Framing out for Wood Insert

[JayLii]

Hey everyone.

I am looking for some feedback on my installation of a Supreme Volcano Plus fireplace insert. It ships with their new Circulating Chamber (see attachment) which is essentially a metal surround you are meant to fasten into your masonry.

What I am hoping to do is build out 12" from my wall to accommodate built bookshelves on either side. This of course brings the insert that far away from my existing fireplace and chimney. I will probably have to take a couple bricks out to allow the flex liner to run on a desired angle up into the exterior chimney.

I will still be installing a fixing plate to seal the chimney, but my concern lies around the part of the firebox that will not be surrounded by brick. My first thought is to frame out a new wall 12" from the old one and the existing fireplace opening using metal studs around the fire area and fire-rated cement board, fasten the new circulating chamber to the metal studs.

Do I need to close in the area above (horizontal) the circulating chamber/insert with a couple layers of cement board and run that right into the brick? I could leave a gap for some roxul in there too. I don't want a lot of heat being transferred above the chamber because there will be a mantel going up and above that most likely a TV. (with clearances in mind) The volcano plus does have a couple blowers in it as well.

I haven't come across anyone installing a wood burning insert in anything but completely setback in a masonry fireplace. Is what I want to do even safe with this wood insert?

Manual is here if you are interested:
http://www.supremem.com/docs/Volcano Plus manual (english) Modified.pdf

Thanks in advance for your help and thoughts!
James

 

[begreen]

The constraining factor for the insert is the side clearances. According to the manual this appears to be 9" for side combustibles <2". For >2" this becomes 10.5". Wood framing behind cement board does not qualify for any clearance reduction. I'd keep the insert in the fireplace and start the side book cases 11-12" away from the insert.

 

[JayLii]

Hey thanks for the reply @begreen.

Yes the side clearances will determine the width of the fireplace build out. I really don't want the fireplace to sit in behind the bookshelves I think that looks weird.

If I use steel framing I think it should be fine, no?

So what you're saying is that there isn't any way to lower the the clearance distances by use of fire resistant materials?

The fireplace insert will be showing up this week hopefully so I'll be able to post some pictures and have a clearer post beyond the introduction.

James

 

[begreen]

There is no tested clearance reduction guidance for this particular application that I know of. As far as I can see the circulating chamber is meant only to be used in the fireplace. Might be able to fake it with metal studded and cement board cladding, but that would take getting written permission from Supreme and the local inspector, which I would not expect because it's untested, but give them a call. The clearance to the nearest combustible would still be 10.5" Given the venting hassle it may not be worth it.

It's not uncommon for the side book cases or cabinetry to project out past the fireplace. There are lots of examples.

 

[JayLii]

There is no tested clearance reduction guidance for this particular application that I know of. As far as I can see the circulating chamber is meant only to be used in the fireplace. Might be able to fake it with metal studded and cement board cladding, but that would take getting written permission from Supreme and the local inspector, which I would not expect because it's untested, but give them a call. The clearance to the nearest combustible would still be 10.5" Given the venting hassle it may not be worth it.

It's not uncommon for the side book cases or cabinetry to project out past the fireplace. There are lots of examples.

View attachment 197110 View attachment 197111 View attachment 197112 View attachment 197113

I do like the look of some of these. Thanks for sharing them. I have adjusted my plans to use more of this style. However, I just measured the opening and the insert is still going to protrude about 8" from the current brick opening even with it sitting as far back as it can go. So I now need to build something simply out of necessity to fasten the circulating chamber and insert too just to finish it properly.

 

[begreen]

Google fireplace with bookcases and then look at the Images option. There are many pictures there for inspiration.

Any reason for this particular insert as opposed to another that might fit better?

 

[JayLii]

Yea it was primarily aesthetic. We wanted something pretty simple, clean and relatively modern looking.

Here is an update after work today. I'm going to put some self leveling concrete on the hearth in preparations for tiling. That is a 6"+ slab right into the crawlspace. My continued concern is around the lack of depth to fit the insert into. It requires 19.5" at the top and will be protruding out considerably. I am having a WETT inspector by tomorrow for his recommendations.

I have also picked up some furnace cement to fill the cracks and holes in the existing box.

