Question from a very green newbie

[fossil]

The length (height) of chimney required in any application is typically determined by application of the "3-2-10 rule". In no case may a chimney extend fewer than 3 feet above the point at which it penetrates the roof. It must then extend further, if necessary, to a point no fewer than 2 feet above any part of the structure within 10 feet horizontally from the chimney. So, it depends on your roof pitch and on the point at which your chimney exits the roof. Rick

EDIT: Your existing chimney appears to me, from the pics provided, as though it might actually be taller than it needs to be. But, it's hard to tell from the ground-view angle of the pics.

 

[begreen]

I'm also suspecting that the current flue is many feet taller than it need be. Go up on the roof with a 12 ft tape measure and a marker. Measure ten feet horizontally from the roof to the chimney and mark that point. Then measure from the base of the flue to that mark. Add 24" to that measurement. That will be the height of the new flue pipe.

Class A pipe is insulated, so it's going to stay much hotter on its interior then the single-wall pipe that is currently in use. That should dramatically reduce creosote condensation. However, if your mom is burning unseasoned wood that is not fully dried, there will still be some creosote produced, especially if she is unable to keep a hot enough fire going due to damp wood. By far the majority of creosote issues we see here are due to burning too cool, caused by too damp wood.

I thought about your mom most of last night. Wish I lived close by, I'd be there to help you out. There is a risk of the current pipe blowing down or bending over in a good windstorm. If that occurred while a fire was going it could be serious. Please consider this.

Were you able to find any labeling on the pipe in the attic? Maybe take the camera up there and take a shot of that too on the outside chance that someone here will be able to ID it.