new insert install qestions

[Benchwrench]

Hey Guy,

First of all a big thanks to all you guys who helped me choose the best way to go with what I have to work with.

Being very limited to a height restriction, I have decided that installing an insert would fit my arched FP without having to cut any brick on the arch.

Now it's time to prep the masonry opening for an insert. I have a few questions in this regard I was hoping you guys could also shed some light upon...

Here are some pictures of my FP.

The hearth is going to be extended by 8" by laying another course 15" high out in the room. This satisfies the 16" ember protection.

Do I need to repair or install new sides and back facade in the firebox area?
I noticed there are defects such as cracks splits and chunks out of the fake brick, here are a few pictures...
the picture with the hot spot from a flashlight highlights the crack that travels down to the floor of which is also cracked up.

The floor also has cracks in it.
I will be covering the floor with a course of brick to level out hearth and firebox for the insert to slide into.
Can I use any kind of brick for the floor? and does it have to be "mortared-in" or can I just lay them in by themselves?

Here are a couple of the damper and lintel just above it behind the brick facade.

The damper is 33" wide and the PF itself is 40" wide.

I was planning on installing 6" Duravent product called "Ventinox" it is designed with a continous weld and is a 316-Ti. liner. Plans are to put a blanket of 1/2" foil wrap of approx. 25 ft. all the way up to the cap.

Do I need (or should I) install a metal anchor plate (above the insert at the damper area) or bottom plate for an insert?

What am I missing besides a sweep?

 

[karl]

The official answer is: That depends on the type of insert you install. A zero clearance insert will be fine because it has no clearance requirements.

The long answer is: Probably not. You have some cracks but that fireplace is not in bad shape. You could clean out the cracks and grout them again and be perfectly fine or leave them as is and probably be fine. Since you're going to add brick for the ember protection, you'll have motar mixed up, so go ahead and clean the cracks out and fill them.

My big question is what do you mean by "fake brick"? I don't see anything in the pics that doesn't look like real brick. If you have some "fake" stuff in there that is flammable then you're going to have to address it.

As for the floor, if it's one level of brick and strictly to level things out, you don't need to mortar it. I qualify that statement by adding: If you put this one level of brick in so the insert rests solidly on it without it or any brick 'teeter tottering". Since the floor is cracked, I would look under neath it so make sure it's capable of holding the weight of the insert and brick. It probably is.

Unless you have some sort of forced perspective going on in your pics making the damper hole look smaller than what it is, then good luck fishing a 6 inch liner through there. You're going to invent some new dirty words. If you have to cut it. Take a little bit of time and don't do a hack job on it.

 

[Benchwrench]

...My big question is what do you mean by "fake brick"?...

I call it fake brick, that's the interior firebrick lining that's comes in sheets and applied to the inside of a FP, basically what's cracked in the pictures.

 

[Benchwrench]

...Unless you have some sort of forced perspective going on in your pics making the damper hole look smaller than what it is, then good luck fishing a 6 inch liner through there. You're going to invent some new dirty words. If you have to cut it. Take a little bit of time and don't do a hack job on it.

I fully understand...
I was planning on doing a demo on the damper and most likely the smoke shelf so I can get a 6" liner in there with out having to ovalize it.
In other words cut the damper in two and permanently modify that area by taking out one course of brick from the smoke shelf.
( I think that's what needs to be done. )

I've never modified a chimney damper before but I was planning on using a cutting blade on my angle grinder and cutting a U shape out of it so the liner will fit that shape and then remove whatever brick that's behind there.

 

[KSgrown]

