Attaching Insulation to Stove Surround

[sr73087]

So I am repainting the whole stove and surround. There is some old grimmy/sooty insulation on the surround. I figured I would scrap that off before I repaint. I have 2 questions:

- Is this the correct Roxul insulation for behind the surround?
https://www.lowes.com/pd/ROCKWOOL-W...-with-Sound-Barrier-23-in-W-x-47-in-L/3693532

-What can be used to attach the insulation to the surround? Will a medium tack glue hold up or is there something special?

 

[webby3650]

You can use 3M spray adhesive and fiberglass for this. Does the insert have a liner attached to it?

 

[sr73087]

Not currently just the 6" outlet. Debating if I am going to install a full liner or run a short 4 ft liner to the terracotta liner, seems like people are on both sides of that issue. The problem for me is dumping a bunch of money into a liner and we may move in the spring.

Likely doing a block off plate as well, can the rockwool work above that and around the liner if I run it full length?

Ok I see Rutland makes some insulation that will work to on the surround.

 

[webby3650]

No one is really on the fence about the full liner, it’s the only way to go. If you do a liner and block off plate then there’s no need for insulation behind the panel. Liner manufacturers make insulation kits specifically for liners. It’s ceramic wool with an aluminum backing attached to it.

 

[sr73087]

I know it would be better if I lined it, but the idea behind the setup was to try and save some $$ on the gas bill. I have free wood and want to take advantage of it. So I want to do it smart, not cut corners, but not spend if its not necessary. I also may be leaving this area before the 2019/2020 burning season, so that cuts into my decision too.

I just cleaned the chimney and there wasn't a whole lot in there, but with my proposed setup, it would accessible and easily be cleaned each year. So I am not super worried about build up, unless the buildup would be excessive to the point where a fire could happen in 1 burning season without the liner. Keep in mind I would be venting it to the terracotta liner, not just dumping it into the firebox.There are a few people in the area I know that ran their stoves without a liner and never had an issue. With that being said, if I can pull the liner out, maybe I just do it for max efficiency and bring it with me if I move. Not sure how easy they come out. Below are a few links I found with some dialog back and forth.

My fireplace is roughly 20 feet tall, it ends about 2 ft above the roof line. The liner is a square, roughly 10.5x10.5 ID. Currently running a chimney cap. The top maybe 15 feet is exposed to the outside, the bottom 5 feet above the fireplace backs to the garage, which does get cold, but warmer than outside and sheltered from wind and moisture. Currently with the standard wood burning fireplace setup I always get a really good draft and never an issue with smoke.

Just trying to do my homework and make the best decision. I really appreciate your help.

I understand this is not the best resource but its something.
https://www.homesteadingtoday.com/threads/does-my-new-woodstove-have-to-have-a-liner.420607/

https://www.hearth.com/talk/threads/does-an-insert-need-a-flue-liner.125855/

This article does not say you necessary NEED one.
https://www.hearth.com/talk/wiki/do-you-need-a-chimney-liner/

My setup would be similar to Figure 2, with the back few inches of the stove behind the surround.
(broken link removed to https://www.uidaho.edu/-/media/UIdaho-Responsive/Files/Extension/forestry/WFS15-Installation-of-Wood-Stoves-in-Fireplaces.pdf?la=en&hash=BB52C1EFC2A42E61A75CF6FE9F679CE528B74FD9)

 

[sr73087]

No one is really on the fence about the full liner, it’s the only way to go. If you do a liner and block off plate then there’s no need for insulation behind the panel. Liner manufacturers make insulation kits specifically for liners. It’s ceramic wool with an aluminum backing attached to it.

I read one block off plate tutorial where they used rock board but said an alternative above the sheetmetal plate was ceramic wool. I guess with the liner and it sealed at the top already, it would be overkill?

 

[webby3650]

I think we may be talking about 2 different things here. The block off plate that’s mounted above the insert should have insulation on top of it. With the block off plate and a full liner, there’s no need to insulate the surround panels.

 

[bholler]

Not currently just the 6" outlet. Debating if I am going to install a full liner or run a short 4 ft liner to the terracotta liner, seems like people are on both sides of that issue. The problem for me is dumping a bunch of money into a liner and we may move in the spring.

Likely doing a block off plate as well, can the rockwool work above that and around the liner if I run it full length?