I was pleasently surprised to see a nice mitered finished edge of red oak running perpendicular to the floor which I am going to refinish to match the rest of the floor. Going to install a marble tile that will sit flush with the floor! Not sure if I'm more excited for that or the fireplace!

Still trying to contact the shipping company for the fireplace. I've talked to them 4 times today and I can't even get an answer if it's in victoria or ontario! How hard is it to look in a warehouse for a big box??!

 

[bholler]

Yea it was primarily aesthetic. We wanted something pretty simple, clean and relatively modern looking.

Here is an update after work today. I'm going to put some self leveling concrete on the hearth in preparations for tiling. That is a 6"+ slab right into the crawlspace. My continued concern is around the lack of depth to fit the insert into. It requires 19.5" at the top and will be protruding out considerably. I am having a WETT inspector by tomorrow for his recommendations.

I have also picked up some furnace cement to fill the cracks and holes in the existing box.

I was pleasently surprised to see a nice mitered finished edge of red oak running perpendicular to the floor which I am going to refinish to match the rest of the floor. Going to install a marble tile that will sit flush with the floor! Not sure if I'm more excited for that or the fireplace!

Still trying to contact the shipping company for the fireplace. I've talked to them 4 times today and I can't even get an answer if it's in victoria or ontario! How hard is it to look in a warehouse for a big box??!

What is the current depth? It looks to me like you took the face off of the fireplace what would the depth be if you rebuilt a new masonry face? If need be add 2 courses to get the needed depth. But it will probably be difficult to hook the liner up with that much depth till you clear the lintel.

 

[JayLii]

Hey all, so I'm confused about something.

My WETT inspector told me to put roxul insulation around the liner at the top of the chimney to stop air flow and create dead air in the chimney between the liner and the clay liner.

My flex liner installation manual repeatedly says DO NOT put loose insulation between the liner and the chimney. But they do not say why... Is this simply a push for their insulated liner products??

James

 

[JayLii]

Oh and here's an update on the progress. I am finally installing the liner and the insert tomorrow after a week and half of building the built ins, painting, tile etc etc.

For those interested, I sprayed BM Advance pearl on the cabinets/bookshelves.

 

[bholler]

Hey all, so I'm confused about something.

My WETT inspector told me to put roxul insulation around the liner at the top of the chimney to stop air flow and create dead air in the chimney between the liner and the clay liner.

My flex liner installation manual repeatedly says DO NOT put loose insulation between the liner and the chimney. But they do not say why... Is this simply a push for their insulated liner products??

James

You should be using an insulated liner regardless but really you will have a top plate sealing it at the top and you should have a plate at the bottom with insulation. Stuffing some at the top wont hurt anything but it also wont do any good either

 

[blacktail]

Could it be that your manual is just warning against using regular fiberglass insulation?

 

[Kyoufu]

I was told the insulation at the top is a bad idea as it retains moisture and all the nearby contaminants and can ruin the liner prematurely. Most systems aren't fully water tight, and the brick will weep, and rain + smoke, not to mention all the stuff that has been absorbed into the brick over the years. I've never seen it myself so I can only speculate, but it seems plausible.

Interesting to see someone from my area posting here. Looks like you got it all sorted, but just for clarity any sort of framing within 6" of the sides of the fire chamber and 12" from the top is a no no regardless of combustibility. Inserts, regardless of clearances, are certified to ULC-S628 which means they can only go into a _to code_ masonry fireplace. Anything that violates the building code for masonry fireplace would put that installation outside of what it is certified for, and any WETT inspector should note that violation, and any building inspector should fail it. In Victoria and the surrounding municipalities the local authorities having jurisdiction are all quite firm on this. The only exception is a specific allowance to accommodate the liner.

Bholler: That may be how you guys install inserts, I know farther east they use blank off plates. Here I don't know a single company that does. I doubt I could buy one from a distributor or an hvac place even if i wanted to (which I don't). Most chimneys have clay liners, and we live on the west coast. Insulation wraps are only (grudgingly) used when the clay liner is compromised or missing, as the temperatures do not get much below 0. Blank off plates... well let's just say I have never seen an insert out here installed with one, and I have talked to several prominent figures who are against them.

