What are these installers thinking... help with my proposed chimney...More pics..

[wi-dogfish]

I drove around this weekend a little looking at chimney idea's and styles. This house is new construction and as far as I can tell it is a wood burning chimney. This isn't the only one with the poor chimney placement. As long as showrooms can comply with the 10'-2'-3' rule do they even care what the performance of the chimney will be like? Or am I missing something here.

One of the reasons I am asking this is because I would like to put a chimney on my house with a challenging placement. If this chimney will work mine will be no problem. This is my first pic so I'll see if it works.

 

[webbie]

IN the USA, chimney are usually installed without concern as to how they will work. That one pictured probably does not even meet the code - lots of them don't. Most inspectors are not going to climb up there and check....

That chimney should extend up further - I think the building will look better also.

If you want to see some correct chimney heights, look at our gallery:
https://www.hearth.com/gallery/pics/chimney/index.html

 

[begreen]

And they tacked it on the exterior wall as an afterthought. What were they thinking indeed? :coolgrin:

 

[wi-dogfish]

Hi guys, I've been lurking here for awhile soaking up all your knowledge. Anyways I would like to put a zc fireplace on the back of my house and tear out the gas stove. What I have learned is you want to go up thru your house and keep it on the inside if possible, used insulated pac pipe and have proper clearance.

I know this is a poor pic but the only one I have small enough here to work, I will take some better pics tomorrow and post them.
Here are some dimensions to give you some rough ideas. From the ground up to the soffit is 9'. From the bottom of the soffit up to the top of the gable is about 8'. From the top of the gable up to the top of the smaller roof peak is probably another 8'. The peak of the gable(hozizontal section of roof is 10'). The plan is to go up the center of the gable, inside the house. To get my legal clearance it would be 17.5 feet of pipe. This would give me 11' of clearance two feet down from the top of the pipe. A little better than the 10' rule. I've had a few quotes to do this and no one seems concerned about chimney performance. During the winter the wind usually comes at you as your looking into the pic. This would be the NW. So the wind would be tumbling over the house at my chimney.

I've been thinking about enclosing the pipe on top of the gable at least four feet up and having 18" exposed on top of that. So that would put me 5' 6" above the gable. Then I could put another 3.5' of pipe on top of that exposed and remove this section for cleaning and that would put me about 9' of pipe on top of the gable, probably about the same height as the lower roof peaks. With some pretty good horizontal clearance. I could even take that piece of during the summer if it looks a little funny.

Should I scrape this idea and keep burning gas or do you think I could make it work without makeing the house look like some crazy woodburner lives their. I have a pellet stove in the basement and I really want a fireplace upstairs so this is not an option. The part I enclose on the top of the gable would be made with wood and siding, no brick involved.

So what do you think? Go for it or scrape the idea. All comments welcome and appreciated.

 

[begreen]

Just curious, why a ZC fireplace instead of a nice freestanding stove. Seems we are getting a lot of folks converting these units lately.

Note, all woodburners are not crazy. Only about half of us are.

 

[wi-dogfish]

I have a brick mantel in the living room already, I think we can open up the back of the house and tear out the gas stove and slide in a zc unit into the brick surround. A installer in the area has had some very good sucess doing this. My biggest concern is the chimney height. Thanks for all your timely responses, I've been kind of agonizing over this. It is kind of spendy to do this and if it doesn't work well it will be a little disappointing to say the least.

Thanks again

 

[jtp10181]

Builders do this all the time to us. The sales people tell them it is poor placement for the chimney and they just keep on doing it. The one thing we wont do though is violate the 10/2 rule. Builders have tried to tell us to "just put it in" but the installers will just put a 4ft section of metal chimney sticking out of the chase if they have to.

 

[mayhem]

Could be wrong, but I'd guess that the chimney in the first pic is for their furnace, not a stove or insert.


On your house in the second pic (nice place by the way), I'm not sure I follow your plan precisely, but basically the way I read it is you're going to wind up with a chimney sticking out of the gable end thats in the foreground of the photo and extens about 9' above that to put it just over the top of the middle peak of your roof, but still below the topmost peak...is that right? Too many roofs to keep track of here so I'm getting confused. My first thought was how hard it would be to clean it, but you've addressed that by making the topmost section removable. The only part I'm unsure of is if you need to get it above the very topmost section of roof or not...my installer told me it should extend above the very topmost section of interior airspace, regardless of the 10-2-3 rule...this is for performance and good draft.

Sounds doable...you're going to need some sort of spiderweb of bracing though to keep it up in a windstorm.

 

[wi-dogfish]

Hi guys,

This morning I took some better pics.

Mayhem, you are correct in your thinking. I need to clean the chimney somehow. The chimney will be enclosed in a chase to support it. The chase will come up at least 4' and maybe have another 5' of exposed chimney. 5' is the most the chimney can be sticking out of the chase without addition support. With 9' of total chimney. With this lenght it should clear everything except the highest peak on top of the house.