I could be misunderstanding what you're trying to accomplish here, but it seems like a lot of extra work and money for little gain.
Extending the hearth by a course seems like overkill. You could do a short section of ceramic tile to get the clearance required, but maybe a hearth extension is really what you want and I can't argue with "wants" vs. "needs".
I agree that nothing in your pictures indicates fake brick and personally, I wouldn't be worried about some cracks in the existing brick wall or floor. The purpose of that masonry fireplace was to house a fire and it appears like it has done that with some success. It will be exposed to much less direct heat during the use of an insert than it did with an open fire. With that being said, during my install, I put fiberglass batt insulation along my rear firebox wall and covered it with sheet metal to minimize heat loss through the rear of the firebox. Same with the "metal anchor plate" that you refer to, it will help minimize heat lost up the chimney cavity but probably isn't required. You can search on here for "block off plate" and find many fine examples of how people have done this and reasons why it's a good idea. It will help to isolate your chimney cavity from your living space, reduce the "chimney affect" and like I said, help with heat loss.
As for adding a course over the firebox floor, again, I don't quite understand the point. I would think that the insert will slide in just fine how it is. But again, you are the one that has the best understanding of your situation and if a course of brick is required, I do not feel that it would need to be mortared.
I also agree that in your picture, the damper looks smaller than the 7" that you will need to pass the insulated flue through. My damper looked very similar to yours and I had to cut that tab off with a sawzall that is at the bottom center of the damper opening. Even then, I had to have my 6" flue ovalized to 4.5"x7.4†in order for it to fit properly with the 1/2" rock wool blanket insulation. Luckily, the place I bought it did that for me and shipped it already ovalized. But it ended up working great and I'm sure yours will too, just plan ahead!

I have a lot of pictures of my install if you are interested in what it looked like, just let me know.
You've found a great resource for finding information on this topic, just keep asking your questions and someone will know the right answer!
Good luck,
Doug

 

[KSgrown]

...Unless you have some sort of forced perspective going on in your pics making the damper hole look smaller than what it is, then good luck fishing a 6 inch liner through there. You're going to invent some new dirty words. If you have to cut it. Take a little bit of time and don't do a hack job on it.

I fully understand...
I was planning on doing a demo on the damper and most likely the smoke shelf so I can get a 6" liner in there with out having to ovalize it.
In other words cut the damper in two and permanently modify that area by taking out one course of brick from the smoke shelf.
( I think that's what needs to be done. )

I've never modified a chimney damper before but I was planning on using a cutting blade on my angle grinder and cutting a U shape out of it so the liner will fit that shape and then remove whatever brick that's behind there.

Sorry, you posted this while I was writing my opinions... it sounds like you have a plan in place so you don't have to ovalize. Again, good luck and we all like pictures of your progress!

 

[mhrischuk]

I assume you want to raise the insert so the shroud covers the top of the arch? Some wood inserts have optional larger shrouds by special order.

I used a cutting wheel on a grinder. It really worked well.

 

[webby3650]

That's firebox is pretty interesting, don't think I have seen pre-fab panels in a masonry fireplace before. Seems like you are on the right track, cut the damper as needed, don't worry about the cracks in the refractory , they will be fine. I don't think you will need to extend the brick hearth, tile on the floor would be fine. You can make a sheet metal "block off plate" if you just want to, it is better but not necessary, either way, you will get a tremendous amount of heat out of this insert compared to an open fireplace.

 

[Huskyforlife]

Don't extend the hearth with another course of bricks, that's way too much work. Make a tile pad that will sit in front of it instead. You can make one for about $40 in materials from Home Depot. Bonus is you can make it just a pad and so it is removable in the summer when you are not using the stove.

 

[Benchwrench]

... it seems like a lot of extra work and money for little gain.
Extending the hearth by a course seems like overkill. You could do a short section of ceramic tile to get the clearance required....

Pros:
If I do a hearth extension I gain a larger footprint for firewood on standby next to the stove.
without tripping over a 1" high ember protection extension.
removing this pad at the end of the season and finding a safe place for it until the next season.
it might be more into proportion with the insert, hard to tell right now.

Cons to extending the brick hearth:
price of hiring a professional brick mason
getting a spot on match of the existing brick so it doesn't look like it was "added on"
it permanently will remove 9" of floor space some 7' wide as well as cutting out a solid oak floor.
without having the insert in place I can't visualize the depth as well as I'd like.

It might be best to try the ember/ pad extension first and go from there.
Speaking of... I would like a use a natural stone appearance such as Slate. What type of stiff underlayment are you guys recommending to gain the required R value?
I'd need something stiff, kind of like plywood so it's durable when needing to pick it up off the floor after the burning season to put it in storage.
Do you guys know of a link or thread as to how to make one of these floor protectors?