 

[bholler]

I was told the insulation at the top is a bad idea as it retains moisture and all the nearby contaminants and can ruin the liner prematurely. Most systems aren't fully water tight, and the brick will weep, and rain + smoke, not to mention all the stuff that has been absorbed into the brick over the years. I've never seen it myself so I can only speculate, but it seems plausible.

Interesting to see someone from my area posting here. Looks like you got it all sorted, but just for clarity any sort of framing within 6" of the sides of the fire chamber and 12" from the top is a no no regardless of combustibility. Inserts, regardless of clearances, are certified to ULC-S628 which means they can only go into a _to code_ masonry fireplace. Anything that violates the building code for masonry fireplace would put that installation outside of what it is certified for, and any WETT inspector should note that violation, and any building inspector should fail it. In Victoria and the surrounding municipalities the local authorities having jurisdiction are all quite firm on this. The only exception is a specific allowance to accommodate the liner.

Bholler: That may be how you guys install inserts, I know farther east they use blank off plates. Here I don't know a single company that does. I doubt I could buy one from a distributor or an hvac place even if i wanted to (which I don't). Most chimneys have clay liners, and we live on the west coast. Insulation wraps are only (grudgingly) used when the clay liner is compromised or missing, as the temperatures do not get much below 0. Blank off plates... well let's just say I have never seen an insert out here installed with one, and I have talked to several prominent figures who are against them.

Most companies here dont do block off plates either. But they are still the best way to do it it keeps more heat in your house where you want it. And you dont buy them you make them from sheet metal.

As far as the insulation goes the existence and or condition of clay liners has absolutly no bearing on the need for insulation. It is all about clearances to combustibles listings and keeoing the temp up in the chimney. Just because everyone in your area does it one way does not mean that way is righ.

I am also curious what the reasons for being against blockoff plates is. There really is no downside.

 

[Kyoufu]

Most companies here dont do block off plates either. But they are still the best way to do it it keeps more heat in your house where you want it. And you dont buy them you make them from sheet metal.

As far as the insulation goes the existence and or condition of clay liners has absolutly no bearing on the need for insulation. It is all about clearances to combustibles listings and keeoing the temp up in the chimney. Just because everyone in your area does it one way does not mean that way is righ.

I am also curious what the reasons for being against blockoff plates is. There really is no downside.

SS liners are 1" clearance to masonry without the wrap, 0" with the wrap. So, here at least, if there is no clay liner a stainless steel liner will be failed without the insulation wrap. The other consideration is condensate which is much more of a concern in climates north and east of where I am than vancouver and victoria area of BC. It's still a better installation for sure, but most chimneys here I already have to reduce the liner size to fit it down. The reason I pointed this out though is it just so happens the original poster is from the same city as where I am located.

As for the blank off plates, it was a few years ago when last I had the conversation when the duravent guys were making their presentation, and I remember the president of WETT BC being fairly vocal about it in one of the classes I took awhile back. I know several municipalities which would fail it as the inspector needs to see the stainless liner go up.

I'm guessing the other reason is accessibility for cleaning, inspections, and for me personally the idea of having a shelf for stuff to accumulate onto above the fireplace just seems unwise (Though I realize the chimney should have been cleaned, and the smoke should be going up the SS liner, I bet stuff still accumulates). Part of it could also be blank off plates just have a bad name from the days when it was used as part of the actual venting system (with 2-3 feet of liner). I don't remember their specific reasoning though to be honest, it's been a long time since I thought about it.

 

[bholler]

SS liners are 1" clearance to masonry without the wrap, 0" with the wrap.

Well I think the numbers are slightly larger in canada but here the clearance is 1" from the outside of the masonry to any combustible material for an external chimney and 2" for an internal one. If you dont have that which very very few chimneys do you need insulation. there is no clearance required between the masonry and the liner because there would be no way to maintain that clearance. What code is it that requires insulation when there is no clay? And what is the reasoning behind it? The clay offers next to no insulation value and the flue gasses are already contained by the stainless so that clay means nothing in the equation.

The other consideration is condensate which is much more of a concern in climates north and east of where I am than vancouver and victoria area of BC.

