is also on file at the Undewriters Laboratory and other issuers of building standards.

[krw]

Now there's a non-answer. Thanks.

[hrhofmann]

Can you tell anything about the previously used mastic that failed??? Have you talked about this at a local tile store or maybe a fireplace store?

[krw]

It was mortar ("apparently mortar doesn't stick to steel very well"). It's fine where it's stuck to (presumably) wall board. The first time I fired it up, with the gas logs in it, the tiles popped off as it cooled. There is obviously a thermal expansion problem between the steel fireplace and the tile (actually tumbled marble, I think). I was planning on putting natural stone (some sort of quartz) back up there.

Haven't yet but it's a good idea. I hate wasting their (fireplace store) time since it's unlikely they'll get a sale from this.

[hrhofmann]

Yes, but if they give you good information, you can tell other folks how good they are and maybe they will have more sales, so unless they are busy, not likely this time of year, they should be willing to help you out.

[Joe]

What did your lawyer say to the builder who screwed it up to begin with? And have you checked with City Hall for proper code compliant methods for such an installation?

Joe

[krw]

Another less than helpful answer. Why don't you leave it at home?

[krw]

It's certainly worth a try. Thanks. It's a real fireplace with gas logs, so I doubt the surround is going to get all that hot.

[chaniarts]

the glass on my gas log fireplace is hot enough to cook on (as i learned placing my hand against it after it was on for a couple of hours).

[krw]

Sure, but try it with a roaring wood fire. ;-)

[chaniarts]

metal isn't a proper substrate for tile. the metal flexes and changes size when heated and cooling, so almost nothing solid will stick tiles to it. something flexible like high temp silicone might. mastic will melt. you'll have to provide a proper substrate (brick, block, cement board, etc) for this application.

[krw]

Agreed. Of course I didn't know what was under the tile until I fired it up. My idea was to use Hardiebacker to cover the wall and metal fireplace, then tile (stone, actually) over that. Hardiebacker is rated for use on fireplaces but I'd need to have about 1" exposed on the back side (towards the fire) to get the tile to come out right.

[hrhofmann]

I used 5/8 sheetrock around my fireplace, a Preway prebuilt Heatolator fireplace. I used 4 inch square tiles on the entire front except on the metal front edge right around the glass doors, the black painted metal shows about 1.5 inches around the glass doors and then the tile begins. Send me you r e-mail and I'll send you a picture of what it looks like. Nothing fancy, but it is 15 years old and nothing ever happpened, and we have had many many fies in it over that time.

[krw]

There is only about 2-1/2 on the sides between the firebox and the mantle supports and there is at least 4" of metal above the firebox. There is no glass on the front (though that's another idea - have to think about it) to hide the metal, just a chain fire-screen. I think the exposed metal would look dumb.

The fireplace in this house is quite similar but has what looks like marble around the firebox; one large piece under the mantle and three smaller pieces on the sides and bottom. This would work, too, since there would be support for the bottom edge of the marble (from above). I wonder what the cost of that much marble (or whatever) would be?

My email address isn't hidden well. Your ideas are really appreciated. Thanks!

[RonB]

I cannot speak to your specific case but Hardibacker is often used to face = off wood burning inserts. We installed a Buckmaster in our new home a few = years ago and a dealer gave us shop sketches and some verbal instructions f= or facing. Basically it amounted to cutting the backer board to the shape = we wanted tiled; and screwing it to the face of the stove with stainless st= eel self tapping screws. BUT - The sketch and instructions were specific t= o the Buckmaster and ensured the screws did not penetrate directly into the= open fire box. They were confined to edge flanges, an area around the upp= er blower-fed heat vent and a lip near the door. The backer board and tile= did leave a 1-1/2" to 2" strip of black metal visible around the door. I = also used some plated tile edging to dress the edges of the board. There w= as NO adhesive of any kind between the metal face and the backer board

Again - this is an approved installation for a high efficiency wood burning= insert that was approved by the dealer, with a couple of modifications fro= m a factory suggestion. I would strongly suggest you contact the manufactu= rer or a local rep to get their suggestion. Some installers have been know= n to try to adhere backer board to the metal face with high temp adhesive a= nd no fasteners. Some people have had the entire tile face, with backer, f= all into the living room. That can be an unpleasant surprise when some of = the debris might be close to 500 degrees.

RonB

[chaniarts]

a cheap source of marble/granite is kitchen sink cutouts. i get stacks of them from counter manufacturers for free, as they have to pay to send them to the dump. it's pretty easy to cut with a normal diamond tile saw, or i've even used a 5" diamond blade in a HF side grinder. you'd have to also polish the edges, unless you're going for rustic, or had access to the proper polishing tools.

if you have enough glued to the wall, you can just overhang a little bit over the metal without anything, or any adhesive, behind it.

[krw]

I have a couple of wet saws so cutting it up is no problem. Countertops are a little on the thick side, though. It would make a pretty heavy wall.

I could probably even pay a kitchen place to finish them. The problem I see is getting them to match. The cost is intriguing, though.

The metal across the top is at least 4" wide (that's what I can see now and there is more above the second course). That's why I wanted to cover it with Hardiebacker, so there would be some support for the "tiles" over metal.

[chaniarts]

they make countertop overlays, which are pretty thin, but lots harder to find scraps of. you might contact someone near you that does this and wait for larger pieces of scrap to come available. he'd usually toss most of the extra because it likely won't match his next job.

if the bottom of the stone is resting on something, the weight bearing won't matter to the wall as long as the adhesive holds. it's a sheer rather than pulling force.

last time i looked about 5 years ago, it was $1/running inch for polishing a simple flat edge for 2mm granite. if you want a profile, it might be more.

i had to diamond hone the tops/sides of some concrete countertops that i made, so i bought the tooling to do this. i've seen people buy the tooling, use once, and sell on ebay cheaply. if you need a link to the tooling let me know.

if you have access to a air powered needle scaler, you can make a rough edge on the stone and won't have to polish it.

i'd want at least a 3x section attached to the wall, so for a 4" unsupported overhang, i'd want at least 12" attached to the wall. that's a pretty wide tile, although a 12x12 or 12x24" tile would work.

[krw]

Yeah, there are some pretty big kitchen and bath places around here (like any big city, I suppose). We've been wanting to go in and look around (some time soon we're going to rebuild the master bathroom). Maybe I'll wander in and ask about scraps. As you hint, here, though. One job has to have enough scraps to do the whole thing. The fireplace front is 4' x 4', so that's a lot of "scrap".

The edges would rest on the stone on the side (about 3" on each side) but the middle wouldn't be supported at all.

That would certainly run the bill up. I really don't want to spend *that* much because we are going to sell the house sometime soon.

Another good idea. I'll have to weigh the alternatives.

I'm not familiar with that tool, but it sounds interesting. Ar, ar, arr.

There is about 20" above the fireplace to the mantle (by 48" wide) but tiles that large might look odd.