... during my install, I put fiberglass batt insulation along my rear firebox wall and covered it with sheet metal to minimize heat loss through the rear of the firebox...

Does that mean the rear of the appliance (the sides as well) radiate enough heat that there is a need for a rear "firewall liner"?
I'll have to see your pictures how you attached it to the refactory "brick".

...You can search on here for "block off plate" and find many fine examples of how people have done this and reasons why it's a good idea...

Definitely will be searching the archives. I also want to consider packing rock wool above the bottom plate (if I install one) or at least that area around the bottom of the insert as well as around the top of the liner under the top plate. I have to research just how much to pack as well as knowing if I have to leave it "fluffy" and try not to compress it too much

...As for adding a course over the firebox floor, again, I don't quite understand the point...

I know it's hard to tell in the pictures but my hearth is higher than the firebox area, the firebox sits about 3" lower than the brick hearth or by about the thickness of a brick.

...I have a lot of pictures of my install if you are interested in what it looked like, just let me know...

I always gleen ideas from what you guys share, the search feature will always come in handy, I'll send you a PM.

...You've found a great resource for finding information on this topic, just keep asking your questions and someone will know the right answer! Good luck, Doug

You know it and thanks very much for your reply

I am very excited

about getting an insert installed very soon, I need to get busy with the demo.
Bench

 

[Benchwrench]

That's firebox is pretty interesting, don't think I have seen pre-fab panels in a masonry fireplace before. Seems like you are on the right track, cut the damper as needed, don't worry about the cracks in the refractory , they will be fine. I don't think you will need to extend the brick hearth, tile on the floor would be fine. You can make a sheet metal "block off plate" if you just want to, it is better but not necessary, either way, you will get a tremendous amount of heat out of this insert compared to an open fireplace.

Based on the minimum ember protection requirement, all I need is 8" out on the floor, yea. That's why I was considering the brick hearth extension.
I notice you guys normally would install a bottom plate for a wood stove/hearth mount application but not for an insert.
Since the insert is self contained, a bottom plate just wouldn't be necessary.
I'm still curious about needing a rear reflector plate though, this place needs all the btu's it can get.

 

[Benchwrench]

I assume you want to raise the insert so the shroud covers the top of the arch?...

the hearth is higher than the firebox. I need to level everything out. Great camera pictures by the way, thanks.
I also have a sawsall if the cut off wheel doesn't fly.

 

[KSgrown]

The hearth extension topic is completely up to you on how you want to handle that. Don't tell anyone, but we went through last winter without having the "required" clearance and tried to be careful. But, sometimes you are being careful and accidents still happen, so I would recommend the suggested clearances and we are now planning to do ceramic or slate tile in front of our hearth.

Do you guys know of a link or thread as to how to make one of these floor protectors?

I would also be interested in knowing how to make a temporary floor protector.

Does that mean the rear of the appliance (the sides as well) radiate enough heat that there is a need for a rear "firewall liner"?
I'll have to see your pictures how you attached it to the refactory "brick".

I don't know that they do radiate enough heat to make much of a difference. My chimney's rear wall is on the exterior and faces North, so it has a large potential to suck heat out of the original firebox area. As a HVAC designer, I work to minimize and deal with heat loss/gain everyday, so this became something that I wanted to address. I doubt to many people do this, I just felt like it was for good measure. I would probably never be able to tell a noticeable difference, it was just "one of those things" that I got stuck in my head that I should do and it was easy enough that I went ahead and insulated it and hoped the sheet metal would act to reflect some radiant heat. I didn't do the entire firebox liner, just the rear wall. Honestly, I felt like the block off plate was more beneficial than insulating the rear wall. The block off plate keeps the heat from your insert from rising up into the unused part chimney, which is now dead air space. Sealing at the top with the cap and at the bottom with the block off plate truly isolates the dead air from absorbing BTUs from your insert. Using a block-off plate will be a more efficient installation.

This is what I made mine off of, it worked well:
https://www.hearth.com/econtent/index.php/articles/making_a_block_off_plate/

Also a good article about insert installation and some pros to do a block-off plate. This also speaks to hearth extensions, oval vs round, etc...
https://www.hearth.com/econtent/index.php/articles/install_insert

I attached all the sheet metal with Tapcon concrete screws.

