Wood Fireplace - I am going to ask you fine peeps for some assistance

[jayoungny]

Hi

My wood burning fireplace is in need of work. There is nothing wrong with the prefab firebox, nor the chimney. The sidewalls are too close to the firebox (min. clearance not met), the hearth is too small, and there is no caulking. The last part is easy - I think.

Here is a pic of what it looked like before I pulled off the sidewalls. The manual calls for 21.5" sidewall clearance (for combustible material), and as you can see, the walls - which are painted wood - are literally adjacent to the firebox.



The original idea was to take off the sidewalls, and move them outward to spec, having no idea what I was going to do with the space in between, and not knowing what was going to be behind those side walls. After thinking on it, I decided to simply ditch the sidewalls and go up with stone. So, I take off the sidewalls, and the trim, and I see nothing but drywall.



My first thought was to just leave it, and install the stone onto the drywall, but then I am thinking, 1) even with the stone, the drywall is maybe not supposed to be that close to the fbox (sides and top), and 2) can you really install stone directly onto drywall? Prolly not.

I then took off some drywall that was next to the fbox:



On the l side there are three studs. Not sure about the r side yet (prolly the same). The first stud has an attachment to the top of the fbox, the middle stud has an attachment to the bottom of the fbox (not sure why the box is att to two diff studs), and I assume the third stud (not really visible in the pic) is a framing stud. But not sure just yet.

What I am thinking now, is I have to rip off enough of the drywall, to 1) not have any too close to the fbox, and 2) expose some studs, so that I have something to screw backerboard into. Then mortar and then stone. Does this sound like a plan, or is there a better way to approach this?

Also, do I replace the hearth before I do the b.board and stone, or after, or does it not matter?

Thank you!

 

[blades]

IMOP that is a gas( Natural or Propane unit) not really meant for soild fuel, by the construction around it. What happen to a friend with something similar was the supporting framing after many years became charred and one day that framing started burning. He was lucky? as he just happened to lean against the stone facade and it felt quite hot some distance away from the unit. Called the FD got everyone out of house. By the time the FD arrived ( maybe 10-15 min.) things had gotten quite exciting. there was damage to both the first and second floor walls although it had not gotten to the roof. There were/are some fireplace inserts designed as zero clearance using soild fuel with a triple wall box and flue system. the flue system was made to pull cold air down and circulate it in & around the outer box , exhaust went up the middle. Right now I can't think of the name. all though the brand name is still around but not the same co. Had a wall mounted unit same design circa 1960. Couldn't get flue repair parts anymore so tore it out and replaced with conventional free standing stove.

 

[begreen]

What is the make and model of the fireplace? There should be a nametag on it, typically in the door channel.

 

[jayoungny]

Thank you for the replies

IMOP that is a gas( Natural or Propane unit) not really meant for soild fuel,

This is a wood burning fireplace.

What is the make and model of the fireplace? There should be a nametag on it, typically in the door channel.

Yes, there is a tag. Have att a pic. It's a Majestic RC36, manu'd in 1984(ish)

 

[EbS-P]

Read up on install specs. I didn’t look to close but it appears that it was installed without adhering to distance to combustibles. I’m not sure I’d go through the fix and leave a nearly 40 year old unit in place.

https://manualzz.com/doc/10671973/majestic-r36-rc36

 

[begreen]

Thanks for posting that link. Now Jay has dimensions and clearance specs to verify.

 

[jayoungny]

Hi

I have that manual.

 

[begreen]

If you have verified that the clearances have been honored for the framing, then yes, your plan is correct. I am not sure the hearth needs replacing. What is the distance from the fireplace glass to the front edge of the hearth? If it is 16" or more then it is ok.

 

[jayoungny]

If you have verified that the clearances have been honored for the framing,

Well, I have, - sort of. If you have some insight, please feel free.

The manual says that combustible sidewalls can be no closer than 21.5" w/o use of a heatshield. I take that to mean protruding sidewalls. It doesn't specify anything about the framing, tho. So, I asked the manu about the framing, saying this:

The firebox is screwed into wooden studs, which are just inches from the firebox. The fact that the studs are recessed, and not in front nor flush with the front of the firebox - but instead behind it... is that what makes this ok?

And they responded with this:

We recommend working with your local dealer to determine where to install combustibles vs non-combustibles on or around your fireplace.

My local dealer says that's fine; I was there a few days ago. That's why I said "sort of" earlier. I want to say that it's ok based on what I was told. But I was also told by someone in my bldgs dept that those protruding sidewalls would still not be ok even if they were covered in cement backerboard and stone. And I asked why, when the stone is non-combustible, and the answer I got was "heat transfer". Which makes sense now that I think about it. And that causes me to still be iffy on the framing, even tho the dealer said it's ok.