I am not sure what condensation you are referring to. But insulation helps allot to reduce condensation of flue gasses in the liner because it helps keep internal temps up. And if you are talking about condensation outside the liner the insulation will have no effect there.

but most chimneys here I already have to reduce the liner size to fit it down.

They should not be that is a bad install then the liners should be removed to make room for a properly sized liner and if you still cant fit a properly sized liner you cant use that chimney for that appliance.

As for the blank off plates, it was a few years ago when last I had the conversation when the duravent guys were making their presentation, and I remember the president of WETT BC being fairly vocal about it in one of the classes I took awhile back.

Ok but what was his argument against them? I really see no down side at all.

I know several municipalities which would fail it as the inspector needs to see the stainless liner go up.

Yes we have a few inspectors who want to see it also and in those cases a make an inspection port in the plate.

I'm guessing the other reason is accessibility for cleaning, inspections, and for me personally the idea of having a shelf for stuff to accumulate onto above the fireplace just seems unwise (Though I realize the chimney should have been cleaned, and the smoke should be going up the SS liner, I bet stuff still accumulates)

There should never be any need to inspect or clean the area above the blockoff plate if the install was done properly. If there is stuff accumulating up there either the chimney was not cleaned properly before the install of there is a breach in the liner.

 

[Kyoufu]

Well I think the numbers are slightly larger in canada but here the clearance is 1" from the outside of the masonry to any combustible material for an external chimney and 2" for an internal one. If you dont have that which very very few chimneys do you need insulation. there is no clearance required between the masonry and the liner because there would be no way to maintain that clearance. What code is it that requires insulation when there is no clay? And what is the reasoning b ehind it? The clay offers next to no insulation value and the flue gasses are already contained by the stainless so that clay means nothing in the equation.

So this particular issue is actually kind of dumb. You are probably confused because it is confusing, and perhaps it is dealt with it better down south than how we have to deal with it up here.

I'll try to explain it, but keep in mind depending on which standard is being applied different rules have to be utilized which is part of why things get a bit convoluted. There are some definite grey areas where it ends up being "just the way it is" and, although similar, our standards are different than yours.

So ULC S640 is the CSA standard for new masonry chimneys built on site with a clay liner. There are specs a chimney must adhere to in order to be ULC S640, and likely it is similar to the rules governing masonry chimneys where you are. This is is a masonry and clay liner system, refractory cement, built on site.

The next standard is for RElining existing chimney systems. This is ULC S635 which I believe is similar to your UL1777. This link to duravent liner specs may give you some insight into the clearances, and differences between these two standards.

(broken link removed to http://duravent.com/Product.aspx?hProduct=8)

You can see the clearances listed to masonry are 1" without insulation blanket, or 0" with. What this means for us is if the chimney is deemed to be in good working condition, installed to meet ULC s640 we are allowed to install a SS liner with no insulation blanket. If there is no clay liner, the chimney is deemed obsolete, and we assume worst case and we need to install something with 0" clearance. When I first got into this I tried and tried to get a coherent explanation for this, even the head of WETTBC went on a bit of a rant about it when I asked, but basically said this is the way it is. All inspectors I have dealt with follow this.

It makes sense from the perspective that a clay liner does make a huge difference in heat transmission, as well as in resilience to damage from flue byproducts and condensate. Most chimneys without a liner are pretty seriously eroded. I prefer the duraliner insulated ridgid product over the wrap as its ULC S640, its pricey though.

I am not sure what condensation you are referring to. But insulation helps allot to reduce condensation of flue gasses in the liner because it helps keep internal temps up. And if you are talking about condensation outside the liner the insulation will have no effect there.

I was referring to condensate inside the liner due to flue gases cooling. Most areas of north america have more extreme weather than where I am, here it rarely drops more than a degree or two below freezing.[/quote]

They should not be that is a bad install then the liners should be removed to make room for a properly sized liner and if you still cant fit a properly sized liner you cant use that chimney for that appliance.

Another difference between US and Canada. Installer is permitted to reduce the liner size by up to one inch on inserts. I know that is not the case in most other areas - we have not found it to be an issue. [/quote]

Ok but what was his argument against them? I really see no down side at all.

