Metal studs for hearth pad

[steveb5004]

The more research I do, the more I think I want to frame my pad out of metal studs, cover in two layers of cement board with thin set in between, and cover with tile. But I've read some posts on here that say to not use the 24 gauge metal studs from Home Depot, Lowe's, etc. What kind of studs should I use (brand and/or gauge) and where can I get them? Links would be helpful.

I have a good pair of barn metal snips and a screw gun...please advise of what other tools I might need.

Many thanks in advance,
Steve

 

[realstihl]

None of the big box stores carry metal stubs here. They referred my to a drywall company. I curious what others have to say on this topic.

 

[webby3650]

A few around here have metal studs, but they are so flimsy! I sure wouldn't use them.
What is the purpose for the steel? Most new stoves only require ember protection.

 

[jeff_t]

Which stove? What is required for the hearth? Are metal studs going to make anything easier for you?

I have used those flimsy studs from Lowe's before. It wasn't my choice and I just kept my mouth shut for family peace, but I would never use them on my own. They are more or less a 24 ga C-channel, and aren't for load bearing applications, and definitely not for joists.

Menard's has steel framing. The other ones probably do, too, but it was easier for me to find them on Menard's site.
http://www.menards.com/main/buildin...ainwall-framing/p-2015056-c-5695.htm?tpt=5_en

I still like wood.

 

[steveb5004]

I was considering metal studs to help with the thermal barrier, although I just called the stove company (Buck Stove, model 74) and they said wood studs are fine as long as they're covered in the Durock, thinset and 1/4" tile.

 

[Jags]

If I didn't need the thermal protection of metal, I would avoid working with them for the hearth. 24 ga is for non-load bearing partition walls and designed to be installed vertically. They have NO strength in the horizontal position. If you just had to have steel and was going to go with a horizontal application I would suggest going to your friendly neighborhood drywall supplier (like the ones that contractors go to) and evaluate the 18ga stuff. They should also carry heavier ga if you think that was needed.
In the heavier gauges a steel cutoff saw is generally used.
(By the way - I am sitting in the corporate office of our friendly neighborhood drywall supply house )

 

[Dakotas Dad]

I did in fact use the light gauge ones from the home store, I did add in a couple turned sideways for extra strength/support. I have one of the heaviest stoves out there sitting on it now, and this winter, at least a few times had a couple people on the hearth after coming in from the zero degree temps, not a creak or shift or noise has ever been heard from the hearth. The stove I built the hearth for required a +6 R value..

When I was getting ready to start my build, I built a 16" x 16" box out of the studs using the same materials for the top and screwed it down to a piece of plywood. I then placed 400 pounds on it, and it didn't shift, creak, collapse, etc.

After 5 years, there has been no cracking of the grout, etc to show any movement, which is actually better than the tiles laid by the builder that were in front of the builders box fireplace we replaced.

 

[steveb5004]

Dakotas Dad, your conversion project looks wonderful...great job. I'm building a substantially larger pad -- 5' x 5' -- with a 460 lb. Buck Stove right in the middle. After calling the manufacturer, I'm convinced wood is the way to go for price, strength, and ease of working with. If it would improve the safety AT ALL I would go the hard route and use metal, but the manufacturer says it's completely unnecessary.

 

[Jags]

DD - I do not doubt your success, but I can also stand on an empty beer can without crushing it (I weigh 235 pounds).

I needed the exercises so I walked out to my steel racks. Here is the reality of a 24/25 ga stud:

I could have crushed this like a beer can.

 

[begreen]

Regardless of stud material, for additional rigidity I would put down a layer of 3/4" plywood on studs with 12" centers . Cement board should always have a backer board. If you go two layers of Durock, there is no gain or need for thinset between layers. Screw through both layers to the plywood every 8" and the bottom sheet will be totally captive and will lay flat. .

 

[Dakotas Dad]

Jags.. now, without bending it, crush it. Compression is different from deflection. You didn't crush anything, what you did was deform it. If it is/was held rigid properly, as it is when it is secured top and bottom, so it can't deflect.. well.. Heck a big guy should be able to do that to a much heavier gauge piece, I have bent 1/4 inch steel with a little leverage and my bare hands.. Just like the reason you can stand on a popcan.. as long as the vertical rib (in this case, can side) can't deflect, or doesn't get deflected.. it can hold a whole lot. In fact, since you have a stack, build a box like I described, 16" square, out of that stud material, then screw a top and bottom out of 1/2 ply or something, I think I ended up with 3 screws per linear foot, so it is a "six sided box".. I think you will be very surprised how hard it is to "crush", without deflecting it first. I stopped at a little over 400 lbs, because that FAR exceeded the load I was going to put on it. There is no doubt in my mind it would have held 10 times more. At the point I stopped, it was carrying a load of 235lbs per square foot, or almost 6 times the residential building code requirement for a floor load in a living room..