The hearth right now protrudes 3.5" on either side, and 18" outward. The manual says this:

the hearth extension needs to extend 8" on the sides and the front needs to extend 22"

So, I need to replace the hearth.

The time is appreciated

 

[begreen]

A side wall is different from trim. I suspect the original trim was ok, but again, the manual and the mfg. have the final say.

The hearth side measurement is usually from the door opening, not the entire fireplace chassis. If all it needs is a side extension then it might be easier to inlay something non-combustible and attractive. That said I see that the chart requires 22" hearth for this fireplace, so it is also 4" shy in depth. My error in not bringing up the docs. A 4" border trim could be attractively done as an option to total replacement.



As suggested, be sure this 40 yr old fireplace is worth encapsulating behind stone veneer. Has it been thoroughly checked over by a certified sweep?

 

[stoveliker]

Regarding clearance to combustibles (the "heat transfer" remark), the explanation is this: if you have a clearance requirement of xx inches to combustibles, it does not matter whether there is air in that xx inches or stone. I.e. a clearance of 10 inches cannot have studs at 6" with a 2" of stone in front of it.

The reason is that non-combustibles do not have a set heat transfer rate and there is no guarantee that the studs would not get too hot. Yes, for some materials it will be fine, but for many others it will not. Rather than specify what you can put in between so that the distance to the studs doesn't matter, the easiest (and thus safest because easier compliance) is "no combustibles within that range regardless of what else is in that range".

 

[jayoungny]

A side wall is different from trim

Right - but I was referring to side walls vs the framing studs that the fbox is affixed to.

Has it been thoroughly checked over by a certified sweep?

Yes and no. I had a chimney co. come in to clean the chimney, and when the guy walked in, I heard, "uhh, we have a problem". That's how I found out that the fireplace did not meet the min. requirements. I have not had anyone back since, but after reading your post, I am thinking it might be a good idea to have a chimney co. come in and just look at the framing (pic 3 in my op).

 

[blades]

Majestic was the name of unit I had and my friends. At 40+ years of age likely best to start from scratch.

 

[jayoungny]

Update:

I had a chimney sweep here, AND I walked into the office of another, with pic #3 and the manual. Both said what I have is fine (save for the insulation around the firebox, which I have removed). The guy that was here said, "it may seem crazy, to have wood that close to the insert, but that's how it's done". They both told me (diff words, of course) as long as there is air inbetween the insert and the studs (which there is) it's fine; they said that with those gaps and the style of chimney, those units stay pretty cool. I asked the guy who was here if there is any reason to replace the box, and/or start from scratch, and he said he saw no reason to do so.

So off I go to do the work.... will post back when done.

 

[Lennox65]

Well, I have, - sort of. If you have some insight, please feel free.

The manual says that combustible sidewalls can be no closer than 21.5" w/o use of a heatshield. I take that to mean protruding sidewalls. It doesn't specify anything about the framing, tho. So, I asked the manu about the framing, saying this:

The firebox is screwed into wooden studs, which are just inches from the firebox. The fact that the studs are recessed, and not in front nor flush with the front of the firebox - but instead behind it... is that what makes this ok?

And they responded with this:

We recommend working with your local dealer to determine where to install combustibles vs non-combustibles on or around your fireplace.

My local dealer says that's fine; I was there a few days ago. That's why I said "sort of" earlier. I want to say that it's ok based on what I was told. But I was also told by someone in my bldgs dept that those protruding sidewalls would still not be ok even if they were covered in cement backerboard and stone. And I asked why, when the stone is non-combustible, and the answer I got was "heat transfer". Which makes sense now that I think about it. And that causes me to still be iffy on the framing, even tho the dealer said it's ok.

The hearth right now protrudes 3.5" on either side, and 18" outward. The manual says this:

the hearth extension needs to extend 8" on the sides and the front needs to extend 22"

So, I need to replace the hearth.

The time is appreciated

One of the most neglected details with factory built wood burning fireplaces is the hearth.
On page 11 of your manual it details exactly what is required to attain the proper protection.
What most people miss, or conveniently ignore, is the REQUIREMENT of additional material between the finished hearth and the combustible floor below it.
In your case it is calling for a Product that is specific to the manufacturer. That may or may not still be available but you can find something equivalent as long as it has the same k factor/R value. Micor is one brand name that is currently available.
https://www.hudsonvalleychimney.com...Pyrolysis occurs when wood is,at least 400° F).