What are your opinions about a chimney near roof's ridgeline

4" seems too tight to install - would think the ridge line joist would be too close. Class A chimney needs 2" air clearance - so, a 6" ID is 8" + 2" +2" = 12" minimum hole in roof deck with pipe centered. I'd move down from the ridge by 2ft or so. 2 x 15* elbows in black stove pipe should do it. . Here is one of mine:

Assume you're talking metal, and not masonry, here?

dougand3 said:

4" seems too tight to install - would think the ridge line joist would be too close. Class A chimney needs 2" air clearance - so, a 6" ID is 8" + 2" +2" = 12" minimum hole in roof deck with pipe centered. I'd move down from the ridge by 2ft or so. 2 x 15* elbows in black stove pipe should do it. . Here is one of mine:

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+1

Clearances would be the only issue I can think of.

You need to be further down hill from the ridge. If you are in the 6 pitch range, you need about 13" from the ridge to the center of the pipe. (If I remember right). Just to fit it in, further if you don't want to mess with the ridge cap shingles.
If your chimney is tall, like 18' or more, then just use a set of 30 degree elbows in the attic. It will draw fine, it will only make a noticeable difference if you are near the minimum height with the flue. 30 degree elbows will perform better than 45's in the room, and it looks way better.

Ideally you want the chimney to exit the roof at the highest point of the roof while maintaining clearances. Even with insulated pipe, its still a heck of lot better to have the maximum length of the chimney inside the building instead of outside.

That's about the best arrangement. No outside chimney support, easy to top down clean, If you can get up there. Straight inside chimneys, draft better.

7acres said:

I am locating my new wood stove in a very central location of the house. Almost dead center side to side and front to back. Where it is located the chimney, if it had no offset, would exit the roof about 4' away from the roof's ridgeline (on the backside of the house). I've learned on this forum that a straight shot with no Ts or offsets is ideal if you have that option.

But it seems to me like most people don't have their chimney that close to the ridgeline. That may just be coincidence as most people have their wood stove/fireplace near an outside wall. Is there any reason I should shy away from a straight shot and use an offset to have the chimney exit more toward the back of the house rather than right near the ridgeline?

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I think you'll find that a lot of the older homes did in fact have a chimney at the center of the home . . . there may also have been a chimney or two at the home's ends depending on the size of the home and location of the chimney. Keeping the stove and heat at the home's center was -- and to a degree -- even today -- is desirable. In the older homes having a stove or fireplace at the home's ends as well may have been done due to the size of the home and need for more heat or because the kitchen was kept a bit further away from the home as it can get pretty darned warm while baking in July and August.

As for modern homes . . . chimneys are often found on the ends as folks who may or may not be looking for optimal heating don't want to give up floor space to a heating appliance (or in many cases these are simply fireplaces which will receive only occasional use). In other cases it may be that the home's layout is not conducive to centering the stove. In my case, centering the stove would have placed it in my hallway . . . a bit inconvenient, not to mention that to me one of the more important factors in placing the stove is to put it where you will generally spend the most waking hours in the home . . . then you get the most benefit from any radiated heat, the view, the ability to easily monitor the fire, etc.

Good post, Jake. Also, culture / heritage played heavily into this, just as all construction trades in colonial times. The Germans and Scandinavians built log homes, while this was completely foreign to early English settlers, who built framed or stone homes. Likewise, the Quakers in Philadelphia (from middle England) were building end chimney homes, while the Puritans in Boston (from northern England) were building center chimney homes. Whether this tradition was driven by local weather, the size of the homes (most of these dual end-chimney Philadelphia homes were much bigger than you'd find in New England), or simply tradition is a matter of debate.

7acres said:

But it seems to me like most people don't have their chimney that close to the ridgeline.

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My house was built in the 60's and the roof ridgeline goes around the chimney. It is literally through the ridgeline of the house.

I like it for 2 reasons:
- Cleaning it is easy because I have really good footing standing at the ridge
- I almost don't need flashing around it and will probably never have a roof leak because of it

Now that said, I ran a liner through this existing chimney, so I didn't have a choice. I would not run a new chimney through the ridgeline of my home, because that would mean cutting the ridgeline and weakening my roof.

I do think you have a nearly ideal situation (as long as you are able to clean it). 4 feet from the ridge is plenty.

smokedragon said:

I would not run a new chimney through the ridgeline of my home, because that would mean cutting the ridgeline and weakening my roof.

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Not an issue, if you support the ridge on either side of the cut, but consultation with a structural engineer is a must. He will tell you to either use collar ties (at least 1/3 way down the rafter span) on either side of the cut, or beef up the corresponding joists and install a post under the ridge on either side of the cut. Neither fix is trivial, but both very do-able as retrofit work.

Joful said:

Neither fix is trivial

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Which is exactly why I would never go through my ridge

smokedragon said:

Which is exactly why I would never go through my ridge

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I understand your sentiment, but do keep in mind I have owned a very long list of houses and other buildings that are all over 200 years old. Very few of them have had ridge joists or ridge beams, but they're still standing square. I wonder how many of today's houses, built to modern code, will hold up so well?

The original poster is in the SouthEast, but I would think the higher the chimney is on the roof, the less chance of snow and ice taking it out.

Joful said:

I understand your sentiment, but do keep in mind I have owned a very long list of houses and other buildings that are all over 200 years old. Very few of them have had ridge joists or ridge beams, but they're still standing square. I wonder how many of today's houses, built to modern code, will hold up so well?

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I don't disagree with you, but they were built out of much heavier lumber and were designed very differently. 200+ year old homes that are in good repair are amazing. They will never be built like that again, which is sad.

However, I am a big fan of not cutting out and then trying to repair/redo main structural members, especially if a few 30's will let me avoid it.

My chimney is about 2' from the ridge, very easy to clean. Works for me.

WES999 said:

My chimney is about 2' from the ridge, very easy to clean. Works for me.
View attachment 135540

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Mine's right thru the ridge, and anything but easy to clean.



Even my chimney sweep admits to being nervous going up on this one. Nice slippy metal roof, equipped with meat... err, "ice" hooks, too.