Ok I see Rutland makes some insulation that will work to on the surround.

Yeah no one is on the fence. It is to code to do a direct connect install if you meet sime criteria.

1. The chimney needs to be to code. Meaning clay liners can have no cracks and the joints between them need to be mortared properly with no gaps. You also need to have proper clearances from the outside of the chimney structure to any combustibles. There are many other things but those are the most common problems that are not met.

2. If you get past number 1 then the clay liner can be no more than 3 times the volume of the stove outlet.

3. You then need to figure out how to make a positive connection to the clay liner with your stainless pipe.

Even after all that your performance will suffer greatly with a direct connect and maintenance will be a pain.

 

[sr73087]

Would it ever make sense to run a slightly larger liner to keep your options open for a bigger stove in the future? Or will this greatly affect the draft? So instead of a 6" go with an 8"?

 

[bholler]

Would it ever make sense to run a slightly larger liner to keep your options open for a bigger stove in the future? Or will this greatly affect the draft? So instead of a 6" go with an 8"?

No it will seriously effect performance. It is about a 78% increase in volume. Not exactly what i would call a slight increase

 

[kennyp2339]

I'd do a full cleaning of the chimney and existing upper chamber / smoke shelf, install a full liner and do a block off plate, this is insurance that you wont develop any smells or anything, you don't want potential buyers referring to your house as the stinky fireplace house when looking at potential properties.

 

[sr73087]

Isn't this product for running without a liner?
(broken link removed to https://www.northlineexpress.com/connector-sealing-kit-18964.html)

Either way, I am going to run a liner based on everything you mentioned. I am also hearing that nationally code says we need to insulate the liner? Is this true? It doesn't sound like everyone does this but most of the members on here would know better.

 

[yooper08]

Nationally, code says you must insulate the liner if your chimney doesn't meet code. Very few chimneys meet code requirements for clearances to combustibles (per resident experts). So by proxy, nationally, most people need to insulate their liner. Everyone doesn't do it, whether by conscious choice or unaware of the requirement, but the safety value it provides (after all, we are talking about our homes) and the performance of insulating are worth it.

 

[sr73087]

Will it normally make much of a difference in performance with a 20-25' chimney that is partially sheltered?

 

[bholler]

Isn't this product for running without a liner?
(broken link removed to https://www.northlineexpress.com/connector-sealing-kit-18964.html)

Either way, I am going to run a liner based on everything you mentioned. I am also hearing that nationally code says we need to insulate the liner? Is this true? It doesn't sound like everyone does this but most of the members on here would know better.

Yes that is what that is for. But it doesnt change the criteria i listed above that must be met to install itvin that way.

 

[yooper08]

I'll let webby and bholler chime in on that one but here's my take.

The further the run, the more the flue gas will cool before it exits. That said, where you'll see performance and safety improvement is less cooling of flue gasses near the top as the insulation keeps it warmer. This translates into less creosote buildup and less problems down the road, such as plugged flue and/or cap. It also translates into more consistent draft as well as quicker establishment of draft on cold starts due to a faster warm up time.

My own setup is about 27 feet in an exterior chimney, insulated. I've never had creosote form on my cap and minimal buildup inside the flue.

 

[yooper08]

Keep in mind, the only reason for the insulation requirement is to prevent your house from burning down. Everything else you get from it is sprinkles on top, maybe a cherry, too.

 

[bholler]

Keep in mind, the only reason for the insulation requirement is to prevent your house from burning down. Everything else you get from it is sprinkles on top, maybe a cherry, too.

Well said.

 

[peakbagger]

Please whatever you do make sure the insulation you scrape off isnt asbestos. It was used on heat shields for years.

 

[sr73087]

Good call. Is there an easy way to know? I know they have those kits for lead paint, not sure for asbestos.

 

[peakbagger]

I think there are kits where you take a sample an send it to pro to take a look at it under a Polarized Ligh Microscope (PLM).

 

[sr73087]

If I take a picture would that help anyone determine? It looks more like fiberglass than the asbestos photos I have seen, since it is more stranded that the asbestos looks. But I do really want to know for sure.

Does anyone know when it was mandated that they stop using asbestos insulation for stoves? If that date is well before the stove manufacture date it should help rule it out.

 

[peakbagger]

http://www.ehso.com/cssasbestos/asbestosban.htm