I could go higher with the chase by a foot or two but then it would start to get difficult to clean. Maybe a small step ladder with a leg on each side of the gable. Anyone have any ideas how to clean this if I go a little higher? On the backside of the chase could I put some eyebolts and then tie a small step ladder to the backside of the chase for cleaning?

Since JTP is so close to me, maybe he could come up and help me clean it.

Would I want to insulate the chase on top of the gable or is that overkill, maybe put some 1" foam on the outside of the chase before I put the siding on?

Everyone have a good day at work...

 

[TMonter]

Depending on how cold it is where you are, insulating the chase shouldn't really be necessary if you use good insulated double wall or triple wall class A chimney. Just running the chimney inside the house instead of on an outside wall makes a huge difference. (Trust me I have an outside wall chimney and it works, but it's a groan to start a draft on really cold days)

 

[TMonter]

BTW I have seen people install clips on the roof that can attach a ladder to for chimney cleaning. I think I have a picture somewhere I'll see if I can dig it up.

 

[wi-dogfish]

Now I'm thinking about building a 6' chase on top of the gable. And using some sort of permently mounted eyebolts or clips to help support a ladder for cleaning.

I think higher the better. I think it would also look better to have as much as the chimney enclosed as possible. Inside the gable portion of the roof is about 7' of attic area. Non heated. Maybe I would try to enclose the chimney in this portion and insulate it with roxul insulation. Can you just wrap this type of insulation around the insulated pipe or would I build somewhat of a frame around the pipe. Then insulate outside the frame. I know this pipe requires 2" to combustibles.

Thanks guys

 

[jtp10181]

Its not a 2" to combustibles clearance, its a 2" AIR SPACE clearance. So, no you cannot wrap insulation around it. The absolute best reccomended chase is fully insulated and sealed all the way to the top. I would have say pretty much no builders actually do this. Once it is into the attic its just plywood and framing.

 

[wi-dogfish]

So then if I wanted to I could frame around the pipe in the attic with 2x4's and plywood and leave 5" of airspace around the whole pipe just to be conservative. Then I could use sheets of foam or something on the outside of this box if I'm really wanted to seal it up?
Thanks jtp.

 

[mbcijim]

Its not a 2" to combustibles clearance, its a 2" AIR SPACE clearance. So, no you cannot wrap insulation around it. The absolute best reccomended chase is fully insulated and sealed all the way to the top. I would have say pretty much no builders actually do this. Once it is into the attic its just plywood and framing.

Ok, can you help?
I am framing my house now. Wood stove in the basement. I have a 14" x 14" chase and a 6" (8"?) double wall class A chimney.
Can you give me construction details? Do I insulate the chimney or the chase? What do you mean by sealed?

 

[jtp10181]

wi-dogfish, yeah you could use foam on the outside or on the inside, just so the pipe keeps its 2". Even the foam will help to retain some heat in the chase and keep the pipe warmer once it gets going.

mbcijim, what do you mean by construction details? At minimum you want to insulate and drywall the chase area while it is below the attic level. Above the attic you can also insulate and drywall (or seal it in some other way) the chase for extra warmth retention in the chase. I say to seal the insulation because fiberglass insulation only works if it has an air barrier on all 6 sides. The fiberglass itself only prevents thermal transfer, not air movement. The other option would be to use foam board.

 

[wi-dogfish]

Thanks everyone,

I will take all of this into consideration.

 

[mbcijim]

mbcijim, what do you mean by construction details? At minimum you want to insulate and drywall the chase area while it is below the attic level. Above the attic you can also insulate and drywall (or seal it in some other way) the chase for extra warmth retention in the chase. I say to seal the insulation because fiberglass insulation only works if it has an air barrier on all 6 sides. The fiberglass itself only prevents thermal transfer, not air movement. The other option would be to use foam board.

I have bare studs (inside dimensions 14" x 14").

Should I wrap the chimney itself in fiberglass insulation, or do I just insulate the studs/chase? The foam board I assume would go between the studs if I went that route? And by drywalling the chase, I assume you mean the outside of the chase? I have a dead space (inaccesible) between the ceiling of the first floor and the roof. It's a good 10'+ I have a 12/12 pitch roof.

I think I am reading that you recommend insulating & drywall the chase. The chimney is on an interior wall. It is about 10' from an exterior wall.

Thanks for your help.

 

[jtp10181]

You must not have read the other posts. "Its not a 2” to combustibles clearance, its a 2” AIR SPACE clearance." So NO you CAN NOT wrap the pipe in fiberglass!

You can do whatever you want as long as you don't violate the 2" clearances. The chase area that is below the attic should be included inside of the envelope of the house and insulated / sealed in the same manor. If it is an inside wall/chase then it is already inside the envelope so you don't have to do anything except have a draft stop at the ceiling level. If any of this is not done that will be a weak spot in the home and let cold air in. Once into the attic area the chase can be left to breathe with the attic or it could be sealed up and insulated as well. As I said, no one around here does that and we don't have problems. It gets pretty cold here sometimes.