Little help with my build.

[Rickb]

I am finally to a point where we have a mason coming to do the stone work.

I did the hearth out of 2x6 framing on 12 inch centers skinned with 3/4" plywood then 1/2" cement board thinset over it.

The mason has concerns that the hearth will not hold up the weight of the fireplace facade we want. The facade is going to be over 2000 lbs. The mason wants to cut out the area of the hearth that will be under the legs and build it up from the floor with masonry.

What do you guys think? This is a very poor rendition of what we are doing.

 

[Rickb]

oh and here is the stone we are using....

facade stone and mantle and inside.

 

[fossil]

I've never argued with a mason, nor have I ever had any masonry fail.

 

[Rickb]

well I had 5 different masons when we bid it out. 2 said we should cut out the hearth 3 said it should be fine. I am not really arguing the point. More just wondering what is the load baring strength for 3/4 plywood on 12 inch center supports?

 

[Ram 1500 with an axe...]

Idk listen to them but go wider on the facade, do it right the first time...

 

[begreen]

The hearth is not holding up the weight of the facade. The walls are. If you want to reduce weight, go for thinner stone. Visually it will look the same.

 

[My Oslo heats my home]

I can understand the masons concerns, considering he owns the work once he finishes it. I believe the way you framed the hearth will handle the weight. Although if it were me I would have had the mason pour a small slab or I would have poured one myself considering your on a concrete floor to begin with.
I like your choice of materials! Post pics as you go along

 

[Rickb]

Well I went ahead and got concrete today and the mason is here right now. He said he will cut out the spot in the hearth and do the concrete tonight before they leave at no added cost so its no big deal. I really just wondered more why some wanted it done and others didnt.

In hind sight I wish I would have done it the way I was going to do originally, which was form it out in 2x6 then pour concrete. Thought it would be to hard since I have never done anything with concrete.

 

[Hogwildz]

Make sure the plywood has enough clearance for the specs of the burner your using. Just because you have steel studs behind and cement board on top of the plywood, it is still a combustible. Make sure you retain proper clearances per the manual specs for your burner.

 

[Rickb]

Its plywood with 1/2" cement board then 2.5 inch indiana limestone slab on top of that for the hearth. Inside the fireplace area its plywood + cement board, then I added 2 inches of cement then thin brick and mortar on that.(This was done to help raise the thin brick up to close to the level of the limestone. Plus I wanted the added protection of the cement if the stove failed for any reason.) The hearth will be 28 inches wide outside of the firebox area. So looking at the BK website if I read the manual correct for the sirocco "Floor protection may be any non-combustible material or Listed Floor Protector".

I assume this should be overkill for what the stove requires?

 

[Rickb]

Ok stove is here! We decided to do the burn in outside so it didn't smell up the house.






And the mason is moving along on the stone work, should be done tomorrow!

 

[ScotO]

That's shaping up to be a very nice install! As for the extra support pouring concrete like you did, nothing wrong with a little overkill.....I didn't get that name for nothing!

 

[Rickb]

Wish the mantle was a little bigger but we kinda ran out of time getting it all figured out. It looks a little big different in person.

 

[Ram 1500 with an axe...]

Looking great, I love your plan....

 

[ScotO]

Wish the mantle was a little bigger but we kinda ran out of time getting it all figured out. It looks a little big different in person.

I think it will be fine. I can't wait to see it with the stove installed......
you'll enjoy that puppy come October....

 

[Hogwildz]

Its plywood with 1/2" cement board then 2.5 inch indiana limestone slab on top of that for the hearth. Inside the fireplace area its plywood + cement board, then I added 2 inches of cement then thin brick and mortar on that.(This was done to help raise the thin brick up to close to the level of the limestone. Plus I wanted the added protection of the cement if the stove failed for any reason.) The hearth will be 28 inches wide outside of the firebox area. So looking at the BK website if I read the manual correct for the sirocco "Floor protection may be any non-combustible material or Listed Floor Protector".

I assume this should be overkill for what the stove requires?

According to the BK Sirroco manual, the minimum side clearance measurement is 10-3/4".
Minimum measurement from the back furthermost box is 6". The rest you can read in your manual.
The stone,cement & cement board if I remember correctly are not included in the clearance to combustibles as they are not combustible.