Honestly don't remember the specifics, as I said was long ago and I have literally seen one out here ever. It was a slammer with 2 feet of liner which is a huge no no in Canada as this type of install (without a full liner) is responsible for many many chimney fires. I have seen roxul insulation used, which is allowed, but never seen a block off plate with full liner.

 

[bholler]

You can see the clearances listed to masonry are 1" without insulation blanket, or 0" with.

And how would one maintain that 1" clearance? Can you post a link to the canadian codes for me? I am interested to see them and the differences. And honestly I don't trust duravent's instructions to conform to canadian code I know there are things in them that contradict american codes which one of the reasons I will not use any of their products.

It makes sense from the perspective that a clay liner does make a huge difference in heat transmission, as well as in resilience to damage from flue byproducts and condensate. Most chimneys without a liner are pretty seriously eroded. I prefer the duraliner insulated ridgid product over the wrap as its ULC S640, its pricey though.

And how does a clay tile make a huge difference in heat transmission when it has almost no insulation value? And what possible reason would you have for needing resilience against flue gasses and condensate after a new liner is installed? That clay will no longer be in contact with them. For seriously eroded chimneys we would use a pour in insulation mix to help stabilize the chimney and for wood stoves we always use heavy flex which is as durable as rigid but much easier to install. Yes it costs more but it is the best product for the job.

I was referring to condensate inside the liner due to flue gases cooling.

Yes and that is a really good reason for insulation.

Another difference between US and Canada. Installer is permitted to reduce the liner size by up to one inch on inserts. I know that is not the case in most other areas - we have not found it to be an issue.

You are allowed to here as well as long as the manufacturer agrees it is ok. And we have seen issues on shorter chimney with stoves installed on undersized liners. Down sizing is not the best way to install.

Honestly don't remember the specifics, as I said was long ago and I have literally seen one out here ever. It was a slammer with 2 feet of liner which is a huge no no in Canada as this type of install (without a full liner) is responsible for many many chimney fires. I have seen roxul insulation used, which is allowed, but never seen a block off plate with full liner.

Well that is not a slammer that is a direct connect which for some crazy reason is still allowed by code here. I am still curious what problem you have with the function of a block off plate? Read some of the stuff posted here about the improvements in performance from people who have added them to a system. I see no reason why you would want to send extra heat up into that chimney structure other than the fact that you guys dont insulate your liners so any extra heat up there will help with your performance. But you are loosing usable heat in the house

 

[Kyoufu]

Couple things. First, any idea what the R value is on the foil wrap insulation? I doubt it actually does much to keep vapours warm, if you look at the safe'n'sound roxul the R value is pretty negligible. I looked around to verify, couldn't find a number though.

As for the R value of the clay liner, I think its more that the clay liner it is about 1" thick, so you can guarantee that 1" clearance to the masonry behind it. If it's not there, there is no way to gaurantee that clearance so you need something which is certified for 0" to masonry, which just SS liner is not, but with an insulation wrap it is.

As for the block off plate, I can't remember specifically other than what I said in earlier postings. Just general inconvenience, and considering the top is already flashed and sealed off it seems like a lot of extra work for questionable benefit. I have no experience with them though, so I really don't know what kind of difference it makes in your climate.

 

[bholler]

Couple things. First, any idea what the R value is on the foil wrap insulation? I doubt it actually does much to keep vapours warm, if you look at the safe'n'sound roxul the R value is pretty negligible. I looked around to verify, couldn't find a number though.

As for the R value of the clay liner, I think its more that the clay liner it is about 1" thick, so you can guarantee that 1" clearance to the masonry behind it. If it's not there, there is no way to gaurantee that clearance so you need something which is certified for 0" to masonry, which just SS liner is not, but with an insulation wrap it is.

As for the block off plate, I can't remember specifically other than what I said in earlier postings. Just general inconvenience, and considering the top is already flashed and sealed off it seems like a lot of extra work for questionable benefit. I have no experience with them though, so I really don't know what kind of difference it makes in your climate.

The r value is enough to reduce heat transfer to a point that it is safe to have combustibles in contact with the outside of a 4 inch masonry wall with 2100 degrees in that liner. And you are mistaken you need that 1 inch on the outside of the chimney not the inside. That and that liner which is not 1 inch anyway is part of the masonry structure and would not be counted as clearance anyway.

