Class A Chimny Question

[MaintenanceMan]

Hi, this is my first post here. I've been lurking and living vicariously through this forum for a while. I don't currently burn wood, but have been attracted to it since my childhood. My wife and I are tossing around the idea of putting in a stove in the living area of our small home mainly for supplemental and emergency heat. Our planned location for the stove would prevent putting a class-A chimney straight through the roof. My question would be is it just a bad idea all together to put in a chimney with two 30degree elbows in the attic? I'm pretty leery of this rout mainly because I've never seen a chimney installed like this although I have seen it laid out in such a manner in other places/diagrams etc. I've installed my fair share of b-vent and various other appliance vent pipe in the past as a HVAC contractor, but hardly any Class-A.

This would be pretty much what I would have to do.

Thanks in advance for any insight.

 

[dougand3]

Welcome, MaintenanceMan. Straight up is preferable. Draft should be better and easier to clean. Class A chimney is heavy - it's supported much better on the ceiling support box when going vertical. Go to Lowes, HD or stove shop and heft a 3 ft section. Looking at your drawing - I don't know if they make class A 30 deg elbows. If they do - sounds EXPENSIVE. And the class A at 30 deg angle - supported only by locking bands? - scary (Dunno if this would even be in code). Google Selkirk and check the install manual. I know I'd rather have the class A weight resting on the CSB - as chimney exits roof decking, the support is hi temp silicone under the storm collar - not much.

 

[Backwoods Savage]

Welcome to the forum MaintenanceMan.

When installing a new chimney, first consider how you will clean that chimney, which all wood burning stoves will require. It looks to me like that would be a problem cleaning that. Perhaps you can move the stove so as to be able to go straight up. Or you might consider going through the wall and then up the side of the house. We have that and have no problems with it and it is simple and easy to clean. If you do go horizontal, it requires a minimum of 1/4" rise per foot of horizontal pipe.

Good luck.

 

[webby3650]

I clean lots of class A with 30° offsets, never have a problem getting a ploy brush down.

 

[daryl]

30 degree elbows do not hurt a thing. A chimney brush goes right on down. Just make sure to support it well with proper offset supports,banded or screwed joints. One thing to consider is for every foot you move over you need 2' and a couple of inchs of headroom. Sometimes it is just easier to build a chase on the roof and have a little more chimney coming out the roof.

 

[MaintenanceMan]

Thanks for the replies! The draft and cleaning the chimney were my main concerns. Adequate support won't be a problem.

One thing to consider is for every foot you move over you need 2' and a couple of inchs of headroom. Sometimes it is just easier to build a chase on the roof and have a little more chimney coming out the roof.

Are you saying that for every horizontal foot I need two additional feet of rise? Thanks.

 

[begreen]

The rise in the class A run will be determined by the slope created by the 30° elbow. Elbows can not be combined to create a greater angle. Simpson strongly recommends no greater than a 72" run between the lower and upper elbows. On the connector side, (not the HT classA pipe side), if there is a horiz. run, it should be short and pitched upward a minimum of 1/4" per ft.

 

[MaintenanceMan]

Well, so far it sounds like my plans might work out. The stove pipe would vent off the top of the stove, straight to the ceiling. The class-A would have about a three or four foot diagonal run between elbows. Everything else would be completely vertical.

 

[daryl]

Thanks for the replies! The draft and cleaning the chimney were my main concerns. Adequate support won't be a problem.

One thing to consider is for every foot you move over you need 2' and a couple of inchs of headroom. Sometimes it is just easier to build a chase on the roof and have a little more chimney coming out the roof.

Are you saying that for every horizontal foot I need two additional feet of rise? Thanks.

Yep,