A plain old SPF 2x4 can hold a dozen tons as long as it doesn't deflect.. then 100 pounds or so may cause it to fail when it does deflect. Yet we still build houses that weigh tons out of them, and they stay standing... until they deflect. (which we all hope never happens of course)

SteveB.. I wouldn't use it for giggles, it WAS the answer for the hearth requirements of the Homestead. Your hearth pad will be 25sqft, mine is 22.. not that much bigger, and sqft doesn't matter as long as your c-to-c on the studs is appropriate. the stove sitting there now is +550lbs, and we have had 4 grown men on the hearth with it, so.. at least 1100 pounds.. no issue.

 

[Jags]

DD - I understand the deflection argument. That is why I used the can analogy. And if the hearth was/is built into a corner and securely anchored to the wall to eliminate any deflection, I am sure that the build would be sufficient. BUT - the industry states that these are non-load bearing and for good reason. Not everyone building a hearth is gonna know to engineer it for rigidity. I would bet that many/most would simply use a bottom and top plate (called runner in the industry) and slap these in at 16" on center, slide it into the corner and finish the top. That could be a disaster waiting to happen. By going to the heavier gauge, you could minimize that issue. And with as small of an area, and the few studs that are being consumed, the cost will only be a few bucks to go to the heavier ga. material.

There are lots of ways to engineer strength, heck you could go to 4" on center (and use spazer bars) if you wanted to. But I feel the need to put this info out there for the general masses. A standard build (16" OC) using the light gauge studs is not recommended.

 

[Dakotas Dad]

I always wondered if people who work with this stuff called it a top and bottom plate.. a "runner" rather than a plate..

I think the biggest issue is finding a local source for the heavier studs.. most are kind of forced to go with whatever the big box store has, for various reasons. We ran into that a couple times just on our little hearth build. Either minimum order size, or "we only work with contractors", to flat out availability of any other source.. We had to drive 3 counties over to get ONE bale of rock wool.. and near as I could find that is the only distributor in our end of the state. I happened to call on a day when a contractor had ordered/received a minimum order of 40 bales, and only needed 37, the distributor's secretary was in a good mood, and gave me his number..

You don't even want to know about that custom tile.. and why the field is 2 wide 3 high.. instead of 3 and 4.. 4 more tiles would have cost $375. Because you can only order "full runs".. and we needed 4 more tiles than a single run.

 

[Jags]

I suppose availability could be an issue, but we carry the heavier gauge as standard stuff and we have two competitors that also do. Could be a regional thing I guess. And we sell (as well as our competitors) to the general public along with contractors.
Maybe you just need friendlier neighborhood drywall supply houses.

 

[Jags]

I always wondered if people who work with this stuff called it a top and bottom plate.. a "runner" rather than a plate..

"Track" is another common term you will hear contractors use.

 

[firefighterjake]

DD - I do not doubt your success, but I can also stand on an empty beer can without crushing it (I weigh 235 pounds).

I needed the exercises so I walked out to my steel racks. Here is the reality of a 24/25 ga stud:
View attachment 131356
I could have crushed this like a beer can.

Your hands look much different than I imagined.

 

[Highbeam]

I used the lightweight steel studs, topped and sided with durock (2 layers on top, one on sides), and then ceramic tile. I had to do it this way to meet the R-value requirements of my hearthstone since micore was not available and plywood on top of the studs would have been combustible so not allowed.

Yes, you must use thinset between the durock layers. You attach the bottom durock to the studs. Mud and tape the seams. It feels a little flexy when you walk on it. The second layer of durock with thinset between and screwed down to the studs makes a huge improvement in rigidity.

The studs look thin and weak but in Jags' photo the side flange is not being held, nothing is being crushed, just bent. Had the side flanges been restrained he could have never crushed that with his hand. My heavy old hearthstone full of wood and with a couple people standing next to it were just fine up there on the hearth.

I would have rather used wood for ease of construction.

 

[plumberman57]

I used 20 gauge studs from Menards on 12" centers then covered with sheet metal and 2 layers of durock. There was no problem with the studs supporting the weight of an Englander NC-30, but there was deflection of the durock between the studs, so i covered with an additional layer of durock and solved the problem.

 

[Highbeam]

I used 20 gauge studs from Menards on 12" centers then covered with sheet metal and 2 layers of durock. There was no problem with the studs supporting the weight of an Englander NC-30, but there was deflection of the durock between the studs, so i covered with an additional layer of durock and solved the problem.

Agreed, that second layer makes all the difference.