And yes a block off plate is an inconvenience they are a pain to install but they make a huge difference no matter what climate you are in. They keep the heat in the conditioned space of the house instead of the chimney. It is more important with an external chimney because the heat is easily lost through the masonry to outside.

There have been people here who have measured the outside temp of the chimney before and after a plate and have seen a big difference

 

[Kyoufu]

Here non combustible material does not constitute heat shielding, but it does constitute clearance. You may recall I mentioned at the start the way this issue was enforced here was fairy convoluted and confusing. I'm not saying it's right or that it makes sense , none the less that is how it is enforced in the surround 13 municipalities in my area, and as I am given to understand, the rest of BC.

Perhaps I will make a topic on the WETT site, see if anyone there has a better (semi coherent) explanation as to why it is the way it is.

 

[bholler]

Here non combustible material does not constitute heat shielding, but it does constitute clearance. You may recall I mentioned at the start the way this issue was enforced here was fairy convoluted and confusing. I'm not saying it's right or that it makes sense , none the less that is how it is enforced in the surround 13 municipalities in my area, and as I am given to understand, the rest of BC.

Perhaps I will make a topic on the WETT site, see if anyone there has a better (semi coherent) explanation as to why it is the way it is.

Just post a link to the code. Is it not the same as the national code? I found that and it is about the same as ours. And how can a non insulating non combustible material constitute clearance? Do you have different thermodynamics just in your area?

 

[Kyoufu]

Just post a link to the code. Is it not the same as the national code? I found that and it is about the same as ours. And how can a non insulating non combustible material constitute clearance? Do you have different thermodynamics just in your area?

Things seem so simple for you guys. If you want to read the code i think its about $200-$500 for each applicable standard. Applicable standards are:
ULC S 635, building code, B365, Masonry one which i don't know the name, ULC S640, ULC S628. I have some of them but not all.


This is all the information publicly available on ULC s635 which is the main one: (broken link removed)

I did however find the UL file (for duravent) and it does specify clearances to masonry, not just combustibles. The clearance to masonry is a real thing.

http://database.ul.com/cgi-bin/XYV/...n=versionless&parent_id=1073985446&sequence=1


As for our thermodynamics, I'm short a P. eng so I just apply the rules, I don't create them. In a situation where brick is directly attached to a wall with insufficient airspace, we used to measure to the surface of the brick for clearances (to the appliance). This was changed, now we measure to the combustible material behind it. Based on this mindset I was speculating something similar could be being applied to the clay liner / masonry.

 

[bholler]

I am not asking for listings i am asking for building codes. We have to pay for the listings as well but codes tell when insulation is required. And the codes are readily available.

I read allot of canadian instructions and some mention the clearance from the liner to the masonry but they all say you need the clearance from the masonry to combustibles. None say anything about clay liners or how you could possibly maintain 1 inch between the liner and the inside of the chimney the whole was

 

[Kyoufu]

I am not asking for listings i am asking for building codes. We have to pay for the listings as well but codes tell when insulation is required. And the codes are readily available.

I read allot of canadian instructions and some mention the clearance from the liner to the masonry but they all say you need the clearance from the masonry to combustibles. None say anything about clay liners or how you could possibly maintain 1 inch between the liner and the inside of the chimney the whole was

Aha, I just found one of the answers. So in Canada, the ULC S635 for relining does not provide provisions for testing for clearances to combustibles, as there are no tests on the heat transmission of the outer shell of the masonry . So essentially, ULCs635 assumes the chimney is constructed properly and up to code, and only gives clearances to that to code chimney. ULC s640 is much more thorough (and as such likely more expensive to test to).

As such, if the manufacturer only tests to ULC s635 they can only give a clearance to masonry. I did find some more thorough explanation of the standards, and an explanation o but it's not really for public consumption.

Building code is really expensive, I don't even have a copy just some relevant excerpts. You are right the clearance to combustibles for a masonry chimney is in the building code though, IIRC its 2" or 1/2" if its an outside wall. It's not relevant though, if you don't have those clearances you need a new chimney system not just a new liner.