The problem I see here, is you are installing into an alcove that you built, and the alcove clearances called for are different.
From the manual: "Min. Alcove minimum width 48”, maximum depth 48”, minimum height 72”
Maybe just deceiving in the photos, but does not look like you have any of those clearances.
The plywood may in fact be an issue. The stone & cement board do not reduce clearance requirements, they simply are not included.
What are the dimensions of your alcove? And how close if the plywood itself in measurement from the stove back, sides, top and the pipe also?
Keep in mind the clearances are for your stove with a fan kit, or rear heat shield with double wall pipe.
I still think you may have serious issues due to the alcove requirements, and that plywood is concerning.
Not trying to rain on your parade, just safety first is all.
Do not want to read about you or your home in the papers.

 

[Rickb]

Hoping to have the stove siting in place on plywood tomorrow evening. OAK will be here Tuesday, and carpet is being installed Wednesday.

After the break in fires we turned her up a bit. I put in around 8 - 2x4's that were cut to around 8 inches and it burned on wide open for 6 hours and was still hot. Just put it back in the garage 10 minutes ago.

 

[Rickb]

According to the BK Sirroco manual, the minimum side clearance measurement is 10-3/4".
Minimum measurement from the back furthermost box is 6". The rest you can read in your manual.
The stone,cement & cement board if I remember correctly are not included in the clearance to combustibles as they are not combustible.

The problem I see here, is you are installing into an alcove that you built, and the alcove clearances called for are different.
From the manual: "Min. Alcove minimum width 48”, maximum depth 48”, minimum height 72”
Maybe just deceiving in the photos, but does not look like you have any of those clearances.
The plywood may in fact be an issue. The stone & cement board do not reduce clearance requirements, they simply are not included.
What are the dimensions of your alcove? And how close if the plywood itself in measurement from the stove back, sides, top and the pipe also?
Keep in mind the clearances are for your stove with a fan kit, or rear heat shield with double wall pipe.
I still think you may have serious issues die to the alcove requirements, and that plywood is concerning.

There is only plywood on the bottom. The sides are concrete, then steel studs, then cement board, then brick. No combustibles on sides or up. The alcove picture is deceiving. If you look under it its 7 foot straight up before you hit the ceiling box.

The closest com bustle to the side is 5 foot and to the top is 7 foot with a fire stop. Will try to get a pic tomorrow.

 

[Hogwildz]

Ah ok, I misread then. So the only place you have the plywood in on the bottom at the hearth? My mistake.
Not sure how they would interpret the alcove minimum measurements? Not sure if that is to combustibles, or required air space?
They don't give any details as to what they mean by the measurements. But if your all stone & steel studs, top & sides, you should be ok.

 

[Rickb]

couple progression pics....

 

[Hogwildz]

How thin is the face stone? And if I may ask, what brand it it? Do they make ledge stone looking product that thin?

 

[Rickb]

Ah ok, I misread then. So the only place you have the plywood in on the bottom at the hearth? My mistake.
Not sure how they would interpret the alcove minimum measurements? Not sure if that is to combustibles, or required air space?
They don't give any details as to what they mean by the measurements. But if your all stone & steel studs, top & sides, you should be ok.

Yes its all stone and steal and cement on the sides and above the stove. I also have the back shield kit and fan kit. I will be watching the temps above it the first couple burns just to make sure there is no heat issues, tho I don't know how there could be any.

 

[Rickb]

How thin is the face stone? And if I may ask, what brand it it? Do they make ledge stone looking product that thin?

The main fireplace face stone is 4 inches thick. and the left side is the same stone thin cut to 2 inches. The stone type is mixed Aux Vasse.(mixed just means some tan and some blue.) The mantel and hearth is Indiana limestone.

 

[Hogwildz]

Oh, I thought the stone was veneer? If it is, that is some thick veneer.
How did you anchor the mantle pc?

 

[Rickb]

The mantle is sitting on top of the face and has the stone on top sitting on it. Over all ita about 1500 pounds of stone and 500 pounds of mortar on the main fire place. Then the mantle is like 120 pounts and the hearth will be around 600 pounds with mortar.