I know it's hard to tell in the pictures but my hearth is higher than the firebox area, the firebox sits about 3" lower than the brick hearth or by about the thickness of a brick.

Ok, I understand why you would want to raise that up. 3" is more substantial than I had assumed by the picture.

 

[KSgrown]

If you want more opinions about insulating around the firebox, here is a conversation about it with a picture of how one person did it:
https://www.hearth.com/econtent/index.php/forums/viewthread/59864/P0/

Also, this person has a good walk through of his firebox insulation procedure and block off plate:
https://www.hearth.com/econtent/index.php/forums/viewthread/27409/

 

[stejus]

Benchwrench - read that wording about 16" clearance. I didn't have the 16" clearance, but I did not have to extend the hearth because it is raised. Here's the wording in my manual. Your's may be similar or different. Check out my install pic's to see what I did for floor protection.

Thermal floor protection not required if unit is
raised 3.5" min. measured from bottom of stove. At
this point the standard ember floor protection will
be required. It will need to be a non-combustible
material that covers 16" (406 mm) to the front
of the unit (in Canada 18" (450 mm) and 8" (200
mm) to the sides.
All floor protection must be non-combustible (i.e.,
metals, brick, stone, mineral fiber boards, etc.) Any
organic materials (i.e. plastics, wood paper products,
etc.) are combustible and must not be used.
The fl oor protection specifi ed includes some form
of thermal designation such as R-value (thermal
resistance) or k-factor (thermal conductivity).

 

[krex1010]

Im in no way an expert on installing inserts, but just looking at the pics it seems like the fireplace is in pretty good shape. Maybe you might want to consider having a certified sweep come out and clean and inspect your chimney and fireplace. It might save you a lot of work and money. You may find out that you don't have to make as many changes as you think. Just my two cents.

 

[Huskyforlife]

The hearth pad is easy. You will need some tiles (I used three 18" ones I had left over from a project around the house). Once you have those, then make a base of plywood and then durarock. Tile over the durarock. Trim around the whole pad and then grout. Finally, put some of these fabric sticky pieces they make for furniture under the pad as feet. Presto, you have your removable pad.

 

[kingquad]

Morso sells thick pieces of tempered glass to use as hearth pads and ember protection for inserts. I'm willing to bet a local glass places could cut you one to your dimensions with a nice beveled edge for a decent price. Would save you some time. I did tile in front of my hearth, but I'm always tearing up and rebuilding parts of the house. It drives my wife insane.

 

[Benchwrench]

Benchwrench - read that wording about 16" clearance. I didn't have the 16" clearance, but I did not have to extend the hearth because it is raised. Here's the wording in my manual. Your's may be similar or different. Check out my install pic's to see what I did for floor protection.

Thermal floor protection not required if unit is
raised 3.5" min. measured from bottom of stove. At
this point the standard ember floor protection will
be required. It will need to be a non-combustible
material that covers 16" (406 mm) to the front
of the unit (in Canada 18" (450 mm) and 8" (200
mm) to the sides.
All floor protection must be non-combustible (i.e.,
metals, brick, stone, mineral fiber boards, etc.) Any
organic materials (i.e. plastics, wood paper products,
etc.) are combustible and must not be used.
The fl oor protection specifi ed includes some form
of thermal designation such as R-value (thermal
resistance) or k-factor (thermal conductivity).

I like that aspect of your manual but my manual is worded "ember protection" even though I believe to meet the "thermal" needs of the flooring (which is an oak floor)

I did read a little deeper though and found that the measurement is taken from the door and not the appliance edge AND they don't give a rip how high the hearth is from the floor. It's a lateral distance thing.

 

[Benchwrench]

Im in no way an expert on installing inserts, but just looking at the pics it seems like the fireplace is in pretty good shape. Maybe you might want to consider having a certified sweep come out and clean and inspect your chimney and fireplace. It might save you a lot of work and money. You may find out that you don't have to make as many changes as you think. Just my two cents.

I have a sweep planned next week, I also asked if he has time to help me install my new insulated liner while we're up there, he said yes, does it all the time.